diff --git a/pylib/anki/collection.py b/pylib/anki/collection.py
index 9e93c3d53..01845a74b 100644
--- a/pylib/anki/collection.py
+++ b/pylib/anki/collection.py
@@ -166,8 +166,6 @@ decks from col"""
         )
         self.decks.decks = self.backend.get_all_decks()
         self.decks.changed = False
-        self.models.models = self.backend.get_all_notetypes()
-        self.models.changed = False
 
     def setMod(self) -> None:
         """Mark DB modified.
@@ -232,6 +230,7 @@ crt=?, mod=?, scm=?, dty=?, usn=?, ls=?""",
                 self.save(trx=False)
             else:
                 self.db.rollback()
+            self.models._clear_cache()
             self.backend.close_collection(downgrade=downgrade)
             self.db = None
             self.media.close()
@@ -319,21 +318,12 @@ crt=?, mod=?, scm=?, dty=?, usn=?, ls=?""",
         "Return a new note with the current model."
         return Note(self, self.models.current(forDeck))
 
+    def add_note(self, note: Note, deck_id: int) -> None:
+        note.id = self.backend.add_note(note.to_backend_note(), deck_id)
+
     def addNote(self, note: Note) -> int:
-        """Add a note to the collection. Return number of new cards."""
-        # check we have card models available, then save
-        cms = self.findTemplates(note)
-        if not cms:
-            return 0
-        note.flush()
-        # deck conf governs which of these are used
-        due = self.nextID("pos")
-        # add cards
-        ncards = 0
-        for template in cms:
-            self._newCard(note, template, due)
-            ncards += 1
-        return ncards
+        self.add_note(note, note.model()["did"])
+        return len(note.cards())
 
     def remNotes(self, ids: Iterable[int]) -> None:
         """Deletes notes with the given IDs."""
diff --git a/pylib/anki/exporting.py b/pylib/anki/exporting.py
index 300d4c97b..0114f2c65 100644
--- a/pylib/anki/exporting.py
+++ b/pylib/anki/exporting.py
@@ -226,7 +226,7 @@ class AnkiExporter(Exporter):
             # need to reset card state
             self.dst.sched.resetCards(cids)
         # models - start with zero
-        self.dst.models.models = {}
+        self.dst.models.remove_all_notetypes()
         for m in self.src.models.all():
             if int(m["id"]) in mids:
                 self.dst.models.update(m)
diff --git a/pylib/anki/media.py b/pylib/anki/media.py
index dbfddd8fb..410298b7f 100644
--- a/pylib/anki/media.py
+++ b/pylib/anki/media.py
@@ -10,7 +10,7 @@ import time
 import urllib.error
 import urllib.parse
 import urllib.request
-from typing import Any, Callable, List, Optional, Tuple, Union
+from typing import Any, Callable, List, Optional, Tuple
 
 import anki
 from anki.consts import *
@@ -122,7 +122,7 @@ class MediaManager:
     ##########################################################################
 
     def filesInStr(
-        self, mid: Union[int, str], string: str, includeRemote: bool = False
+        self, mid: int, string: str, includeRemote: bool = False
     ) -> List[str]:
         l = []
         model = self.col.models.get(mid)
diff --git a/pylib/anki/models.py b/pylib/anki/models.py
index 0759f7a98..47c2aeb2b 100644
--- a/pylib/anki/models.py
+++ b/pylib/anki/models.py
@@ -6,9 +6,10 @@ from __future__ import annotations
 import copy
 import re
 import time
-from typing import Any, Callable, Dict, List, Optional, Tuple, Union
+from typing import Any, Dict, List, Optional, Tuple, Union
 
 import anki  # pylint: disable=unused-import
+import anki.backend_pb2 as pb
 from anki import hooks
 from anki.consts import *
 from anki.lang import _
@@ -23,12 +24,16 @@ TemplateRequirementType = str  # Union["all", "any", "none"]
 TemplateRequiredFieldOrds = Tuple[int, TemplateRequirementType, List[int]]
 AllTemplateReqs = List[TemplateRequiredFieldOrds]
 
+# fixme: memory leaks
+# fixme: syncing, beforeUpload
+
 # Models
 ##########################################################################
 
 # - careful not to add any lists/dicts/etc here, as they aren't deep copied
 
 defaultModel: NoteType = {
+    "id": 0,
     "sortf": 0,
     "did": 1,
     "latexPre": """\
@@ -43,7 +48,7 @@ defaultModel: NoteType = {
     "latexPost": "\\end{document}",
     "mod": 0,
     "usn": 0,
-    "vers": [],  # FIXME: remove when other clients have caught up
+    "req": [],
     "type": MODEL_STD,
     "css": """\
 .card {
@@ -83,50 +88,131 @@ defaultTemplate: Template = {
 }
 
 
-class ModelManager:
-    models: Dict[str, NoteType]
+class ModelsDictProxy:
+    def __init__(self, col: anki.storage._Collection):
+        self._col = col.weakref()
 
