diff --git a/pylib/.isort.cfg b/pylib/.isort.cfg
index e3baa20af..2c1fbb53b 100644
--- a/pylib/.isort.cfg
+++ b/pylib/.isort.cfg
@@ -1,5 +1,5 @@
 [settings]
-skip=aqt/forms,backend_pb2.py,backend_pb2.pyi,fluent_pb2.py,fluent_pb2.pyi,rsbackend_gen.py,hooks_gen.py,genbackend.py
+skip=aqt/forms,backend_pb2.py,backend_pb2.pyi,fluent_pb2.py,fluent_pb2.pyi,rsbackend_gen.py,generated.py,hooks_gen.py,genbackend.py
 profile=black
 multi_line_output=3
 include_trailing_comma=True
diff --git a/pylib/anki/BUILD.bazel b/pylib/anki/BUILD.bazel
index 58df9805a..cb9304ea4 100644
--- a/pylib/anki/BUILD.bazel
+++ b/pylib/anki/BUILD.bazel
@@ -1,7 +1,6 @@
 load("@bazel_skylib//rules:copy_file.bzl", "copy_file")
 load("@rules_python//python:defs.bzl", "py_library")
 load("@py_deps//:requirements.bzl", "requirement")
-load("//pylib:protobuf.bzl", "py_proto_library_typed")
 load("@rules_python//experimental/python:wheel.bzl", "py_package", "py_wheel")
 load("@bazel_skylib//lib:selects.bzl", "selects")
 load("//:defs.bzl", "anki_version")
@@ -13,13 +12,6 @@ copy_file(
     out = "buildinfo.txt",
 )
 
-genrule(
-    name = "rsbackend_gen",
-    outs = ["rsbackend_gen.py"],
-    cmd = "$(location //pylib/tools:genbackend) > $@",
-    tools = ["//pylib/tools:genbackend"],
-)
-
 genrule(
     name = "hooks_gen",
     outs = ["hooks_gen.py"],
@@ -27,22 +19,6 @@ genrule(
     tools = ["//pylib/tools:genhooks"],
 )
 
-py_proto_library_typed(
-    name = "backend_pb2",
-    src = "//rslib:backend.proto",
-    visibility = [
-        "//visibility:public",
-    ],
-)
-
-py_proto_library_typed(
-    name = "fluent_pb2",
-    src = "//rslib:fluent.proto",
-    visibility = [
-        "//visibility:public",
-    ],
-)
-
 copy_file(
     name = "rsbridge_unix",
     src = "//pylib/rsbridge",
@@ -69,7 +45,6 @@ alias(
 _py_srcs = glob(
     ["**/*.py"],
     exclude = [
-        "rsbackend_gen.py",
         "hooks_gen.py",
     ],
 )
@@ -79,12 +54,10 @@ py_library(
     srcs = _py_srcs,
     data = [
         "py.typed",
-        ":backend_pb2",
         ":buildinfo",
-        ":fluent_pb2",
         ":hooks_gen",
-        ":rsbackend_gen",
         ":rsbridge",
+        "//pylib/anki/_backend",
     ],
     imports = [
         "..",
diff --git a/pylib/anki/_backend/BUILD.bazel b/pylib/anki/_backend/BUILD.bazel
new file mode 100644
index 000000000..02391c8e7
--- /dev/null
+++ b/pylib/anki/_backend/BUILD.bazel
@@ -0,0 +1,50 @@
+load("@rules_python//python:defs.bzl", "py_binary")
+load("@py_deps//:requirements.bzl", "requirement")
+load("//pylib:protobuf.bzl", "py_proto_library_typed")
+
+py_proto_library_typed(
+    name = "backend_pb2",
+    src = "//rslib:backend.proto",
+    visibility = [
+        "//visibility:public",
+    ],
+)
+
+py_proto_library_typed(
+    name = "fluent_pb2",
+    src = "//rslib:fluent.proto",
+    visibility = [
+        "//visibility:public",
+    ],
+)
+
+py_binary(
+    name = "genbackend",
+    srcs = [
+        "backend_pb2",
+        "genbackend.py",
+    ],
+    deps = [
+        requirement("black"),
+        requirement("stringcase"),
+        requirement("protobuf"),
+    ],
+)
+
+genrule(
+    name = "rsbackend_gen",
+    outs = ["generated.py"],
+    cmd = "$(location genbackend) > $@",
+    tools = ["genbackend"],
+)
+
+filegroup(
+    name = "_backend",
+    srcs = [
+        "__init__.py",
+        ":backend_pb2",
+        ":fluent_pb2",
+        ":rsbackend_gen",
+    ],
+    visibility = ["//pylib:__subpackages__"],
+)
diff --git a/pylib/anki/rsbackend.py b/pylib/anki/_backend/__init__.py
similarity index 52%
rename from pylib/anki/rsbackend.py
rename to pylib/anki/_backend/__init__.py
index aa1a886cd..9ed58cece 100644
--- a/pylib/anki/rsbackend.py
+++ b/pylib/anki/_backend/__init__.py
@@ -22,19 +22,19 @@ import os
 from dataclasses import dataclass
 from typing import TYPE_CHECKING, Any, Dict, List, Optional, Sequence, Union
 
+import anki._backend.backend_pb2 as pb
 import anki._rsbridge
-import anki.backend_pb2 as pb
 import anki.buildinfo
 from anki import hooks
+from anki._backend.generated import RustBackendGenerated
 from anki.dbproxy import Row as DBRow
 from anki.dbproxy import ValueForDB
-from anki.fluent_pb2 import FluentString as TR
-from anki.rsbackend_gen import RustBackendGenerated
+from anki.errors import backend_exception_to_pylib
+from anki.lang import FormatTimeSpanContext
+from anki.utils import from_json_bytes, to_json_bytes
 
 if TYPE_CHECKING:
-    from anki.fluent_pb2 import FluentStringValue as TRValue
-
-    FormatTimeSpanContextValue = pb.FormatTimespanIn.ContextValue
+    from anki.lang import FormatTimeSpanContextValue, TRValue
 
 assert anki._rsbridge.buildhash() == anki.buildinfo.buildhash
 
@@ -48,151 +48,10 @@ BackendNote = pb.Note
 Tag = pb.Tag
 TagTreeNode = pb.TagTreeNode
 NoteType = pb.NoteType
-DeckTreeNode = pb.DeckTreeNode
 StockNoteType = pb.StockNoteType
 ConcatSeparator = pb.ConcatenateSearchesIn.Separator
-SyncAuth = pb.SyncAuth
-SyncOutput = pb.SyncCollectionOut
-SyncStatus = pb.SyncStatusOut
 CountsForDeckToday = pb.CountsForDeckTodayOut
 
-try:
-    import orjson
-
-    to_json_bytes = orjson.dumps
-    from_json_bytes = orjson.loads
-except:
-    print("orjson is missing; DB operations will be slower")
-    to_json_bytes = lambda obj: json.dumps(obj).encode("utf8")  # type: ignore
-    from_json_bytes = json.loads
-
-
-class Interrupted(Exception):
-    pass
-
-
-class StringError(Exception):
-    def __str__(self) -> str:
-        return self.args[0]  # pylint: disable=unsubscriptable-object
-
-
-NetworkErrorKind = pb.NetworkError.NetworkErrorKind
-SyncErrorKind = pb.SyncError.SyncErrorKind
-
-
-class NetworkError(StringError):
-    def kind(self) -> pb.NetworkError.NetworkErrorKindValue:
-        return self.args[1]
-
-
-class SyncError(StringError):
-    def kind(self) -> pb.SyncError.SyncErrorKindValue:
-        return self.args[1]
-
-
-class IOError(StringError):
-    pass
-
-
-class DBError(StringError):
-    pass
-
-
-class TemplateError(StringError):
-    pass
-
-
-class NotFoundError(Exception):
-    pass
-
-
-class ExistsError(Exception):
-    pass
-
-
-class DeckIsFilteredError(Exception):
-    pass
-
-
-class InvalidInput(StringError):
-    pass
-
-
-def proto_exception_to_native(err: pb.BackendError) -> Exception:
-    val = err.WhichOneof("value")
-    if val == "interrupted":
-        return Interrupted()
-    elif val == "network_error":
-        return NetworkError(err.localized, err.network_error.kind)
-    elif val == "sync_error":
-        return SyncError(err.localized, err.sync_error.kind)
-    elif val == "io_error":
-        return IOError(err.localized)
-    elif val == "db_error":
-        return DBError(err.localized)
-    elif val == "template_parse":
-        return TemplateError(err.localized)
-    elif val == "invalid_input":
-        return InvalidInput(err.localized)
-    elif val == "json_error":
-        return StringError(err.localized)
-    elif val == "not_found_error":
-        return NotFoundError()
-    elif val == "exists":
-        return ExistsError()
-    elif val == "deck_is_filtered":
-        return DeckIsFilteredError()
-    elif val == "proto_error":
-        return StringError(err.localized)
-    else:
-        print("unhandled error type:", val)
-        return StringError(err.localized)
-
-
-MediaSyncProgress = pb.MediaSyncProgress
-FullSyncProgress = pb.FullSyncProgress
-NormalSyncProgress = pb.NormalSyncProgress
-DatabaseCheckProgress = pb.DatabaseCheckProgress
-
-FormatTimeSpanContext = pb.FormatTimespanIn.Context
-
-
-class ProgressKind(enum.Enum):
-    NoProgress = 0
-    MediaSync = 1
-    MediaCheck = 2
-    FullSync = 3
-    NormalSync = 4
-    DatabaseCheck = 5
-
-
-@dataclass
-class Progress:
-    kind: ProgressKind
-    val: Union[
-        MediaSyncProgress,
-        pb.FullSyncProgress,
-        NormalSyncProgress,
-        DatabaseCheckProgress,
-        str,
-    ]
-
-    @staticmethod
-    def from_proto(proto: pb.Progress) -> Progress:
-        kind = proto.WhichOneof("value")
-        if kind == "media_sync":
-            return Progress(kind=ProgressKind.MediaSync, val=proto.media_sync)
-        elif kind == "media_check":
-            return Progress(kind=ProgressKind.MediaCheck, val=proto.media_check)
-        elif kind == "full_sync":
-            return Progress(kind=ProgressKind.FullSync, val=proto.full_sync)
-        elif kind == "normal_sync":
-            return Progress(kind=ProgressKind.NormalSync, val=proto.normal_sync)
-        elif kind == "database_check":
-            return Progress(kind=ProgressKind.DatabaseCheck, val=proto.database_check)
-        else:
-            return Progress(kind=ProgressKind.NoProgress, val="")
-
 
