diff --git a/src/browser/js/bridge.zig b/src/browser/js/bridge.zig
index 9559d9a94..29cb0cc57 100644
--- a/src/browser/js/bridge.zig
+++ b/src/browser/js/bridge.zig
@@ -1000,6 +1000,7 @@ pub const PageJsApis = flattenTypes(&.{
     @import("../webapi/XPathResult.zig"),
     @import("../webapi/XPathExpression.zig"),
     @import("../webapi/XPathEvaluator.zig"),
+    @import("../webapi/collections/DOMStringList.zig"),
 });
 
 // APIs available on Worker context globals (constructors like URL, Headers, etc.)
@@ -1061,6 +1062,8 @@ pub const WorkerJsApis = flattenTypes(&.{
     @import("../webapi/storage/idb/idb.zig"),
     @import("../webapi/event/CookieChangeEvent.zig"),
     @import("../webapi/BroadcastChannel.zig"),
+    @import("../webapi/BroadcastChannel.zig"),
+    @import("../webapi/collections/DOMStringList.zig"),
 });
 
 // Master list of ALL JS APIs across all contexts.
diff --git a/src/browser/webapi/collections.zig b/src/browser/webapi/collections.zig
index eeb884929..4a1fefba3 100644
--- a/src/browser/webapi/collections.zig
+++ b/src/browser/webapi/collections.zig
@@ -43,9 +43,5 @@ pub fn registerTypes() []const type {
         DOMTokenList.KeyIterator,
         DOMTokenList.ValueIterator,
         DOMTokenList.EntryIterator,
-        DOMStringList,
-        DOMStringList.KeyIterator,
-        DOMStringList.ValueIterator,
-        DOMStringList.EntryIterator,
     };
 }
diff --git a/src/browser/webapi/collections/DOMStringList.zig b/src/browser/webapi/collections/DOMStringList.zig
index 99531e6e2..24e4ea1e1 100644
--- a/src/browser/webapi/collections/DOMStringList.zig
+++ b/src/browser/webapi/collections/DOMStringList.zig
@@ -21,7 +21,6 @@ const lp = @import("lightpanda");
 
 const js = @import("../../js/js.zig");
 const Page = @import("../../Page.zig");
-const Frame = @import("../../Frame.zig");
 const GenericIterator = @import("iterator.zig").Entry;
 
 pub const KeyIterator = GenericIterator(Iterator, "0");
@@ -31,6 +30,17 @@ pub const EntryIterator = GenericIterator(Iterator, null);
 const Execution = js.Execution;
 const Allocator = std.mem.Allocator;
 
+// not registered in collections.zig, because this is one of the rare
+// collections that's also available in Worker
+pub fn registerTypes() []const type {
+    return &.{
+        DOMStringList,
+        DOMStringList.KeyIterator,
+        DOMStringList.ValueIterator,
+        DOMStringList.EntryIterator,
+    };
+}
+
 pub const DOMStringList = @This();
 
 _rc: lp.RC(u8) = .{},
diff --git a/src/browser/webapi/storage/idb/Engine.zig b/src/browser/webapi/storage/idb/Engine.zig
index 6d80c9621..7b5c0b36e 100644
--- a/src/browser/webapi/storage/idb/Engine.zig
+++ b/src/browser/webapi/storage/idb/Engine.zig
@@ -172,6 +172,10 @@ pub fn close(self: *Engine) void {
     self.conn.close();
 }
 