+    def _warn(self):
+        print("add-on should use methods on col.models, not col.models.models dict")
+
+    def __getitem__(self, item):
+        self._warn()
+        return self._col.models.get(int(item))
+
+    def __setitem__(self, key, val):
+        self._warn()
+        self._col.models.save(val)
+
+    def __len__(self):
+        self._warn()
+        return len(self._col.models.all_names_and_ids())
+
+    def keys(self):
+        self._warn()
+        return [str(nt.id) for nt in self._col.models.all_names_and_ids()]
+
+    def values(self):
+        self._warn()
+        return self._col.models.all()
+
+    def items(self):
+        self._warn()
+        return [(str(nt["id"]), nt) for nt in self._col.models.all()]
+
+    def __contains__(self, item):
+        self._warn()
+        self._col.models.have(item)
+
+
+class ModelManager:
     # Saving/loading registry
     #############################################################
 
     def __init__(self, col: anki.storage._Collection) -> None:
         self.col = col.weakref()
-        self.models = {}
-        self.changed = False
+        self.models = ModelsDictProxy(col)
+        # do not access this directly!
+        self._cache = {}
 
     def save(
         self,
-        m: Optional[NoteType] = None,
+        m: NoteType = None,
+        # no longer used
         templates: bool = False,
         updateReqs: bool = True,
     ) -> None:
-        "Mark M modified if provided, and schedule registry flush."
-        if m and m["id"]:
-            m["mod"] = intTime()
-            m["usn"] = self.col.usn()
-            if updateReqs:
-                self._updateRequired(m)
-            if templates:
-                self._syncTemplates(m)
-        self.changed = True
+        "Save changes made to provided note type."
+        if not m:
+            print("col.models.save() should be passed the changed notetype")
+            return
+
+        self.update(m, preserve_usn=False)
+
+        # fixme: badly named; also fires on updates
         hooks.note_type_added(m)
 
+    # legacy
     def flush(self) -> None:
-        "Flush the registry if any models were changed."
-        if self.changed:
-            self.ensureNotEmpty()
-            self.col.backend.set_all_notetypes(self.models)
-            self.changed = False
+        pass
 
+    # fixme: enforce at lower level
     def ensureNotEmpty(self) -> Optional[bool]:
-        if not self.models:
+        if not self.all_names_and_ids():
             from anki.stdmodels import addBasicModel
 
             addBasicModel(self.col)
             return True
         return None
 
-    # Retrieving and creating models
+    # Caching
+    #############################################################
+    # A lot of existing code expects to be able to quickly and
+    # frequently obtain access to an entire notetype, so we currently
+    # need to cache responses from the backend. Please do not
+    # access the cache directly!
+
+    _cache: Dict[int, NoteType] = {}
+
+    def _update_cache(self, nt: NoteType) -> None:
+        self._cache[nt["id"]] = nt
+
+    def _remove_from_cache(self, ntid: int) -> None:
+        if ntid in self._cache:
+            del self._cache[ntid]
+
+    def _get_cached(self, ntid: int) -> Optional[NoteType]:
+        return self._cache.get(ntid)
+
+    def _clear_cache(self):
+        self._cache = {}
+
+    # Listing note types
+    #############################################################
+
+    def all_names_and_ids(self) -> List[pb.NoteTypeNameID]:
+        return self.col.backend.get_notetype_names_and_ids()
+
+    def all_use_counts(self) -> List[pb.NoteTypeNameIDUseCount]:
+        return self.col.backend.get_notetype_use_counts()
+
+    def id_for_name(self, name: str) -> Optional[int]:
+        return self.col.backend.get_notetype_id_by_name(name)
+
+    # legacy
+
+    def allNames(self) -> List[str]:
+        return [n.name for n in self.all_names_and_ids()]
+
+    def ids(self) -> List[int]:
+        return [n.id for n in self.all_names_and_ids()]
+
+    # only used by importing code
+    def have(self, id: int) -> bool:
+        if isinstance(id, str):
+            id = int(id)
+        return any(True for e in self.all_names_and_ids() if e.id == id)
+
+    # Current note type
     #############################################################
 
     def current(self, forDeck: bool = True) -> Any:
@@ -134,33 +220,46 @@ class ModelManager:
         m = self.get(self.col.decks.current().get("mid"))
         if not forDeck or not m:
             m = self.get(self.col.conf["curModel"])
-        return m or list(self.models.values())[0]
+        if m:
+            return m
+        return self.get(self.all_names_and_ids()[0].id)
 
     def setCurrent(self, m: NoteType) -> None:
         self.col.conf["curModel"] = m["id"]
         self.col.setMod()
 
-    def get(self, id: Any) -> Any:
+    # Retrieving and creating models
+    #############################################################
+
+    def get(self, id: int) -> Optional[NoteType]:
         "Get model with ID, or None."
-        id = str(id)
-        if id in self.models:
-            return self.models[id]
+        # deal with various legacy input types
+        if id is None:
+            return None
+        elif isinstance(id, str):
+            id = int(id)
 
-    def all(self) -> List:
+        nt = self._get_cached(id)
+        if not nt:
+            nt = self.col.backend.get_notetype_legacy(id)
+            if nt:
+                self._update_cache(nt)
+        return nt
+
+    def all(self) -> List[NoteType]:
         "Get all models."
-        return list(self.models.values())
+        return [self.get(nt.id) for nt in self.all_names_and_ids()]
 
-    def allNames(self) -> List:
-        return [m["name"] for m in self.all()]
-
-    def byName(self, name: str) -> Any:
+    def byName(self, name: str) -> Optional[NoteType]:
         "Get model with NAME."
-        for m in list(self.models.values()):
-            if m["name"] == name:
-                return m
+        id = self.id_for_name(name)
+        if id:
+            return self.get(id)
+        else:
+            return None
 
     def new(self, name: str) -> NoteType:
-        "Create a new model, save it in the registry, and return it."
+        "Create a new model, and return it."
         # caller should call save() after modifying
         m = defaultModel.copy()
         m["name"] = name
@@ -168,59 +267,50 @@ class ModelManager:
         m["flds"] = []
         m["tmpls"] = []
         m["tags"] = []
-        m["id"] = None
+        m["id"] = 0
         return m
 