 class RustBackend(RustBackendGenerated):
     def __init__(
@@ -240,7 +99,7 @@ class RustBackend(RustBackendGenerated):
             err_bytes = bytes(e.args[0])
         err = pb.BackendError()
         err.ParseFromString(err_bytes)
-        raise proto_exception_to_native(err)
+        raise backend_exception_to_pylib(err)
 
     def translate(self, key: TRValue, **kwargs: Union[str, int, float]) -> str:
         return self.translate_string(translate_string_in(key, **kwargs))
@@ -263,7 +122,7 @@ class RustBackend(RustBackendGenerated):
             err_bytes = bytes(e.args[0])
         err = pb.BackendError()
         err.ParseFromString(err_bytes)
-        raise proto_exception_to_native(err)
+        raise backend_exception_to_pylib(err)
 
 
 def translate_string_in(
diff --git a/pylib/anki/_backend/backend_pb2.pyi b/pylib/anki/_backend/backend_pb2.pyi
new file mode 120000
index 000000000..fb507905b
--- /dev/null
+++ b/pylib/anki/_backend/backend_pb2.pyi
@@ -0,0 +1 @@
+../../../bazel-bin/pylib/anki/_backend/backend_pb2.pyi
\ No newline at end of file
diff --git a/pylib/anki/_backend/fluent_pb2.pyi b/pylib/anki/_backend/fluent_pb2.pyi
new file mode 120000
index 000000000..a2c47c62e
--- /dev/null
+++ b/pylib/anki/_backend/fluent_pb2.pyi
@@ -0,0 +1 @@
+../../../bazel-bin/pylib/anki/_backend/fluent_pb2.pyi
\ No newline at end of file
diff --git a/pylib/tools/genbackend.py b/pylib/anki/_backend/genbackend.py
similarity index 98%
rename from pylib/tools/genbackend.py
rename to pylib/anki/_backend/genbackend.py
index 3074bde63..75d566d45 100755
--- a/pylib/tools/genbackend.py
+++ b/pylib/anki/_backend/genbackend.py
@@ -5,7 +5,7 @@ import os
 import re
 import sys
 
-import pylib.anki.backend_pb2 as pb
+import pylib.anki._backend.backend_pb2 as pb
 
 import stringcase
 
@@ -168,7 +168,7 @@ col.decks.all_config()
     
 from typing import *
 
-import anki.backend_pb2 as pb
+import anki._backend.backend_pb2 as pb
 
 class RustBackendGenerated:
     def _run_command(self, method: int, input: Any) -> bytes:
diff --git a/pylib/anki/_backend/generated.py b/pylib/anki/_backend/generated.py
new file mode 120000
index 000000000..922921371
--- /dev/null
+++ b/pylib/anki/_backend/generated.py
@@ -0,0 +1 @@
+../../../bazel-bin/pylib/anki/_backend/generated.py
\ No newline at end of file
diff --git a/pylib/anki/backend_pb2.pyi b/pylib/anki/backend_pb2.pyi
deleted file mode 120000
index d3937d76d..000000000
--- a/pylib/anki/backend_pb2.pyi
+++ /dev/null
@@ -1 +0,0 @@
-../../bazel-bin/pylib/anki/backend_pb2.pyi
\ No newline at end of file
diff --git a/pylib/anki/cards.py b/pylib/anki/cards.py
index 324b0bd3e..9feb923ea 100644
--- a/pylib/anki/cards.py
+++ b/pylib/anki/cards.py
@@ -8,11 +8,11 @@ import time
 from typing import List, Optional
 
 import anki  # pylint: disable=unused-import
+import anki._backend.backend_pb2 as _pb
 from anki import hooks
 from anki.consts import *
 from anki.models import NoteType, Template
 from anki.notes import Note
-from anki.rsbackend import BackendCard
 from anki.sound import AVTag
 
 # Cards
@@ -45,14 +45,14 @@ class Card:
             self.load()
         else:
             # new card with defaults
-            self._load_from_backend_card(BackendCard())
+            self._load_from_backend_card(_pb.Card())
 
     def load(self) -> None:
         c = self.col.backend.get_card(self.id)
         assert c
         self._load_from_backend_card(c)
 
-    def _load_from_backend_card(self, c: BackendCard) -> None:
+    def _load_from_backend_card(self, c: _pb.Card) -> None:
         self._render_output = None
         self._note = None
         self.id = c.id
@@ -86,7 +86,7 @@ class Card:
         self._bugcheck()
         hooks.card_will_flush(self)
         # mtime & usn are set by backend
-        card = BackendCard(
+        card = _pb.Card(
             id=self.id,
             note_id=self.nid,
             deck_id=self.did,
diff --git a/pylib/anki/collection.py b/pylib/anki/collection.py
index 5ea9a876c..5666184e2 100644
--- a/pylib/anki/collection.py
+++ b/pylib/anki/collection.py
@@ -4,51 +4,66 @@
 from __future__ import annotations
 
 import copy
+import enum
 import os
 import pprint
 import re
 import time
 import traceback
 import weakref
+from dataclasses import dataclass
 from typing import TYPE_CHECKING, Any, List, Optional, Sequence, Tuple, Union
 
-import anki.backend_pb2 as pb
+import anki._backend.backend_pb2 as _pb
 import anki.find
 import anki.latex  # sets up hook
 import anki.template
 from anki import hooks
-from anki.backend_pb2 import SearchTerm
+from anki._backend import (  # pylint: disable=unused-import
+    ConcatSeparator,
+    FormatTimeSpanContext,
+    RustBackend,
+)
+
+# from anki._backend import _SyncStatus as SyncStatus
 from anki.cards import Card
 from anki.config import ConfigManager
 from anki.consts import *
 from anki.dbproxy import DBProxy
 from anki.decks import DeckManager
-from anki.errors import AnkiError
+from anki.errors import AnkiError, DBError
+from anki.lang import TR
 from anki.media import MediaManager, media_paths_from_col_path
 from anki.models import ModelManager
 from anki.notes import Note
-from anki.rsbackend import (  # pylint: disable=unused-import
-    TR,
-    ConcatSeparator,
-    DBError,
-    FormatTimeSpanContext,
-    InvalidInput,
-    Progress,
-    RustBackend,
-    from_json_bytes,
-    pb,
-)
 from anki.sched import Scheduler as V1Scheduler
 from anki.schedv2 import Scheduler as V2Scheduler
 from anki.tags import TagManager
-from anki.utils import devMode, ids2str, intTime, splitFields, stripHTMLMedia
+from anki.utils import (
+    devMode,
+    from_json_bytes,
+    ids2str,
+    intTime,
+    splitFields,
+    stripHTMLMedia,
+)
 
-ConfigBoolKey = pb.ConfigBool.Key  # pylint: disable=no-member
+# public exports
+SearchTerm = _pb.SearchTerm
+MediaSyncProgress = _pb.MediaSyncProgress
+FullSyncProgress = _pb.FullSyncProgress
+NormalSyncProgress = _pb.NormalSyncProgress
+DatabaseCheckProgress = _pb.DatabaseCheckProgress
+ConfigBoolKey = _pb.ConfigBool.Key  # pylint: disable=no-member
+EmptyCardsReport = _pb.EmptyCardsReport
+NoteWithEmptyCards = _pb.NoteWithEmptyCards
+GraphPreferences = _pb.GraphPreferences
 