+pub fn lastError(self: *const Engine) [:0]const u8 {
+    return self.conn.lastError();
+}
+
 pub fn begin(self: *Engine) !void {
     return self.conn.exec("begin immediate", .{});
 }
diff --git a/src/browser/webapi/storage/idb/IDBCursor.zig b/src/browser/webapi/storage/idb/IDBCursor.zig
index ac93b47f4..391ffc0d9 100644
--- a/src/browser/webapi/storage/idb/IDBCursor.zig
+++ b/src/browser/webapi/storage/idb/IDBCursor.zig
@@ -60,6 +60,9 @@ _key: ?[]const u8 = null,
 _primary_key: ?[]const u8 = null,
 // Current record's serialized value bytes (null when key-only or exhausted).
 _value: ?[]const u8 = null,
+// The deserialized JS value, cached so repeated `.value` reads return the same
+// object (and observe mutations to it). Reset whenever the cursor repositions.
+_value_js: ?*js.Value.BareGlobal = null,
 
 // Backing storage for _key/_primary_key/_value, reused across positions so a
 // long scan holds one record's worth of memory, not the whole traversal.
@@ -160,7 +163,7 @@ pub fn releaseRef(self: *IDBCursor, page: *Page) void {
 // Run the deferred seek, staging the positioned cursor (or null) on the request.
 pub fn runIterate(self: *IDBCursor, seek: Seek, offset: u32, exec: *Execution) !void {
     self.iterate(seek, offset, exec) catch |err| {
-        log.warn(.storage, "idb cursor iterate", .{ .err = err });
+        log.warn(.storage, "idb cursor iterate", .{ .err = err, .sqlite = self._engine.lastError() });
         self._request.setError(err);
     };
 }
@@ -222,21 +225,17 @@ pub fn advance(self: *IDBCursor, count: u32, exec: *Execution) !void {
 }
 
 pub fn update(self: *IDBCursor, value: js.Value, exec: *Execution) !*IDBRequest {
-    if (self._txn._mode == .readonly) {
-        return error.ReadOnlyError;
-    }
-
-    if (self._txn._settled == true) {
-        return error.TransactionInactiveError;
-    }
-
-    if (self._got_value == false) {
-        return error.InvalidStateError;
-    }
+    try self.assertCanUpdate();
 
     // The record sits at the primary (store) key, even for an index cursor.
     const current_key = self._primary_key orelse return error.InvalidStateError;
 
+    // Structured-clone the value now, synchronously: an unserializable value must
+    // throw DataCloneError from update() itself, not fail later in the drain. The
+    // stored clone also decouples the record from any later mutation of the arg.
+    const serialized = value.serialize() catch return error.TryCatchRethrow;
+    defer serialized.deinit();
+
     // For an in-line store, the value's own key must match the record's key.
     if (self._store._key_path) |kp| {
         const extracted = Key.evaluatePath(value, kp) orelse return error.DataError;
@@ -246,28 +245,24 @@ pub fn update(self: *IDBCursor, value: js.Value, exec: *Execution) !*IDBRequest
         }
     }
 
-    // Snapshot the record key: the write runs in the drain, by which point a
-    // `continue` could have moved the cursor's live position (and reused its
-    // key buffer).
+    // Snapshot the record key and the serialized clone onto the transaction arena:
+    // the write runs in the drain, by which point a `continue` could have moved
+    // the cursor's live position (and reused its key buffer).
     const key = try self._txn._arena.dupe(u8, current_key);
+    const bytes = try self._txn._arena.dupe(u8, serialized.bytes());
     const request = try self._txn.newRequest();
-    const value_global = try self._txn.persist(value);
-    return request.submit(.{ .cursor_update = .{ .cursor = self, .key = key, .value = value_global } }, exec);
+    return request.submit(.{ .cursor_update = .{ .cursor = self, .key = key, .value = bytes } }, exec);
 }
 
-pub fn runUpdate(self: *IDBCursor, request: *IDBRequest, key: []const u8, value_global: *js.Value.BareGlobal, exec: *Execution) !void {
-    defer value_global.deinit();
+pub fn runUpdate(self: *IDBCursor, request: *IDBRequest, key: []const u8, bytes: []const u8, exec: *Execution) !void {
     const local = exec.js.local.?;
-    const value = value_global.local(local);
-
-    const serialized = value.serialize() catch |err| {
+    const value = js.Value.deserialize(local, bytes) catch |err| {
         request.setError(err);
         return;
     };
-    defer serialized.deinit();
 