     def rem(self, m: NoteType) -> None:
         "Delete model, and all its cards/notes."
+        self.remove(m["id"])
+
+    def remove_all_notetypes(self):
         self.col.modSchema(check=True)
-        current = self.current()["id"] == m["id"]
-        # delete notes/cards
-        self.col.remCards(
-            self.col.db.list(
-                """
-select id from cards where nid in (select id from notes where mid = ?)""",
-                m["id"],
-            )
-        )
-        # then the model
-        del self.models[str(m["id"])]
-        self.save()
-        # GUI should ensure last model is not deleted
-        if current:
-            self.setCurrent(list(self.models.values())[0])
+        for nt in self.all_names_and_ids():
+            self._remove_from_cache(nt.id)
+            self.col.backend.remove_notetype(nt.id)
+
+    def remove(self, id: int) -> None:
+        self.col.modSchema(check=True)
+        self._remove_from_cache(id)
+        was_current = self.current()["id"] == id
+        self.col.backend.remove_notetype(id)
+
+        # fixme: handle in backend
+        if was_current:
+            self.col.conf["curModel"] = self.all_names_and_ids()[0].id
 
     def add(self, m: NoteType) -> None:
-        self._setID(m)
-        self.update(m)
-        self.setCurrent(m)
         self.save(m)
 
     def ensureNameUnique(self, m: NoteType) -> None:
-        for mcur in self.all():
-            if mcur["name"] == m["name"] and mcur["id"] != m["id"]:
-                m["name"] += "-" + checksum(str(time.time()))[:5]
-                break
+        existing_id = self.id_for_name(m["name"])
+        if existing_id is not None and existing_id != m["id"]:
+            m["name"] += "-" + checksum(str(time.time()))[:5]
 
-    def update(self, m: NoteType) -> None:
-        "Add or update an existing model. Used for syncing and merging."
+    def update(self, m: NoteType, preserve_usn=True) -> None:
+        "Add or update an existing model. Use .save() instead."
+        self._remove_from_cache(m["id"])
         self.ensureNameUnique(m)
-        self.models[str(m["id"])] = m
-        # mark registry changed, but don't bump mod time
-        self.save()
+        self.col.backend.add_or_update_notetype(m, preserve_usn=preserve_usn)
+        self.setCurrent(m)
+        self._mutate_after_write(m)
 
-    def _setID(self, m: NoteType) -> None:
-        while 1:
-            id = str(intTime(1000))
-            if id not in self.models:
-                break
-        m["id"] = id
-
-    def have(self, id: int) -> bool:
-        return str(id) in self.models
-
-    def ids(self) -> List[str]:
-        return list(self.models.keys())
+    def _mutate_after_write(self, nt: NoteType) -> None:
+        # existing code expects the note type to be mutated to reflect
+        # the changes made when adding, such as ordinal assignment :-(
+        updated = self.get(nt["id"])
+        nt.update(updated)
 
     # Tools
     ##################################################
@@ -231,17 +321,9 @@ select id from cards where nid in (select id from notes where mid = ?)""",
 
     def useCount(self, m: NoteType) -> Any:
         "Number of note using M."
+        print("useCount() is slow; prefer all_use_counts()")
         return self.col.db.scalar("select count() from notes where mid = ?", m["id"])
 
-    def tmplUseCount(self, m: NoteType, ord) -> Any:
-        return self.col.db.scalar(
-            """
-select count() from cards, notes where cards.nid = notes.id
-and notes.mid = ? and cards.ord = ?""",
-            m["id"],
-            ord,
-        )
-
     # Copying
     ##################################################
 
@@ -249,18 +331,13 @@ and notes.mid = ? and cards.ord = ?""",
         "Copy, save and return."
         m2 = copy.deepcopy(m)
         m2["name"] = _("%s copy") % m2["name"]
+        m2["id"] = 0
         self.add(m2)
         return m2
 
     # Fields
     ##################################################
 
-    def newField(self, name: str) -> Field:
-        assert isinstance(name, str)
-        f = defaultField.copy()
-        f["name"] = name
-        return f
-
     def fieldMap(self, m: NoteType) -> Dict[str, Tuple[int, Field]]:
         "Mapping of field name -> (ord, field)."
         return dict((f["name"], (f["ord"], f)) for f in m["flds"])
@@ -274,111 +351,55 @@ and notes.mid = ? and cards.ord = ?""",
     def setSortIdx(self, m: NoteType, idx: int) -> None:
         assert 0 <= idx < len(m["flds"])
         self.col.modSchema(check=True)
-        m["sortf"] = idx
-        self.col.updateFieldCache(self.nids(m))
-        self.save(m, updateReqs=False)
 
-    def addField(self, m: NoteType, field: Field) -> None:
-        # only mod schema if model isn't new
-        if m["id"]:
-            self.col.modSchema(check=True)
-        m["flds"].append(field)
-        self._updateFieldOrds(m)
+        m["sortf"] = idx
+
         self.save(m)
 
-        def add(fields):
-            fields.append("")
-            return fields
+    # Adding & changing fields
+    ##################################################
 
-        self._transformFields(m, add)
+    def newField(self, name: str) -> Field:
+        assert isinstance(name, str)
+        f = defaultField.copy()
+        f["name"] = name
+        return f
+
+    def addField(self, m: NoteType, field: Field) -> None:
+        if m["id"]:
+            self.col.modSchema(check=True)
+
+        m["flds"].append(field)
+
+        if m["id"]:
+            self.save(m)
 
     def remField(self, m: NoteType, field: Field) -> None:
         self.col.modSchema(check=True)
-        # save old sort field
-        sortFldName = m["flds"][m["sortf"]]["name"]
-        idx = m["flds"].index(field)
+
         m["flds"].remove(field)
-        # restore old sort field if possible, or revert to first field
-        m["sortf"] = 0
-        for c, f in enumerate(m["flds"]):
-            if f["name"] == sortFldName:
-                m["sortf"] = c
-                break
-        self._updateFieldOrds(m)
 