+# pylint: disable=no-member
 if TYPE_CHECKING:
-    from anki.rsbackend import FormatTimeSpanContextValue, TRValue
+    from anki.lang import FormatTimeSpanContextValue, TRValue
 
-    ConfigBoolKeyValue = pb.ConfigBool.KeyValue  # pylint: disable=no-member
+    ConfigBoolKeyValue = _pb.ConfigBool.KeyValue
 
 
 class Collection:
@@ -394,6 +409,9 @@ class Collection:
     def set_deck(self, card_ids: List[int], deck_id: int) -> None:
         self.backend.set_deck(card_ids=card_ids, deck_id=deck_id)
 
+    def get_empty_cards(self) -> EmptyCardsReport:
+        return self.backend.get_empty_cards()
+
     # legacy
 
     def remCards(self, ids: List[int], notes: bool = True) -> None:
@@ -445,20 +463,20 @@ class Collection:
         order: Union[
             bool,
             str,
-            pb.BuiltinSearchOrder.BuiltinSortKindValue,  # pylint: disable=no-member
+            _pb.BuiltinSearchOrder.BuiltinSortKindValue,  # pylint: disable=no-member
         ] = False,
         reverse: bool = False,
     ) -> Sequence[int]:
         if isinstance(order, str):
-            mode = pb.SortOrder(custom=order)
+            mode = _pb.SortOrder(custom=order)
         elif isinstance(order, bool):
             if order is True:
-                mode = pb.SortOrder(from_config=pb.Empty())
+                mode = _pb.SortOrder(from_config=_pb.Empty())
             else:
-                mode = pb.SortOrder(none=pb.Empty())
+                mode = _pb.SortOrder(none=_pb.Empty())
         else:
-            mode = pb.SortOrder(
-                builtin=pb.BuiltinSearchOrder(kind=order, reverse=reverse)
+            mode = _pb.SortOrder(
+                builtin=_pb.BuiltinSearchOrder(kind=order, reverse=reverse)
             )
         return self.backend.search_cards(search=query, order=mode)
 
@@ -603,6 +621,19 @@ table.review-log {{ {revlog_style} }}
     def studied_today(self) -> str:
         return self.backend.studied_today()
 
+    def graph_data(self, search: str, days: int) -> bytes:
+        return self.backend.graphs(search=search, days=days)
+
+    def get_graph_preferences(self) -> bytes:
+        return self.backend.get_graph_preferences()
+
+    def set_graph_preferences(self, prefs: GraphPreferences) -> None:
+        self.backend.set_graph_preferences(input=prefs)
+
+    def congrats_info(self) -> bytes:
+        "Don't use this, it will likely go away in the future."
+        return self.backend.congrats_info().SerializeToString()
+
     # legacy
 
     def cardStats(self, card: Card) -> str:
@@ -797,5 +828,42 @@ table.review-log {{ {revlog_style} }}
         )
 
 
+class ProgressKind(enum.Enum):
+    NoProgress = 0
+    MediaSync = 1
+    MediaCheck = 2
+    FullSync = 3
+    NormalSync = 4
+    DatabaseCheck = 5
+
+
+@dataclass
+class Progress:
+    kind: ProgressKind
+    val: Union[
+        MediaSyncProgress,
+        FullSyncProgress,
+        NormalSyncProgress,
+        DatabaseCheckProgress,
+        str,
+    ]
+
+    @staticmethod
+    def from_proto(proto: _pb.Progress) -> Progress:
+        kind = proto.WhichOneof("value")
+        if kind == "media_sync":
+            return Progress(kind=ProgressKind.MediaSync, val=proto.media_sync)
+        elif kind == "media_check":
+            return Progress(kind=ProgressKind.MediaCheck, val=proto.media_check)
+        elif kind == "full_sync":
+            return Progress(kind=ProgressKind.FullSync, val=proto.full_sync)
+        elif kind == "normal_sync":
+            return Progress(kind=ProgressKind.NormalSync, val=proto.normal_sync)
+        elif kind == "database_check":
+            return Progress(kind=ProgressKind.DatabaseCheck, val=proto.database_check)
+        else:
+            return Progress(kind=ProgressKind.NoProgress, val="")
+
+
 # legacy name
 _Collection = Collection
diff --git a/pylib/anki/config.py b/pylib/anki/config.py
index 55cfcf585..bad5a804f 100644
--- a/pylib/anki/config.py
+++ b/pylib/anki/config.py
@@ -23,7 +23,8 @@ import weakref
 from typing import Any
 
 import anki
-from anki.rsbackend import NotFoundError, from_json_bytes, to_json_bytes
+from anki.errors import NotFoundError
+from anki.utils import from_json_bytes, to_json_bytes
 
 
 class ConfigManager:
diff --git a/pylib/anki/consts.py b/pylib/anki/consts.py
index 6ff036b1e..18c134ea2 100644
--- a/pylib/anki/consts.py
+++ b/pylib/anki/consts.py
@@ -6,7 +6,7 @@ from __future__ import annotations
 from typing import Any, Dict, Optional
 
 import anki
-from anki.rsbackend import TR
+from anki.lang import TR
 
 # whether new cards should be mixed with reviews, or shown first or last
 NEW_CARDS_DISTRIBUTE = 0
diff --git a/pylib/anki/dbproxy.py b/pylib/anki/dbproxy.py
index 1a9c024ff..7ec126e04 100644
--- a/pylib/anki/dbproxy.py
+++ b/pylib/anki/dbproxy.py
@@ -21,7 +21,7 @@ class DBProxy:
     # Lifecycle
     ###############
 
-    def __init__(self, backend: anki.rsbackend.RustBackend) -> None:
+    def __init__(self, backend: anki._backend.RustBackend) -> None:
         self._backend = backend
         self.mod = False
         self.last_begin_at = 0
diff --git a/pylib/anki/decks.py b/pylib/anki/decks.py
index d3acfe4dc..d50c4b611 100644
--- a/pylib/anki/decks.py
+++ b/pylib/anki/decks.py
@@ -8,17 +8,14 @@ import pprint
 from typing import Any, Dict, Iterable, List, Optional, Sequence, Tuple, Union
 
 import anki  # pylint: disable=unused-import
-import anki.backend_pb2 as pb
+import anki._backend.backend_pb2 as _pb
 from anki.consts import *
-from anki.errors import DeckRenameError
-from anki.rsbackend import (
-    TR,
-    DeckTreeNode,
-    NotFoundError,
-    from_json_bytes,
-    to_json_bytes,
-)
-from anki.utils import ids2str, intTime
+from anki.errors import DeckIsFilteredError, DeckRenameError, NotFoundError
+from anki.utils import from_json_bytes, ids2str, intTime, to_json_bytes
+
+# public exports
+DeckTreeNode = _pb.DeckTreeNode
+DeckNameID = _pb.DeckNameID
 
 # legacy code may pass this in as the type argument to .id()
 defaultDeck = 0
@@ -139,7 +136,7 @@ class DeckManager:
 
     def all_names_and_ids(
         self, skip_empty_default=False, include_filtered=True
-    ) -> Sequence[pb.DeckNameID]:
+    ) -> Sequence[DeckNameID]:
         "A sorted sequence of deck names and IDs."
         return self.col.backend.get_deck_names(
             skip_empty_default=skip_empty_default, include_filtered=include_filtered
@@ -166,7 +163,7 @@ class DeckManager:
     def new_deck_legacy(self, filtered: bool) -> Deck:
         return from_json_bytes(self.col.backend.new_deck_legacy(filtered))
 
-    def deck_tree(self) -> pb.DeckTreeNode:
+    def deck_tree(self) -> DeckTreeNode:
         return self.col.backend.deck_tree(top_deck_id=0, now=0)
 
     @classmethod
@@ -250,7 +247,7 @@ class DeckManager:
             g["id"] = self.col.backend.add_or_update_deck_legacy(
                 deck=to_json_bytes(g), preserve_usn_and_mtime=preserve_usn
             )
-        except anki.rsbackend.DeckIsFilteredError as exc:
+        except DeckIsFilteredError as exc:
             raise DeckRenameError("deck was filtered") from exc
 
     def rename(self, g: Deck, newName: str) -> None:
diff --git a/pylib/anki/errors.py b/pylib/anki/errors.py
index 4bfc9aa24..bed39fab0 100644
--- a/pylib/anki/errors.py
+++ b/pylib/anki/errors.py
@@ -1,8 +1,92 @@
 # Copyright: Ankitects Pty Ltd and contributors
 # License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
+from __future__ import annotations
+
 from typing import Any
 
