diff --git a/ts/reviewer/BUILD.bazel b/ts/reviewer/BUILD.bazel
index ebc3b79f0..d93e70534 100644
--- a/ts/reviewer/BUILD.bazel
+++ b/ts/reviewer/BUILD.bazel
@@ -14,10 +14,13 @@ compile_sass(
     deps = [],
 )
 
-
 ts_library(
     name = "reviewer_ts",
-    srcs = glob(["*.ts"]),
+    srcs = glob(
+        ["*.ts"],
+        exclude = ["reviewer_extras.ts"],
+    ),
+    module_name = "reviewer",
     deps = [
         "//ts/lib",
         "//ts/lib:backend_proto",
@@ -42,6 +45,25 @@ esbuild(
     ],
 )
 
+esbuild(
+    name = "reviewer_extras",
+    srcs = [
+        "reviewer_extras.ts",
+    ],
+    args = [
+        "--resolve-extensions=.mjs,.js",
+        "--log-level=warning",
+    ],
+    entry_point = "reviewer_extras.ts",
+    visibility = ["//visibility:public"],
+    deps = [
+        ":reviewer_ts",
+        "//ts/lib",
+        "//ts/lib:backend_proto",
+        "@npm//protobufjs",
+    ],
+)
+
 # Tests
 ################
 
diff --git a/ts/reviewer/reviewer_extras.ts b/ts/reviewer/reviewer_extras.ts
new file mode 100644
index 000000000..6b5212eb5
--- /dev/null
+++ b/ts/reviewer/reviewer_extras.ts
@@ -0,0 +1,9 @@
+// Copyright: Ankitects Pty Ltd and contributors
+// License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
+
+// A standalone bundle that adds mutateNextCardStates to the anki namespace.
+// When all clients are using reviewer.js directly, we can get rid of this.
+
+import { mutateNextCardStates } from "reviewer/answering";
+
+globalThis.anki.mutateNextCardStates = mutateNextCardStates;