-        def delete(fields):
-            del fields[idx]
-            return fields
-
-        self._transformFields(m, delete)
-        if m["flds"][m["sortf"]]["name"] != sortFldName:
-            # need to rebuild sort field
-            self.col.updateFieldCache(self.nids(m))
-        # saves
-        self.renameField(m, field, None)
+        self.save(m)
 
     def moveField(self, m: NoteType, field: Field, idx: int) -> None:
         self.col.modSchema(check=True)
         oldidx = m["flds"].index(field)
         if oldidx == idx:
             return
-        # remember old sort field
-        sortf = m["flds"][m["sortf"]]
-        # move
+
         m["flds"].remove(field)
         m["flds"].insert(idx, field)
-        # restore sort field
-        m["sortf"] = m["flds"].index(sortf)
-        self._updateFieldOrds(m)
-        self.save(m, updateReqs=False)
 
-        def move(fields, oldidx=oldidx):
-            val = fields[oldidx]
-            del fields[oldidx]
-            fields.insert(idx, val)
-            return fields
-
-        self._transformFields(m, move)
-
-    def renameField(self, m: NoteType, field: Field, newName: Optional[str]) -> None:
-        self.col.modSchema(check=True)
-        if newName is not None:
-            newName = newName.replace(":", "")
-        pat = r"{{([^{}]*)([:#^/]|[^:#/^}][^:}]*?:|)%s}}"
-
-        def wrap(txt):
-            def repl(match):
-                return "{{" + match.group(1) + match.group(2) + txt + "}}"
-
-            return repl
-
-        for t in m["tmpls"]:
-            for fmt in ("qfmt", "afmt"):
-                if newName:
-                    t[fmt] = re.sub(
-                        pat % re.escape(field["name"]), wrap(newName), t[fmt]
-                    )
-                else:
-                    t[fmt] = re.sub(pat % re.escape(field["name"]), "", t[fmt])
-        field["name"] = newName
         self.save(m)
 
-    def _updateFieldOrds(self, m: NoteType) -> None:
-        for c, f in enumerate(m["flds"]):
-            f["ord"] = c
+    def renameField(self, m: NoteType, field: Field, newName: str) -> None:
+        assert field in m["flds"]
 
-    def _transformFields(self, m: NoteType, fn: Callable) -> None:
-        # model hasn't been added yet?
-        if not m["id"]:
-            return
-        r = []
-        for (id, flds) in self.col.db.execute(
-            "select id, flds from notes where mid = ?", m["id"]
-        ):
-            r.append((joinFields(fn(splitFields(flds))), intTime(), self.col.usn(), id))
-        self.col.db.executemany("update notes set flds=?,mod=?,usn=? where id = ?", r)
+        field["name"] = newName
 
-    # Templates
+        self.save(m)
+
+    # Adding & changing templates
     ##################################################
 
     def newTemplate(self, name: str) -> Template:
@@ -387,84 +408,33 @@ and notes.mid = ? and cards.ord = ?""",
         return t
 
     def addTemplate(self, m: NoteType, template: Template) -> None:
-        "Note: should col.genCards() afterwards."
         if m["id"]:
             self.col.modSchema(check=True)
+
         m["tmpls"].append(template)
-        self._updateTemplOrds(m)
-        self.save(m)
 
-    def remTemplate(self, m: NoteType, template: Template) -> bool:
-        "False if removing template would leave orphan notes."
+        if m["id"]:
+            self.save(m)
+
+    def remTemplate(self, m: NoteType, template: Template) -> None:
         assert len(m["tmpls"]) > 1
-        # find cards using this template
-        ord = m["tmpls"].index(template)
-        cids = self.col.db.list(
-            """
-select c.id from cards c, notes f where c.nid=f.id and mid = ? and ord = ?""",
-            m["id"],
-            ord,
-        )
-        # all notes with this template must have at least two cards, or we
-        # could end up creating orphaned notes
-        if self.col.db.scalar(
-            """
-select nid, count() from cards where
-nid in (select nid from cards where id in %s)
-group by nid
-having count() < 2
-limit 1"""
-            % ids2str(cids)
-        ):
-            return False
-        # ok to proceed; remove cards
         self.col.modSchema(check=True)
-        self.col.remCards(cids)
-        # shift ordinals
-        self.col.db.execute(
-            """
-update cards set ord = ord - 1, usn = ?, mod = ?
- where nid in (select id from notes where mid = ?) and ord > ?""",
-            self.col.usn(),
-            intTime(),
-            m["id"],
-            ord,
-        )
-        m["tmpls"].remove(template)
-        self._updateTemplOrds(m)
-        self.save(m)
-        return True
 
-    def _updateTemplOrds(self, m: NoteType) -> None:
-        for c, t in enumerate(m["tmpls"]):
-            t["ord"] = c
+        m["tmpls"].remove(template)
+
+        self.save(m)
 
     def moveTemplate(self, m: NoteType, template: Template, idx: int) -> None:
+        self.col.modSchema(check=True)
+
         oldidx = m["tmpls"].index(template)
         if oldidx == idx:
             return
-        oldidxs = dict((id(t), t["ord"]) for t in m["tmpls"])
+
         m["tmpls"].remove(template)
         m["tmpls"].insert(idx, template)
-        self._updateTemplOrds(m)
-        # generate change map
-        map = []
-        for t in m["tmpls"]:
-            map.append("when ord = %d then %d" % (oldidxs[id(t)], t["ord"]))
-        # apply
-        self.save(m, updateReqs=False)
-        self.col.db.execute(
-            """
-update cards set ord = (case %s end),usn=?,mod=? where nid in (
-select id from notes where mid = ?)"""
-            % " ".join(map),
-            self.col.usn(),
-            intTime(),
-            m["id"],
-        )
 