+import anki._backend.backend_pb2 as _pb
+
+# fixme: notfounderror etc need to be in rsbackend.py
+
+
+class StringError(Exception):
+    def __str__(self) -> str:
+        return self.args[0]  # pylint: disable=unsubscriptable-object
+
+
+class Interrupted(Exception):
+    pass
+
+
+class NetworkError(StringError):
+    pass
+
+
+class SyncError(StringError):
+    # pylint: disable=no-member
+    def is_auth_error(self) -> bool:
+        return self.args[1] == _pb.SyncError.SyncErrorKind.AUTH_FAILED
+
+
+class IOError(StringError):
+    pass
+
+
+class DBError(StringError):
+    pass
+
+
+class TemplateError(StringError):
+    pass
+
+
+class NotFoundError(Exception):
+    pass
+
+
+class ExistsError(Exception):
+    pass
+
+
+class DeckIsFilteredError(Exception):
+    pass
+
+
+class InvalidInput(StringError):
+    pass
+
+
+def backend_exception_to_pylib(err: _pb.BackendError) -> Exception:
+    val = err.WhichOneof("value")
+    if val == "interrupted":
+        return Interrupted()
+    elif val == "network_error":
+        return NetworkError(err.localized, err.network_error.kind)
+    elif val == "sync_error":
+        return SyncError(err.localized, err.sync_error.kind)
+    elif val == "io_error":
+        return IOError(err.localized)
+    elif val == "db_error":
+        return DBError(err.localized)
+    elif val == "template_parse":
+        return TemplateError(err.localized)
+    elif val == "invalid_input":
+        return InvalidInput(err.localized)
+    elif val == "json_error":
+        return StringError(err.localized)
+    elif val == "not_found_error":
+        return NotFoundError()
+    elif val == "exists":
+        return ExistsError()
+    elif val == "deck_is_filtered":
+        return DeckIsFilteredError()
+    elif val == "proto_error":
+        return StringError(err.localized)
+    else:
+        print("unhandled error type:", val)
+        return StringError(err.localized)
+
 
 class AnkiError(Exception):
     def __init__(self, type, **data) -> None:
diff --git a/pylib/anki/exporting.py b/pylib/anki/exporting.py
index 1d2fd4a13..13c66cdda 100644
--- a/pylib/anki/exporting.py
+++ b/pylib/anki/exporting.py
@@ -13,7 +13,7 @@ from zipfile import ZipFile
 
 from anki import hooks
 from anki.collection import Collection
-from anki.rsbackend import TR
+from anki.lang import TR
 from anki.utils import ids2str, namedtmp, splitFields, stripHTML
 
 
diff --git a/pylib/anki/fluent_pb2.pyi b/pylib/anki/fluent_pb2.pyi
deleted file mode 120000
index a8cb14b62..000000000
--- a/pylib/anki/fluent_pb2.pyi
+++ /dev/null
@@ -1 +0,0 @@
-../../bazel-bin/pylib/anki/fluent_pb2.pyi
\ No newline at end of file
diff --git a/pylib/anki/importing/__init__.py b/pylib/anki/importing/__init__.py
index 03e645c30..ec7e05080 100644
--- a/pylib/anki/importing/__init__.py
+++ b/pylib/anki/importing/__init__.py
@@ -7,8 +7,7 @@ from anki.importing.csvfile import TextImporter
 from anki.importing.mnemo import MnemosyneImporter
 from anki.importing.pauker import PaukerImporter
 from anki.importing.supermemo_xml import SupermemoXmlImporter  # type: ignore
-from anki.lang import tr_legacyglobal
-from anki.rsbackend import TR
+from anki.lang import TR, tr_legacyglobal
 
 Importers = (
     (tr_legacyglobal(TR.IMPORTING_TEXT_SEPARATED_BY_TABS_OR_SEMICOLONS), TextImporter),
diff --git a/pylib/anki/importing/anki2.py b/pylib/anki/importing/anki2.py
index 6eb6a9c59..5c1bbec6b 100644
--- a/pylib/anki/importing/anki2.py
+++ b/pylib/anki/importing/anki2.py
@@ -9,7 +9,7 @@ from anki.collection import Collection
 from anki.consts import *
 from anki.decks import DeckManager
 from anki.importing.base import Importer
-from anki.rsbackend import TR
+from anki.lang import TR
 from anki.utils import intTime, joinFields, splitFields
 
 GUID = 1
diff --git a/pylib/anki/importing/csvfile.py b/pylib/anki/importing/csvfile.py
index eeee98d46..081553f18 100644
--- a/pylib/anki/importing/csvfile.py
+++ b/pylib/anki/importing/csvfile.py
@@ -7,7 +7,7 @@ from typing import Any, List, Optional, TextIO, Union
 
 from anki.collection import Collection
 from anki.importing.noteimp import ForeignNote, NoteImporter
-from anki.rsbackend import TR
+from anki.lang import TR
 
 
 class TextImporter(NoteImporter):
diff --git a/pylib/anki/importing/mnemo.py b/pylib/anki/importing/mnemo.py
index ed798ecab..f3cafedbd 100644
--- a/pylib/anki/importing/mnemo.py
+++ b/pylib/anki/importing/mnemo.py
@@ -7,7 +7,7 @@ from typing import cast
 
 from anki.db import DB
 from anki.importing.noteimp import ForeignCard, ForeignNote, NoteImporter
-from anki.rsbackend import TR
+from anki.lang import TR
 from anki.stdmodels import addBasicModel, addClozeModel
 
 
diff --git a/pylib/anki/importing/noteimp.py b/pylib/anki/importing/noteimp.py
index d90c18dfb..e3617330b 100644
--- a/pylib/anki/importing/noteimp.py
+++ b/pylib/anki/importing/noteimp.py
@@ -7,7 +7,7 @@ from typing import Dict, List, Optional, Tuple, Union
 from anki.collection import Collection
 from anki.consts import NEW_CARDS_RANDOM, STARTING_FACTOR
 from anki.importing.base import Importer
-from anki.rsbackend import TR
+from anki.lang import TR
 from anki.utils import (
     fieldChecksum,
     guid64,
diff --git a/pylib/anki/lang.py b/pylib/anki/lang.py
index 54dc5e06c..2cc2eb8ed 100644
--- a/pylib/anki/lang.py
+++ b/pylib/anki/lang.py
@@ -5,9 +5,20 @@ from __future__ import annotations
 
 import locale
 import re
-from typing import Optional, Tuple
+from typing import TYPE_CHECKING, Optional, Tuple
 
 import anki
+import anki._backend.backend_pb2 as _pb
+import anki._backend.fluent_pb2 as _fluent_pb
+
+# public exports
+TR = _fluent_pb.FluentString
+FormatTimeSpanContext = _pb.FormatTimespanIn.Context  # pylint: disable=no-member
+
+# pylint: disable=no-member
+if TYPE_CHECKING:
+    TRValue = _fluent_pb.FluentStringValue
+    FormatTimeSpanContextValue = _pb.FormatTimespanIn.ContextValue
 
 langs = sorted(
     [
@@ -142,7 +153,7 @@ def lang_to_disk_lang(lang: str) -> str:
 currentLang = "en"
 
 # the current Fluent translation instance
-current_i18n: Optional[anki.rsbackend.RustBackend] = None
+current_i18n: Optional[anki._backend.RustBackend] = None
 
 # path to locale folder
 locale_folder = ""
@@ -169,7 +180,7 @@ def tr_legacyglobal(*args, **kwargs) -> str:
 def set_lang(lang: str, locale_dir: str) -> None:
     global currentLang, current_i18n, locale_folder
     currentLang = lang
-    current_i18n = anki.rsbackend.RustBackend(ftl_folder=locale_folder, langs=[lang])
+    current_i18n = anki._backend.RustBackend(ftl_folder=locale_folder, langs=[lang])
     locale_folder = locale_dir
 
 
diff --git a/pylib/anki/latex.py b/pylib/anki/latex.py
index 782502eb9..4fb5138e8 100644
--- a/pylib/anki/latex.py
+++ b/pylib/anki/latex.py
@@ -10,9 +10,10 @@ from dataclasses import dataclass
 from typing import Any, List, Optional, Tuple
 
 import anki
+import anki._backend.backend_pb2 as _pb
 from anki import hooks
+from anki.lang import TR
 from anki.models import NoteType
-from anki.rsbackend import TR, pb
 from anki.template import TemplateRenderContext, TemplateRenderOutput
 from anki.utils import call, isMac, namedtmp, tmpdir
 
@@ -45,7 +46,7 @@ class ExtractedLatexOutput:
     latex: List[ExtractedLatex]
 
     @staticmethod
-    def from_proto(proto: pb.ExtractLatexOut) -> ExtractedLatexOutput:
+    def from_proto(proto: _pb.ExtractLatexOut) -> ExtractedLatexOutput:
         return ExtractedLatexOutput(
             html=proto.text,
             latex=[
diff --git a/pylib/anki/media.py b/pylib/anki/media.py
index 2d9a2478e..c31789237 100644
--- a/pylib/anki/media.py
+++ b/pylib/anki/media.py
@@ -14,9 +14,9 @@ import urllib.request
 from typing import Any, Callable, List, Optional, Tuple
 
 import anki
+import anki._backend.backend_pb2 as _pb
 from anki.consts import *
 from anki.latex import render_latex, render_latex_returning_errors
-from anki.rsbackend import pb
 from anki.utils import intTime
 