-    def _syncTemplates(self, m: NoteType) -> None:
-        rem = self.col.genCards(self.nids(m))
+        self.save(m)
 
     # Model changing
     ##########################################################################
diff --git a/pylib/anki/notes.py b/pylib/anki/notes.py
index 5d8a3ddee..a8f04d8d9 100644
--- a/pylib/anki/notes.py
+++ b/pylib/anki/notes.py
@@ -3,35 +3,19 @@
 
 from __future__ import annotations
 
-from typing import Any, Dict, List, Optional, Tuple
+from typing import Any, List, Optional, Tuple
 
 import anki  # pylint: disable=unused-import
 from anki import hooks
-from anki.models import Field, NoteType
-from anki.utils import (
-    fieldChecksum,
-    guid64,
-    intTime,
-    joinFields,
-    splitFields,
-    stripHTMLMedia,
-    timestampID,
-)
+from anki.models import NoteType
+from anki.rsbackend import BackendNote
+from anki.utils import fieldChecksum, joinFields, splitFields, stripHTMLMedia
 
 
 class Note:
-    col: anki.storage._Collection
-    newlyAdded: bool
-    id: int
-    guid: str
-    _model: NoteType
-    mid: int
-    tags: List[str]
-    fields: List[str]
-    flags: int
-    data: str
-    _fmap: Dict[str, Tuple[int, Field]]
-    scm: int
+    # not currently exposed
+    flags = 0
+    data = ""
 
     def __init__(
         self,
@@ -41,78 +25,51 @@ class Note:
     ) -> None:
         assert not (model and id)
         self.col = col.weakref()
-        self.newlyAdded = False
+        # self.newlyAdded = False
+
         if id:
+            # existing note
             self.id = id
             self.load()
         else:
-            self.id = timestampID(col.db, "notes")
-            self.guid = guid64()
-            self._model = model
-            self.mid = model["id"]
-            self.tags = []
-            self.fields = [""] * len(self._model["flds"])
-            self.flags = 0
-            self.data = ""
-            self._fmap = self.col.models.fieldMap(self._model)
-            self.scm = self.col.scm
+            # new note for provided notetype
+            self._load_from_backend_note(self.col.backend.new_note(model["id"]))
 
     def load(self) -> None:
-        (
-            self.guid,
-            self.mid,
-            self.mod,
-            self.usn,
-            tags,
-            fields,
-            self.flags,
-            self.data,
-        ) = self.col.db.first(
-            """
-select guid, mid, mod, usn, tags, flds, flags, data
-from notes where id = ?""",
-            self.id,
-        )
-        self.fields = splitFields(fields)
-        self.tags = self.col.tags.split(tags)
+        n = self.col.backend.get_note(self.id)
+        assert n
+        self._load_from_backend_note(n)
+
+    def _load_from_backend_note(self, n: BackendNote) -> None:
+        self.id = n.id
+        self.guid = n.guid
+        self.mid = n.ntid
+        self.mod = n.mtime_secs
+        self.usn = n.usn
+        self.tags = list(n.tags)
+        self.fields = list(n.fields)
+
         self._model = self.col.models.get(self.mid)
         self._fmap = self.col.models.fieldMap(self._model)
-        self.scm = self.col.scm
 
-    def flush(self, mod: Optional[int] = None) -> None:
-        "If fields or tags have changed, write changes to disk."
-        assert self.scm == self.col.scm
-        self._preFlush()
-        sfld = stripHTMLMedia(self.fields[self.col.models.sortIdx(self._model)])
-        tags = self.stringTags()
-        fields = self.joinedFields()
-        if not mod and self.col.db.scalar(
-            "select 1 from notes where id = ? and tags = ? and flds = ?",
-            self.id,
-            tags,
-            fields,
-        ):
-            return
-        csum = fieldChecksum(self.fields[0])
-        self.mod = mod if mod else intTime()
-        self.usn = self.col.usn()
-        res = self.col.db.execute(
-            """
-insert or replace into notes values (?,?,?,?,?,?,?,?,?,?,?)""",
-            self.id,
-            self.guid,
-            self.mid,
-            self.mod,
-            self.usn,
-            tags,
-            fields,
-            sfld,
-            csum,
-            self.flags,
-            self.data,
+    # fixme: only save tags in list on save
+    def to_backend_note(self) -> BackendNote:
+        hooks.note_will_flush(self)
+        return BackendNote(
+            id=self.id,
+            guid=self.guid,
+            ntid=self.mid,
+            mtime_secs=self.mod,
+            usn=self.usn,
+            # fixme: catch spaces in individual tags
+            tags=" ".join(self.tags).split(" "),
+            fields=self.fields,
         )
-        self.col.tags.register(self.tags)
-        self._postFlush()
+
+    def flush(self, mod=None) -> None:
+        # fixme: mod unused?
+        assert self.id != 0
+        self.col.backend.update_note(self.to_backend_note())
 