 
@@ -26,6 +26,9 @@ def media_paths_from_col_path(col_path: str) -> Tuple[str, str]:
     return (media_folder, media_db)
 
 
+CheckMediaOut = _pb.CheckMediaOut
+
+
 # fixme: look into whether we can drop chdir() below
 # - need to check aa89d06304fecd3597da4565330a3e55bdbb91fe
 # - and audio handling code
@@ -188,7 +191,7 @@ class MediaManager:
     # Checking media
     ##########################################################################
 
-    def check(self) -> pb.CheckMediaOut:
+    def check(self) -> CheckMediaOut:
         output = self.col.backend.check_media()
         # files may have been renamed on disk, so an undo at this point could
         # break file references
diff --git a/pylib/anki/models.py b/pylib/anki/models.py
index 5f8351246..2a8e29b26 100644
--- a/pylib/anki/models.py
+++ b/pylib/anki/models.py
@@ -9,17 +9,24 @@ import time
 from typing import Any, Dict, List, Optional, Sequence, Tuple, Union
 
 import anki  # pylint: disable=unused-import
-import anki.backend_pb2 as pb
+import anki._backend.backend_pb2 as _pb
 from anki.consts import *
-from anki.lang import without_unicode_isolation
-from anki.rsbackend import (
-    TR,
-    NotFoundError,
-    StockNoteType,
+from anki.errors import NotFoundError
+from anki.lang import TR, without_unicode_isolation
+from anki.utils import (
+    checksum,
     from_json_bytes,
+    ids2str,
+    intTime,
+    joinFields,
+    splitFields,
     to_json_bytes,
 )
-from anki.utils import checksum, ids2str, intTime, joinFields, splitFields
+
+# public exports
+NoteTypeNameID = _pb.NoteTypeNameID
+NoteTypeNameIDUseCount = _pb.NoteTypeNameIDUseCount
+
 
 # types
 NoteType = Dict[str, Any]
@@ -121,10 +128,10 @@ class ModelManager:
     # Listing note types
     #############################################################
 
-    def all_names_and_ids(self) -> Sequence[pb.NoteTypeNameID]:
+    def all_names_and_ids(self) -> Sequence[NoteTypeNameID]:
         return self.col.backend.get_notetype_names()
 
-    def all_use_counts(self) -> Sequence[pb.NoteTypeNameIDUseCount]:
+    def all_use_counts(self) -> Sequence[NoteTypeNameIDUseCount]:
         return self.col.backend.get_notetype_names_and_counts()
 
     # legacy
@@ -200,7 +207,7 @@ class ModelManager:
         # caller should call save() after modifying
         nt = from_json_bytes(
             self.col.backend.get_stock_notetype_legacy(
-                StockNoteType.STOCK_NOTE_TYPE_BASIC
+                _pb.StockNoteType.STOCK_NOTE_TYPE_BASIC
             )
         )
         nt["flds"] = []
@@ -293,7 +300,7 @@ class ModelManager:
         assert isinstance(name, str)
         nt = from_json_bytes(
             self.col.backend.get_stock_notetype_legacy(
-                StockNoteType.STOCK_NOTE_TYPE_BASIC
+                _pb.StockNoteType.STOCK_NOTE_TYPE_BASIC
             )
         )
         field = nt["flds"][0]
@@ -354,7 +361,7 @@ class ModelManager:
     def new_template(self, name: str) -> Template:
         nt = from_json_bytes(
             self.col.backend.get_stock_notetype_legacy(
-                StockNoteType.STOCK_NOTE_TYPE_BASIC
+                _pb.StockNoteType.STOCK_NOTE_TYPE_BASIC
             )
         )
         template = nt["tmpls"][0]
@@ -508,5 +515,5 @@ and notes.mid = ? and cards.ord = ?""",
         self, m: NoteType, flds: str, allowEmpty: bool = True
     ) -> List[int]:
         print("_availClozeOrds() is deprecated; use note.cloze_numbers_in_fields()")
-        note = anki.rsbackend.BackendNote(fields=[flds])
+        note = anki._backend.BackendNote(fields=[flds])
         return list(self.col.backend.cloze_numbers_in_note(note))
diff --git a/pylib/anki/notes.py b/pylib/anki/notes.py
index 80d86b6cf..0cf0ff3f3 100644
--- a/pylib/anki/notes.py
+++ b/pylib/anki/notes.py
@@ -7,9 +7,9 @@ import pprint
 from typing import Any, List, Optional, Sequence, Tuple
 
 import anki  # pylint: disable=unused-import
+import anki._backend.backend_pb2 as _pb
 from anki import hooks
 from anki.models import NoteType
-from anki.rsbackend import BackendNote
 from anki.utils import joinFields
 
 
@@ -41,7 +41,7 @@ class Note:
         assert n
         self._load_from_backend_note(n)
 
-    def _load_from_backend_note(self, n: BackendNote) -> None:
+    def _load_from_backend_note(self, n: _pb.Note) -> None:
         self.id = n.id
         self.guid = n.guid
         self.mid = n.notetype_id
@@ -51,9 +51,9 @@ class Note:
         self.fields = list(n.fields)
         self._fmap = self.col.models.fieldMap(self.model())
 
-    def to_backend_note(self) -> BackendNote:
+    def to_backend_note(self) -> _pb.Note:
         hooks.note_will_flush(self)
-        return BackendNote(
+        return _pb.Note(
             id=self.id,
             guid=self.guid,
             notetype_id=self.mid,
diff --git a/pylib/anki/rsbackend_gen.py b/pylib/anki/rsbackend_gen.py
deleted file mode 120000
index b247575fd..000000000
--- a/pylib/anki/rsbackend_gen.py
+++ /dev/null
@@ -1 +0,0 @@
-../../bazel-bin/pylib/anki/rsbackend_gen.py
\ No newline at end of file
diff --git a/pylib/anki/schedv2.py b/pylib/anki/schedv2.py
index 86c5073cd..d9a0a21dc 100644
--- a/pylib/anki/schedv2.py
+++ b/pylib/anki/schedv2.py
@@ -20,30 +20,25 @@ from typing import (
 )
 
 import anki  # pylint: disable=unused-import
-import anki.backend_pb2 as pb
+import anki._backend.backend_pb2 as _pb
 from anki import hooks
+from anki._backend import CountsForDeckToday, FormatTimeSpanContext, SchedTimingToday
 from anki.cards import Card
 from anki.consts import *
-from anki.decks import Deck, DeckConfig, DeckManager, QueueConfig
+from anki.decks import Deck, DeckConfig, DeckManager, DeckTreeNode, QueueConfig
 from anki.notes import Note
-from anki.rsbackend import (
-    TR,
-    CountsForDeckToday,
-    DeckTreeNode,
-    FormatTimeSpanContext,
-    SchedTimingToday,
-    from_json_bytes,
-)
-from anki.utils import ids2str, intTime
+from anki.utils import from_json_bytes, ids2str, intTime
 
-UnburyCurrentDeckMode = pb.UnburyCardsInCurrentDeckIn.Mode  # pylint:disable=no-member
-BuryOrSuspendMode = pb.BuryOrSuspendCardsIn.Mode  # pylint:disable=no-member
+CongratsInfoOut = anki._backend.backend_pb2.CongratsInfoOut
+
+UnburyCurrentDeckMode = _pb.UnburyCardsInCurrentDeckIn.Mode  # pylint:disable=no-member
+BuryOrSuspendMode = _pb.BuryOrSuspendCardsIn.Mode  # pylint:disable=no-member
 if TYPE_CHECKING:
     UnburyCurrentDeckModeValue = (
-        pb.UnburyCardsInCurrentDeckIn.ModeValue  # pylint:disable=no-member
+        _pb.UnburyCardsInCurrentDeckIn.ModeValue  # pylint:disable=no-member
     )
     BuryOrSuspendModeValue = (
-        pb.BuryOrSuspendCardsIn.ModeValue  # pylint:disable=no-member
+        _pb.BuryOrSuspendCardsIn.ModeValue  # pylint:disable=no-member
     )
 
 # card types: 0=new, 1=lrn, 2=rev, 3=relrn
@@ -1241,7 +1236,7 @@ due = (case when odue>0 then odue else due end), odue = 0, odid = 0, usn = ? whe
     # Deck finished state
     ##########################################################################
 
-    def congratulations_info(self) -> pb.CongratsInfoOut:
+    def congratulations_info(self) -> CongratsInfoOut:
         return self.col.backend.congrats_info()
 
     def finishedMsg(self) -> str:
diff --git a/pylib/anki/stats.py b/pylib/anki/stats.py
index 164b5516d..0fb451ea1 100644
--- a/pylib/anki/stats.py
+++ b/pylib/anki/stats.py
@@ -10,7 +10,7 @@ from typing import Any, Dict, List, Optional, Sequence, Tuple, Union
 
 import anki
 from anki.consts import *
-from anki.rsbackend import TR, FormatTimeSpanContext
+from anki.lang import TR, FormatTimeSpanContext
 from anki.utils import ids2str
 
 # Card stats
diff --git a/pylib/anki/stdmodels.py b/pylib/anki/stdmodels.py
index e4db1eaf6..32c4c4bb5 100644
--- a/pylib/anki/stdmodels.py
+++ b/pylib/anki/stdmodels.py
@@ -5,12 +5,15 @@ from __future__ import annotations
 
 from typing import TYPE_CHECKING, Callable, List, Tuple
 
+from anki._backend import StockNoteType
 from anki.collection import Collection
 from anki.models import NoteType
-from anki.rsbackend import StockNoteType, from_json_bytes
+from anki.utils import from_json_bytes
 
 if TYPE_CHECKING:
-    from anki.backend_pb2 import StockNoteTypeValue  # pylint: disable=no-name-in-module
+    from anki._backend.backend_pb2 import (  # pylint: disable=no-name-in-module
+        StockNoteTypeValue,
+    )
 
 
 # add-on authors can add ("note type name", function_like_addBasicModel)
diff --git a/pylib/anki/sync.py b/pylib/anki/sync.py
index 9bd6409b5..331902280 100644
--- a/pylib/anki/sync.py
+++ b/pylib/anki/sync.py
@@ -1,8 +1,15 @@
 # Copyright: Ankitects Pty Ltd and contributors
 # License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
-#
+
+import anki._backend.backend_pb2 as _pb
+
+# public exports
+SyncAuth = _pb.SyncAuth
+SyncOutput = _pb.SyncCollectionOut
+SyncStatus = _pb.SyncStatusOut
+
+
 # Legacy attributes some add-ons may be using
-#
 
 from .httpclient import HttpClient
 
diff --git a/pylib/anki/syncserver/__init__.py b/pylib/anki/syncserver/__init__.py
index 1d2db82db..04d5c10ce 100644
--- a/pylib/anki/syncserver/__init__.py
+++ b/pylib/anki/syncserver/__init__.py
@@ -26,7 +26,7 @@ except ImportError as e:
 from flask import Response
 
 from anki import Collection
-from anki.backend_pb2 import SyncServerMethodIn
+from anki._backend.backend_pb2 import SyncServerMethodIn
 
 Method = SyncServerMethodIn.Method  # pylint: disable=no-member
 
diff --git a/pylib/anki/tags.py b/pylib/anki/tags.py
index c8e969568..bfcd8c9a5 100644
--- a/pylib/anki/tags.py
+++ b/pylib/anki/tags.py
@@ -16,9 +16,13 @@ import re
 from typing import Collection, List, Optional, Sequence, Tuple
 
 import anki  # pylint: disable=unused-import
-from anki.collection import SearchTerm
+import anki._backend.backend_pb2 as _pb
+import anki.collection
 from anki.utils import ids2str
 
+# public exports
+TagTreeNode = _pb.TagTreeNode
+
 
 class TagManager:
     def __init__(self, col: anki.collection.Collection) -> None:
@@ -37,6 +41,9 @@ class TagManager:
     def allItems(self) -> List[Tuple[str, int]]:
         return [(t.name, t.usn) for t in self.col.backend.all_tags()]
 
+    def tree(self) -> TagTreeNode:
+        return self.col.backend.tag_tree()
+
     # Registering and fetching tags
     #############################################################
 
@@ -87,7 +94,7 @@ class TagManager:
 
     def rename_tag(self, old: str, new: str) -> int:
         "Rename provided tag, returning number of changed notes."
-        nids = self.col.find_notes(SearchTerm(tag=old))
+        nids = self.col.find_notes(anki.collection.SearchTerm(tag=old))
         if not nids:
             return 0
         escaped_name = re.sub(r"[*_\\]", r"\\\g<0>", old)
diff --git a/pylib/anki/template.py b/pylib/anki/template.py
index 0050f4c24..535d0c80f 100644
--- a/pylib/anki/template.py
+++ b/pylib/anki/template.py
@@ -32,13 +32,15 @@ from dataclasses import dataclass
 from typing import Any, Dict, List, Optional, Sequence, Tuple, Union
 
 import anki
+import anki._backend.backend_pb2 as _pb
 from anki import hooks
 from anki.cards import Card
 from anki.decks import DeckManager
+from anki.errors import TemplateError
 from anki.models import NoteType
 from anki.notes import Note
-from anki.rsbackend import pb, to_json_bytes
 from anki.sound import AVTag, SoundOrVideoTag, TTSTag
+from anki.utils import to_json_bytes
 
 CARD_BLANK_HELP = (
     "https://anki.tenderapp.com/kb/card-appearance/the-front-of-this-card-is-blank"
@@ -61,7 +63,7 @@ class PartiallyRenderedCard:
     anodes: TemplateReplacementList
 
     @classmethod
-    def from_proto(cls, out: pb.RenderCardOut) -> PartiallyRenderedCard:
+    def from_proto(cls, out: _pb.RenderCardOut) -> PartiallyRenderedCard:
         qnodes = cls.nodes_from_proto(out.question_nodes)
         anodes = cls.nodes_from_proto(out.answer_nodes)
 
@@ -69,7 +71,7 @@ class PartiallyRenderedCard:
 
     @staticmethod
     def nodes_from_proto(
-        nodes: Sequence[pb.RenderedTemplateNode],
+        nodes: Sequence[_pb.RenderedTemplateNode],
     ) -> TemplateReplacementList:
         results: TemplateReplacementList = []
         for node in nodes:
@@ -86,7 +88,7 @@ class PartiallyRenderedCard:
         return results
 
 
-def av_tag_to_native(tag: pb.AVTag) -> AVTag:
+def av_tag_to_native(tag: _pb.AVTag) -> AVTag:
     val = tag.WhichOneof("value")
     if val == "sound_or_video":
         return SoundOrVideoTag(filename=tag.sound_or_video)
@@ -100,7 +102,7 @@ def av_tag_to_native(tag: pb.AVTag) -> AVTag:
         )
 
 
-def av_tags_to_native(tags: Sequence[pb.AVTag]) -> List[AVTag]:
+def av_tags_to_native(tags: Sequence[_pb.AVTag]) -> List[AVTag]:
     return list(map(av_tag_to_native, tags))
 
 
@@ -206,7 +208,7 @@ class TemplateRenderContext:
     def render(self) -> TemplateRenderOutput:
         try:
             partial = self._partially_render()
-        except anki.rsbackend.TemplateError as e:
+        except TemplateError as e:
             return TemplateRenderOutput(
                 question_text=str(e),
                 answer_text=str(e),
diff --git a/pylib/anki/utils.py b/pylib/anki/utils.py
index d65971224..d8d3975ab 100644
--- a/pylib/anki/utils.py
+++ b/pylib/anki/utils.py
@@ -26,6 +26,17 @@ from anki.dbproxy import DBProxy
 
 _tmpdir: Optional[str]
 
+try:
+    # pylint: disable=c-extension-no-member
+    import orjson
+
+    to_json_bytes = orjson.dumps
+    from_json_bytes = orjson.loads
+except:
+    print("orjson is missing; DB operations will be slower")
+    to_json_bytes = lambda obj: json.dumps(obj).encode("utf8")  # type: ignore
+    from_json_bytes = json.loads
+
 # Time handling
 ##############################################################################
 
diff --git a/pylib/tests/test_collection.py b/pylib/tests/test_collection.py
index 601ca9dc2..00824bebd 100644
--- a/pylib/tests/test_collection.py
+++ b/pylib/tests/test_collection.py
@@ -5,8 +5,7 @@ import tempfile
 
 from anki import Collection as aopen
 from anki.dbproxy import emulate_named_args
-from anki.lang import without_unicode_isolation
-from anki.rsbackend import TR
+from anki.lang import TR, without_unicode_isolation
 from anki.stdmodels import addBasicModel, get_stock_notetypes
 from anki.utils import isWin
 from tests.shared import assertException, getEmptyCol
diff --git a/pylib/tests/test_find.py b/pylib/tests/test_find.py
index 9cbc5a46b..114ec635d 100644
--- a/pylib/tests/test_find.py
+++ b/pylib/tests/test_find.py
@@ -1,9 +1,9 @@
 # coding: utf-8
 import pytest
 
+from anki._backend import BuiltinSortKind
 from anki.collection import ConfigBoolKey
 from anki.consts import *
-from anki.rsbackend import BuiltinSortKind
 from tests.shared import getEmptyCol, isNearCutoff
 
 
diff --git a/pylib/tests/test_models.py b/pylib/tests/test_models.py
index a5c2aafcb..47e6cf55f 100644
--- a/pylib/tests/test_models.py
+++ b/pylib/tests/test_models.py
@@ -2,7 +2,7 @@
 import time
 
 from anki.consts import MODEL_CLOZE
-from anki.rsbackend import NotFoundError
+from anki.errors import NotFoundError
 from anki.utils import isWin, stripHTML
 from tests.shared import getEmptyCol
 
diff --git a/pylib/tools/BUILD.bazel b/pylib/tools/BUILD.bazel
index 25b2277cb..f2a4fa2d6 100644
--- a/pylib/tools/BUILD.bazel
+++ b/pylib/tools/BUILD.bazel
@@ -22,20 +22,6 @@ py_binary(
     ],
 )
 