     def joinedFields(self) -> str:
         return joinFields(self.fields)
@@ -198,22 +155,3 @@ insert or replace into notes values (?,?,?,?,?,?,?,?,?,?,?)""",
             if stripHTMLMedia(splitFields(flds)[0]) == stripHTMLMedia(self.fields[0]):
                 return 2
         return False
-
-    # Flushing cloze notes
-    ##################################################
-
-    def _preFlush(self) -> None:
-        hooks.note_will_flush(self)
-        # have we been added yet?
-        self.newlyAdded = not self.col.db.scalar(
-            "select 1 from cards where nid = ?", self.id
-        )
-
-    def _postFlush(self) -> None:
-        # generate missing cards
-        if not self.newlyAdded:
-            rem = self.col.genCards([self.id])
-            # popping up a dialog while editing is confusing; instead we can
-            # document that the user should open the templates window to
-            # garbage collect empty cards
-            # self.col.remEmptyCards(ids)
diff --git a/pylib/anki/rsbackend.py b/pylib/anki/rsbackend.py
index 692fed2a5..8acca1811 100644
--- a/pylib/anki/rsbackend.py
+++ b/pylib/anki/rsbackend.py
@@ -47,6 +47,7 @@ assert ankirspy.buildhash() == anki.buildinfo.buildhash
 SchedTimingToday = pb.SchedTimingTodayOut
 BuiltinSortKind = pb.BuiltinSearchOrder.BuiltinSortKind
 BackendCard = pb.Card
+BackendNote = pb.Note
 TagUsnTuple = pb.TagUsnTuple
 NoteType = pb.NoteType
 
@@ -98,6 +99,10 @@ class TemplateError(StringError):
     pass
 
 
+class NotFoundError(Exception):
+    pass
+
+
 def proto_exception_to_native(err: pb.BackendError) -> Exception:
     val = err.WhichOneof("value")
     if val == "interrupted":
@@ -116,6 +121,8 @@ def proto_exception_to_native(err: pb.BackendError) -> Exception:
         return StringError(err.localized)
     elif val == "json_error":
         return StringError(err.localized)
+    elif val == "not_found_error":
+        return NotFoundError()
     else:
         assert_impossible_literal(val)
 
@@ -609,15 +616,12 @@ class RustBackend:
     def set_all_config(self, conf: Dict[str, Any]):
         self._run_command(pb.BackendInput(set_all_config=orjson.dumps(conf)))
 
-    def get_all_notetypes(self) -> Dict[str, Dict[str, Any]]:
+    def get_changed_notetypes(self, usn: int) -> Dict[str, Dict[str, Any]]:
         jstr = self._run_command(
-            pb.BackendInput(get_all_notetypes=pb.Empty())
-        ).get_all_notetypes
+            pb.BackendInput(get_changed_notetypes=usn)
+        ).get_changed_notetypes
         return orjson.loads(jstr)
 
-    def set_all_notetypes(self, nts: Dict[str, Dict[str, Any]]):
-        self._run_command(pb.BackendInput(set_all_notetypes=orjson.dumps(nts)))
-
     def get_all_decks(self) -> Dict[str, Dict[str, Any]]:
         jstr = self._run_command(
             pb.BackendInput(get_all_decks=pb.Empty())
@@ -634,6 +638,67 @@ class RustBackend:
             ).all_stock_notetypes.notetypes
         )
 
+    def get_notetype_names_and_ids(self) -> List[pb.NoteTypeNameID]:
+        return list(
+            self._run_command(
+                pb.BackendInput(get_notetype_names=pb.Empty())
+            ).get_notetype_names.entries
+        )
+
+    def get_notetype_use_counts(self) -> List[pb.NoteTypeNameIDUseCount]:
+        return list(
+            self._run_command(
+                pb.BackendInput(get_notetype_names_and_counts=pb.Empty())
+            ).get_notetype_names_and_counts.entries
+        )
+
+    def get_notetype_legacy(self, ntid: int) -> Optional[Dict]:
+        try:
+            bytes = self._run_command(
+                pb.BackendInput(get_notetype_legacy=ntid)
+            ).get_notetype_legacy
+        except NotFoundError:
+            return None
+        return orjson.loads(bytes)
+
+    def get_notetype_id_by_name(self, name: str) -> Optional[int]:
+        return (
+            self._run_command(
+                pb.BackendInput(get_notetype_id_by_name=name)
+            ).get_notetype_id_by_name
+            or None
+        )
+
+    def add_or_update_notetype(self, nt: Dict[str, Any], preserve_usn: bool) -> None:
+        bjson = orjson.dumps(nt)
+        id = self._run_command(
+            pb.BackendInput(
+                add_or_update_notetype=pb.AddOrUpdateNotetypeIn(
+                    json=bjson, preserve_usn_and_mtime=preserve_usn
+                )
+            )
+        ).add_or_update_notetype
+        nt["id"] = id
+
+    def remove_notetype(self, ntid: int) -> None:
+        self._run_command(pb.BackendInput(remove_notetype=ntid))
+
+    def new_note(self, ntid: int) -> BackendNote:
+        return self._run_command(pb.BackendInput(new_note=ntid)).new_note
+
+    def add_note(self, note: BackendNote, deck_id: int) -> int:
+        return self._run_command(
+            pb.BackendInput(add_note=pb.AddNoteIn(note=note, deck_id=deck_id))
+        ).add_note
+
+    def update_note(self, note: BackendNote) -> None:
+        self._run_command(pb.BackendInput(update_note=note))
+
+    def get_note(self, nid) -> Optional[BackendNote]:
+        try:
+            return self._run_command(pb.BackendInput(get_note=nid)).get_note
+        except NotFoundError:
+            return None
 