-py_binary(
-    name = "genbackend",
-    srcs = [
-        "genbackend.py",
-        "//pylib/anki:backend_pb2",
-    ],
-    visibility = ["//pylib:__subpackages__"],
-    deps = [
-        requirement("black"),
-        requirement("stringcase"),
-        requirement("protobuf"),
-    ],
-)
-
 py_library(
     name = "hookslib",
     srcs = ["hookslib.py"],
diff --git a/qt/aqt/__init__.py b/qt/aqt/__init__.py
index 61d3c91d1..350a24446 100644
--- a/qt/aqt/__init__.py
+++ b/qt/aqt/__init__.py
@@ -14,8 +14,8 @@ from typing import Any, Callable, Dict, Optional, Union
 
 import anki.lang
 from anki import version as _version
+from anki._backend import RustBackend
 from anki.consts import HELP_SITE
-from anki.rsbackend import RustBackend
 from anki.utils import checksum, isLin, isMac
 from aqt.qt import *
 from aqt.utils import TR, locale_dir, tr
diff --git a/qt/aqt/browser.py b/qt/aqt/browser.py
index 5b29e646b..2465191da 100644
--- a/qt/aqt/browser.py
+++ b/qt/aqt/browser.py
@@ -13,8 +13,9 @@ from typing import List, Optional, Sequence, Tuple, cast
 import aqt
 import aqt.forms
 from anki.cards import Card
-from anki.collection import Collection, ConfigBoolKey, InvalidInput, SearchTerm
+from anki.collection import Collection, ConfigBoolKey, SearchTerm
 from anki.consts import *
+from anki.errors import InvalidInput
 from anki.lang import without_unicode_isolation
 from anki.models import NoteType
 from anki.notes import Note
diff --git a/qt/aqt/clayout.py b/qt/aqt/clayout.py
index 1b82e62c3..0fc9fb3d9 100644
--- a/qt/aqt/clayout.py
+++ b/qt/aqt/clayout.py
@@ -9,9 +9,9 @@ from typing import Any, Dict, List, Optional
 import aqt
 from anki.cards import Card
 from anki.consts import *
+from anki.errors import TemplateError
 from anki.lang import without_unicode_isolation
 from anki.notes import Note
-from anki.rsbackend import TemplateError
 from anki.template import TemplateRenderContext
 from aqt import AnkiQt, gui_hooks
 from aqt.qt import *
diff --git a/qt/aqt/dbcheck.py b/qt/aqt/dbcheck.py
index 864ffffec..ad46bf231 100644
--- a/qt/aqt/dbcheck.py
+++ b/qt/aqt/dbcheck.py
@@ -4,7 +4,7 @@
 from __future__ import annotations
 
 import aqt
-from anki.rsbackend import DatabaseCheckProgress, ProgressKind
+from anki.collection import DatabaseCheckProgress, ProgressKind
 from aqt.qt import *
 from aqt.utils import showText, tooltip
 
diff --git a/qt/aqt/deckbrowser.py b/qt/aqt/deckbrowser.py
index b585ddfaf..10041e9fb 100644
--- a/qt/aqt/deckbrowser.py
+++ b/qt/aqt/deckbrowser.py
@@ -9,8 +9,8 @@ from dataclasses import dataclass
 from typing import Any
 
 import aqt
+from anki.decks import DeckTreeNode
 from anki.errors import DeckRenameError
-from anki.rsbackend import DeckTreeNode
 from aqt import AnkiQt, gui_hooks
 from aqt.qt import *
 from aqt.sound import av_player
diff --git a/qt/aqt/dyndeckconf.py b/qt/aqt/dyndeckconf.py
index c9d0d6338..12b5180d4 100644
--- a/qt/aqt/dyndeckconf.py
+++ b/qt/aqt/dyndeckconf.py
@@ -4,7 +4,8 @@
 from typing import List, Optional
 
 import aqt
-from anki.collection import InvalidInput, SearchTerm
+from anki.collection import SearchTerm
+from anki.errors import InvalidInput
 from anki.lang import without_unicode_isolation
 from aqt.qt import *
 from aqt.utils import (
diff --git a/qt/aqt/emptycards.py b/qt/aqt/emptycards.py
index e399ce1da..b9e94d8de 100644
--- a/qt/aqt/emptycards.py
+++ b/qt/aqt/emptycards.py
@@ -6,7 +6,7 @@ from __future__ import annotations
 import re
 
 import aqt
-from anki.backend_pb2 import EmptyCardsReport, NoteWithEmptyCards
+from anki.collection import EmptyCardsReport, NoteWithEmptyCards
 from aqt import gui_hooks
 from aqt.qt import QDialog, QDialogButtonBox, qconnect
 from aqt.utils import TR, disable_help_button, restoreGeom, saveGeom, tooltip, tr
@@ -24,7 +24,7 @@ def show_empty_cards(mw: aqt.main.AnkiQt) -> None:
         diag = EmptyCardsDialog(mw, report)
         diag.show()
 
-    mw.taskman.run_in_background(mw.col.backend.get_empty_cards, on_done)
+    mw.taskman.run_in_background(mw.col.get_empty_cards, on_done)
 
 
 class EmptyCardsDialog(QDialog):
diff --git a/qt/aqt/fields.py b/qt/aqt/fields.py
index 9c676ffe7..2cf6170ba 100644
--- a/qt/aqt/fields.py
+++ b/qt/aqt/fields.py
@@ -3,9 +3,9 @@
 
 import aqt
 from anki.consts import *
+from anki.errors import TemplateError
 from anki.lang import without_unicode_isolation
 from anki.models import NoteType
-from anki.rsbackend import TemplateError
 from aqt import AnkiQt, gui_hooks
 from aqt.qt import *
 from aqt.schema_change_tracker import ChangeTracker
diff --git a/qt/aqt/main.py b/qt/aqt/main.py
index 2653e11de..173d7a4d8 100644
--- a/qt/aqt/main.py
+++ b/qt/aqt/main.py
@@ -26,11 +26,11 @@ import aqt.stats
 import aqt.toolbar
 import aqt.webview
 from anki import hooks
+from anki._backend import RustBackend as _RustBackend
 from anki.collection import Collection, SearchTerm
 from anki.decks import Deck
 from anki.hooks import runHook
 from anki.lang import without_unicode_isolation
-from anki.rsbackend import RustBackend
 from anki.sound import AVTag, SoundOrVideoTag
 from anki.utils import devMode, ids2str, intTime, isMac, isWin, splitFields
 from aqt import gui_hooks
@@ -100,7 +100,7 @@ class AnkiQt(QMainWindow):
         self,
         app: QApplication,
         profileManager: ProfileManagerType,
-        backend: RustBackend,
+        backend: _RustBackend,
         opts: Namespace,
         args: List[Any],
     ) -> None:
diff --git a/qt/aqt/mediacheck.py b/qt/aqt/mediacheck.py
index 50bf66f0e..79a560632 100644
--- a/qt/aqt/mediacheck.py
+++ b/qt/aqt/mediacheck.py
@@ -9,8 +9,10 @@ from concurrent.futures import Future
 from typing import Iterable, List, Optional, Sequence, TypeVar
 
 import aqt
-from anki.collection import SearchTerm
-from anki.rsbackend import TR, Interrupted, ProgressKind, pb
+from anki.collection import ProgressKind, SearchTerm
+from anki.errors import Interrupted
+from anki.lang import TR
+from anki.media import CheckMediaOut
 from aqt.qt import *
 from aqt.utils import (
     askUser,
@@ -74,7 +76,7 @@ class MediaChecker:
 
         self.mw.taskman.run_on_main(lambda: self.mw.progress.update(progress.val))
 
-    def _check(self) -> pb.CheckMediaOut:
+    def _check(self) -> CheckMediaOut:
         "Run the check on a background thread."
         return self.mw.col.media.check()
 
@@ -87,7 +89,7 @@ class MediaChecker:
         if isinstance(exc, Interrupted):
             return
 
-        output: pb.CheckMediaOut = future.result()
+        output: CheckMediaOut = future.result()
         report = output.report
 
         # show report and offer to delete
diff --git a/qt/aqt/mediasrv.py b/qt/aqt/mediasrv.py
index b37282afc..1da2565ae 100644
--- a/qt/aqt/mediasrv.py
+++ b/qt/aqt/mediasrv.py
@@ -18,11 +18,10 @@ import flask_cors  # type: ignore
 from flask import Response, request
 from waitress.server import create_server
 
-import anki.backend_pb2 as pb
 import aqt
 from anki import hooks
-from anki.rsbackend import from_json_bytes
-from anki.utils import devMode
+from anki.collection import GraphPreferences
+from anki.utils import devMode, from_json_bytes
 from aqt.qt import *
 from aqt.utils import aqt_data_folder
 