 def translate_string_in(
     key: TR, **kwargs: Union[str, int, float]
diff --git a/pylib/tests/test_cards.py b/pylib/tests/test_cards.py
index 6e519c84f..af1ddae58 100644
--- a/pylib/tests/test_cards.py
+++ b/pylib/tests/test_cards.py
@@ -69,6 +69,7 @@ def test_genrem():
     mm.save(m, templates=True)
     assert len(f.cards()) == 2
     # if the template is changed to remove cards, they'll be removed
+    t = m["tmpls"][1]
     t["qfmt"] = "{{Back}}"
     mm.save(m, templates=True)
     d.remCards(d.emptyCids())
diff --git a/pylib/tests/test_collection.py b/pylib/tests/test_collection.py
index cd47fced8..31be6bf6f 100644
--- a/pylib/tests/test_collection.py
+++ b/pylib/tests/test_collection.py
@@ -60,11 +60,6 @@ def test_noteAddDelete():
     t["afmt"] = "{{Front}}"
     mm.addTemplate(m, t)
     mm.save(m)
-    # the default save doesn't generate cards
-    assert deck.cardCount() == 1
-    # but when templates are edited such as in the card layout screen, it
-    # should generate cards on close
-    mm.save(m, templates=True, updateReqs=False)
     assert deck.cardCount() == 2
     # creating new notes should use both cards
     f = deck.newNote()
@@ -124,10 +119,10 @@ def test_addDelTags():
 
 def test_timestamps():
     deck = getEmptyCol()
-    assert len(deck.models.models) == len(models)
+    assert len(deck.models.all_names_and_ids()) == len(models)
     for i in range(100):
         addBasicModel(deck)
-    assert len(deck.models.models) == 100 + len(models)
+    assert len(deck.models.all_names_and_ids()) == 100 + len(models)
 
 
 def test_furigana():
diff --git a/pylib/tests/test_find.py b/pylib/tests/test_find.py
index 66f462c84..b8ea1c055 100644
--- a/pylib/tests/test_find.py
+++ b/pylib/tests/test_find.py
@@ -17,8 +17,8 @@ def test_findCards():
     f["Front"] = "dog"
     f["Back"] = "cat"
     f.tags.append("monkey animal_1 * %")
-    f1id = f.id
     deck.addNote(f)
+    f1id = f.id
     firstCardId = f.cards()[0].id
     f = deck.newNote()
     f["Front"] = "goats are fun"
@@ -32,6 +32,7 @@ def test_findCards():
     deck.addNote(f)
     catCard = f.cards()[0]
     m = deck.models.current()
+    m = deck.models.copy(m)
     mm = deck.models
     t = mm.newTemplate("Reverse")
     t["qfmt"] = "{{Back}}"
@@ -130,8 +131,8 @@ def test_findCards():
         != firstCardId
     )
     # model
-    assert len(deck.findCards("note:basic")) == 5
-    assert len(deck.findCards("-note:basic")) == 0
+    assert len(deck.findCards("note:basic")) == 3
+    assert len(deck.findCards("-note:basic")) == 2
     assert len(deck.findCards("-note:foo")) == 5
     # deck
     assert len(deck.findCards("deck:default")) == 5
diff --git a/pylib/tests/test_media.py b/pylib/tests/test_media.py
index 22ffba4cb..d5b7c454f 100644
--- a/pylib/tests/test_media.py
+++ b/pylib/tests/test_media.py
@@ -26,7 +26,7 @@ def test_add():
 def test_strings():
     d = getEmptyCol()
     mf = d.media.filesInStr
-    mid = list(d.models.models.keys())[0]
+    mid = d.models.current()["id"]
     assert mf(mid, "aoeu") == []
     assert mf(mid, "aoeu<img src='foo.jpg'>ao") == ["foo.jpg"]
     assert mf(mid, "aoeu<img src='foo.jpg' style='test'>ao") == ["foo.jpg"]
diff --git a/pylib/tests/test_models.py b/pylib/tests/test_models.py
index 8209a3311..7414b4cd4 100644
--- a/pylib/tests/test_models.py
+++ b/pylib/tests/test_models.py
@@ -48,6 +48,7 @@ def test_fields():
     assert d.getNote(d.models.nids(m)[0]).fields == ["1", "2", ""]
     assert d.models.scmhash(m) != h
     # rename it
+    f = m["flds"][2]
     d.models.renameField(m, f, "bar")
     assert d.getNote(d.models.nids(m)[0])["bar"] == ""
     # delete back
@@ -102,7 +103,7 @@ def test_templates():
     assert c.ord == 1
     assert c2.ord == 0
     # removing a template should delete its cards
-    assert d.models.remTemplate(m, m["tmpls"][0])
+    d.models.remTemplate(m, m["tmpls"][0])
     assert d.cardCount() == 1
     # and should have updated the other cards' ordinals
     c = f.cards()[0]
@@ -111,7 +112,11 @@ def test_templates():
     # it shouldn't be possible to orphan notes by removing templates
     t = mm.newTemplate("template name")
     mm.addTemplate(m, t)
-    assert not d.models.remTemplate(m, m["tmpls"][0])
+    d.models.remTemplate(m, m["tmpls"][0])
+    assert (
+        d.db.scalar("select count() from cards where nid not in (select id from notes)")
+        == 0
+    )
 
 
 def test_cloze_ordinals():
@@ -269,7 +274,6 @@ def test_chained_mods():
 
 def test_modelChange():
     deck = getEmptyCol()
-    basic = deck.models.byName("Basic")
     cloze = deck.models.byName("Cloze")
     # enable second template and add a note
     m = deck.models.current()
@@ -279,6 +283,7 @@ def test_modelChange():
     t["afmt"] = "{{Front}}"
     mm.addTemplate(m, t)
     mm.save(m)
+    basic = m
     f = deck.newNote()
     f["Front"] = "f"
     f["Back"] = "b123"
@@ -334,8 +339,9 @@ def test_modelChange():
     f["Front"] = "f2"
     f["Back"] = "b2"
     deck.addNote(f)
-    assert deck.models.useCount(basic) == 2
-    assert deck.models.useCount(cloze) == 0
+    counts = deck.models.all_use_counts()
+    assert next(c.use_count for c in counts if c.name == "Basic") == 2
+    assert next(c.use_count for c in counts if c.name == "Cloze") == 0
     map = {0: 0, 1: 1}
     deck.models.change(basic, [f.id], cloze, map, map)
     f.load()
@@ -362,13 +368,16 @@ def test_availOrds():
     mm.save(m, templates=True)
     assert not mm.availOrds(m, joinFields(f.fields))
     # AND
+    t = m["tmpls"][0]
     t["qfmt"] = "{{#Front}}{{#Back}}{{Front}}{{/Back}}{{/Front}}"
     mm.save(m, templates=True)
     assert not mm.availOrds(m, joinFields(f.fields))
+    t = m["tmpls"][0]
     t["qfmt"] = "{{#Front}}\n{{#Back}}\n{{Front}}\n{{/Back}}\n{{/Front}}"
     mm.save(m, templates=True)
     assert not mm.availOrds(m, joinFields(f.fields))
     # OR
+    t = m["tmpls"][0]
     t["qfmt"] = "{{Front}}\n{{Back}}"
     mm.save(m, templates=True)
     assert mm.availOrds(m, joinFields(f.fields)) == [0]
diff --git a/qt/aqt/browser.py b/qt/aqt/browser.py
index 4f899b5aa..fe850796e 100644
--- a/qt/aqt/browser.py
+++ b/qt/aqt/browser.py
@@ -1176,11 +1176,11 @@ QTableView {{ gridline-color: {grid} }}
 
     def _modelTree(self, root) -> None:
         assert self.col
-        for m in sorted(self.col.models.all(), key=itemgetter("name")):
+        for m in self.col.models.all_names_and_ids():
             item = SidebarItem(
-                m["name"],
+                m.name,
                 ":/icons/notetype.svg",
-                lambda m=m: self.setFilter("note", m["name"]),  # type: ignore
+                lambda m=m: self.setFilter("note", m.name),  # type: ignore
             )
             root.addChild(item)
 
diff --git a/qt/aqt/clayout.py b/qt/aqt/clayout.py
index 2c36ab16c..d09f0595f 100644
--- a/qt/aqt/clayout.py
+++ b/qt/aqt/clayout.py
@@ -239,21 +239,12 @@ class CardLayout(QDialog):
         if len(self.model["tmpls"]) < 2:
             return showInfo(_("At least one card type is required."))
         idx = self.ord
-        cards = self.mm.tmplUseCount(self.model, idx)
-        cards = ngettext("%d card", "%d cards", cards) % cards
         msg = _("Delete the '%(a)s' card type, and its %(b)s?") % dict(
-            a=self.model["tmpls"][idx]["name"], b=cards
+            a=self.model["tmpls"][idx]["name"], b=_("cards")
         )
         if not askUser(msg):
             return
-        if not self.mm.remTemplate(self.model, self.cards[idx].template()):
-            return showWarning(
-                _(
-                    """\
-Removing this card type would cause one or more notes to be deleted. \
-Please create a new card type first."""
-                )
-            )
+        self.mm.remTemplate(self.model, self.cards[idx].template())
         self.redraw()
 
     def removeColons(self):
diff --git a/qt/aqt/models.py b/qt/aqt/models.py
index aac73abfc..54c703f35 100644
--- a/qt/aqt/models.py
+++ b/qt/aqt/models.py
@@ -4,10 +4,12 @@ import collections
 import re
 from operator import itemgetter
 from typing import Optional
+from typing import List
 
 import aqt.clayout
 from anki import stdmodels
 from anki.lang import _, ngettext
+from anki.rsbackend import pb
 from aqt import AnkiQt, gui_hooks
 from aqt.qt import *
 from aqt.utils import (
@@ -34,6 +36,7 @@ class Models(QDialog):
         self.form = aqt.forms.models.Ui_Dialog()
         self.form.setupUi(self)
         qconnect(self.form.buttonBox.helpRequested, lambda: openHelp("notetypes"))
+        self.models: List[pb.NoteTypeNameIDUseCount] = []
         self.setupModels()
         restoreGeom(self, "models")
         self.exec_()
@@ -76,13 +79,12 @@ class Models(QDialog):
         row = self.form.modelsList.currentRow()
         if row == -1:
             row = 0
-        self.models = self.col.models.all()
-        self.models.sort(key=itemgetter("name"))
+        self.models = self.col.models.all_use_counts()
         self.form.modelsList.clear()
         for m in self.models:
-            mUse = self.mm.useCount(m)
+            mUse = m.use_count
             mUse = ngettext("%d note", "%d notes", mUse) % mUse
-            item = QListWidgetItem("%s [%s]" % (m["name"], mUse))
+            item = QListWidgetItem("%s [%s]" % (m.name, mUse))
             self.form.modelsList.addItem(item)
         self.form.modelsList.setCurrentRow(row)
 
@@ -90,7 +92,7 @@ class Models(QDialog):
         if self.model:
             self.saveModel()
         idx = self.form.modelsList.currentRow()
-        self.model = self.models[idx]
+        self.model = self.col.models.get(self.models[idx].id)
 
     def onAdd(self):
         m = AddModel(self.mw, self).get()