@@ -253,22 +252,21 @@ def _redirectWebExports(path):
 
 def graph_data() -> bytes:
     args = from_json_bytes(request.data)
-    return aqt.mw.col.backend.graphs(search=args["search"], days=args["days"])
+    return aqt.mw.col.graph_data(search=args["search"], days=args["days"])
 
 
 def graph_preferences() -> bytes:
-    return aqt.mw.col.backend.get_graph_preferences()
+    return aqt.mw.col.get_graph_preferences()
 
 
 def set_graph_preferences() -> None:
-    input = pb.GraphPreferences()
-    input.ParseFromString(request.data)
-    aqt.mw.col.backend.set_graph_preferences(input=input)
+    prefs = GraphPreferences()
+    prefs.ParseFromString(request.data)
+    aqt.mw.col.set_graph_preferences(prefs)
 
 
 def congrats_info() -> bytes:
-    info = aqt.mw.col.backend.congrats_info()
-    return info.SerializeToString()
+    return aqt.mw.col.congrats_info()
 
 
 post_handlers = {
diff --git a/qt/aqt/mediasync.py b/qt/aqt/mediasync.py
index 07925f132..3e60a3e9e 100644
--- a/qt/aqt/mediasync.py
+++ b/qt/aqt/mediasync.py
@@ -9,13 +9,9 @@ from dataclasses import dataclass
 from typing import Callable, List, Optional, Union
 
 import aqt
-from anki.rsbackend import (
-    TR,
-    Interrupted,
-    MediaSyncProgress,
-    NetworkError,
-    ProgressKind,
-)
+from anki.collection import MediaSyncProgress, ProgressKind
+from anki.errors import Interrupted, NetworkError
+from anki.lang import TR
 from anki.types import assert_exhaustive
 from anki.utils import intTime
 from aqt import gui_hooks
diff --git a/qt/aqt/models.py b/qt/aqt/models.py
index 1d238a496..bc398a5ba 100644
--- a/qt/aqt/models.py
+++ b/qt/aqt/models.py
@@ -6,11 +6,9 @@ from typing import Any, List, Optional, Sequence
 
 import aqt.clayout
 from anki import stdmodels
-from anki.backend_pb2 import NoteTypeNameIDUseCount
 from anki.lang import without_unicode_isolation
-from anki.models import NoteType
+from anki.models import NoteType, NoteTypeNameIDUseCount
 from anki.notes import Note
-from anki.rsbackend import pb
 from aqt import AnkiQt, gui_hooks
 from aqt.qt import *
 from aqt.utils import (
@@ -51,7 +49,7 @@ class Models(QDialog):
             self.form.buttonBox.helpRequested,
             lambda: openHelp(HelpPage.ADDING_A_NOTE_TYPE),
         )
-        self.models: List[pb.NoteTypeNameIDUseCount] = []
+        self.models: List[NoteTypeNameIDUseCount] = []
         self.setupModels()
         restoreGeom(self, "models")
         self.exec_()
@@ -111,7 +109,7 @@ class Models(QDialog):
             self.saveAndRefresh(nt)
 
     def saveAndRefresh(self, nt: NoteType) -> None:
-        def save() -> Sequence[pb.NoteTypeNameIDUseCount]:
+        def save() -> Sequence[NoteTypeNameIDUseCount]:
             self.mm.save(nt)
             return self.col.models.all_use_counts()
 
@@ -161,7 +159,7 @@ class Models(QDialog):
 
         nt = self.current_notetype()
 
-        def save() -> Sequence[pb.NoteTypeNameIDUseCount]:
+        def save() -> Sequence[NoteTypeNameIDUseCount]:
             self.mm.rem(nt)
             return self.col.models.all_use_counts()
 
diff --git a/qt/aqt/profiles.py b/qt/aqt/profiles.py
index 93065846d..af548c5c3 100644
--- a/qt/aqt/profiles.py
+++ b/qt/aqt/profiles.py
@@ -20,7 +20,7 @@ import aqt.sound
 from anki import Collection
 from anki.db import DB
 from anki.lang import without_unicode_isolation
-from anki.rsbackend import SyncAuth
+from anki.sync import SyncAuth
 from anki.utils import intTime, isMac, isWin
 from aqt import appHelpSite
 from aqt.qt import *
diff --git a/qt/aqt/sidebar.py b/qt/aqt/sidebar.py
index 6806107b1..c1c3749ad 100644
--- a/qt/aqt/sidebar.py
+++ b/qt/aqt/sidebar.py
@@ -9,9 +9,10 @@ from enum import Enum
 from typing import TYPE_CHECKING, Dict, Iterable, List, Optional, Sequence, Tuple, cast
 
 import aqt
-from anki.collection import ConfigBoolKey, InvalidInput, SearchTerm
-from anki.errors import DeckRenameError
-from anki.rsbackend import DeckTreeNode, TagTreeNode
+from anki.collection import ConfigBoolKey, SearchTerm
+from anki.decks import DeckTreeNode
+from anki.errors import DeckRenameError, InvalidInput
+from anki.tags import TagTreeNode
 from aqt import gui_hooks
 from aqt.main import ResetReason
 from aqt.models import Models
@@ -524,7 +525,7 @@ class SidebarTreeView(QTreeView):
                 newhead = head + node.name + "::"
                 render(item, node.children, newhead)
 
-        tree = self.col.backend.tag_tree()
+        tree = self.col.tags.tree()
         root = self._section_root(
             root=root,
             name=TR.BROWSING_SIDEBAR_TAGS,
diff --git a/qt/aqt/sync.py b/qt/aqt/sync.py
index 691fde1f4..c71ae132c 100644
--- a/qt/aqt/sync.py
+++ b/qt/aqt/sync.py
@@ -8,18 +8,10 @@ import os
 from typing import Callable, Tuple
 
 import aqt
-from anki.lang import without_unicode_isolation
-from anki.rsbackend import (
-    TR,
-    FullSyncProgress,
-    Interrupted,
-    NormalSyncProgress,
-    ProgressKind,
-    SyncError,
-    SyncErrorKind,
-    SyncOutput,
-    SyncStatus,
-)
+from anki.collection import FullSyncProgress, NormalSyncProgress, ProgressKind
+from anki.errors import Interrupted, SyncError
+from anki.lang import TR, without_unicode_isolation
+from anki.sync import SyncOutput, SyncStatus
 from anki.utils import platDesc
 from aqt.qt import (
     QDialog,
@@ -69,7 +61,7 @@ def get_sync_status(mw: aqt.main.AnkiQt, callback: Callable[[SyncStatus], None])
 
 def handle_sync_error(mw: aqt.main.AnkiQt, err: Exception):
     if isinstance(err, SyncError):
-        if err.kind() == SyncErrorKind.AUTH_FAILED:
+        if err.is_auth_error():
             mw.pm.clear_sync_auth()
     elif isinstance(err, Interrupted):
         # no message to show
@@ -249,7 +241,7 @@ def sync_login(
         try:
             auth = fut.result()
         except SyncError as e:
-            if e.kind() == SyncErrorKind.AUTH_FAILED:
+            if e.is_auth_error():
                 showWarning(str(e))
                 sync_login(mw, on_success, username, password)
             else:
diff --git a/qt/aqt/toolbar.py b/qt/aqt/toolbar.py
index 8214966e2..8bc71904d 100644
--- a/qt/aqt/toolbar.py
+++ b/qt/aqt/toolbar.py
@@ -6,7 +6,7 @@ from __future__ import annotations
 from typing import Any, Dict, Optional
 
 import aqt
-from anki.rsbackend import SyncStatus
+from anki.sync import SyncStatus
 from aqt import gui_hooks
 from aqt.qt import *
 from aqt.sync import get_sync_status
diff --git a/qt/aqt/utils.py b/qt/aqt/utils.py
index 373d2bc46..ac511e9a4 100644
--- a/qt/aqt/utils.py
+++ b/qt/aqt/utils.py
@@ -14,13 +14,14 @@ from markdown import markdown
 
 import anki
 import aqt
-from anki.rsbackend import TR, InvalidInput  # pylint: disable=unused-import
+from anki.errors import InvalidInput
+from anki.lang import TR  # pylint: disable=unused-import
 from anki.utils import invalidFilename, isMac, isWin, noBundledLibs, versionWithBuild
 from aqt.qt import *
 from aqt.theme import theme_manager
 
 if TYPE_CHECKING:
-    from anki.rsbackend import TRValue
+    from anki.lang import TRValue
 
     TextFormat = Union[Literal["plain", "rich"]]
 
diff --git a/qt/tests/test_i18n.py b/qt/tests/test_i18n.py
index c11180032..41f9c26e4 100644
--- a/qt/tests/test_i18n.py
+++ b/qt/tests/test_i18n.py
@@ -1,5 +1,5 @@
 import anki.lang
-from anki.rsbackend import TR
+from anki.lang import TR
 
 
 def test_no_collection_i18n():