-    self._store.writeAt(key, value, serialized.bytes(), exec) catch |err| {
-        log.warn(.storage, "idb cursor update", .{ .err = err });
+    self._store.writeAt(key, value, bytes, exec) catch |err| {
+        log.warn(.storage, "idb cursor update", .{ .err = err, .sqlite = self._engine.lastError() });
         request.setError(err);
         return;
     };
@@ -275,17 +270,7 @@ pub fn runUpdate(self: *IDBCursor, request: *IDBRequest, key: []const u8, value_
 }
 
 pub fn delete(self: *IDBCursor, exec: *Execution) !*IDBRequest {
-    if (self._txn._mode == .readonly) {
-        return error.ReadOnlyError;
-    }
-
-    if (self._txn._settled == true) {
-        return error.TransactionInactiveError;
-    }
-
-    if (self._got_value == false) {
-        return error.InvalidStateError;
-    }
+    try self.assertCanUpdate();
 
     // Snapshot the record key (see update): the delete runs later, in the drain.
     const current_key = self._primary_key orelse return error.InvalidStateError;
@@ -296,7 +281,7 @@ pub fn delete(self: *IDBCursor, exec: *Execution) !*IDBRequest {
 
 pub fn runDelete(self: *IDBCursor, request: *IDBRequest, key: []const u8) !void {
     self._store.deleteAt(key) catch |err| {
-        log.warn(.storage, "idb cursor delete", .{ .err = err });
+        log.warn(.storage, "idb cursor delete", .{ .err = err, .sqlite = self._engine.lastError() });
         request.setError(err);
     };
 }
@@ -359,6 +344,7 @@ fn reiterate(self: *IDBCursor, seek: Seek, offset: u32, exec: *Execution) !void
 
 fn position(self: *IDBCursor, key: []const u8, primary_key: []const u8, value: ?[]const u8) !void {
     const arena = self._txn._arena;
+    self.invalidateValue();
 
     self._key_buf.clearRetainingCapacity();
     try self._key_buf.appendSlice(arena, key);
@@ -379,12 +365,36 @@ fn position(self: *IDBCursor, key: []const u8, primary_key: []const u8, value: ?
 }
 
 fn exhaust(self: *IDBCursor) void {
+    self.invalidateValue();
     self._key = null;
     self._primary_key = null;
     self._value = null;
     self._request.setNull();
 }
 
+// Drop any cached `.value` object; the next read re-deserializes at the new
+// position. The persisted slot's handle is reset here so it doesn't pin the old
+// value until transaction teardown.
+fn invalidateValue(self: *IDBCursor) void {
+    if (self._value_js) |slot| {
+        slot.deinit();
+        self._value_js = null;
+    }
+}
+
+// The deserialized current value, created on first read and cached so repeated
+// `.value` accesses return the same JS object (see IDBCursorWithValue.getValue).
+pub fn getValueJs(self: *IDBCursor, exec: *Execution) !?js.Value {
+    const bytes = self._value orelse return null;
+    const local = exec.js.local.?;
+    if (self._value_js) |slot| {
+        return slot.local(local);
+    }
+    const value = try js.Value.deserialize(local, bytes);
+    self._value_js = try self._txn.persist(value);
+    return value;
+}
+
 // validate the state before we can advance/continue
 fn prepareIterate(self: *IDBCursor) !void {
     if (self._txn._settled == true) {
@@ -398,6 +408,20 @@ fn prepareIterate(self: *IDBCursor) !void {
     self._got_value = false;
 }
 
+fn assertCanUpdate(self: *IDBCursor) !void {
+    try self._txn.assertActive();
+
+    if (self._txn._mode == .readonly) {
+        return error.ReadOnlyError;
+    }
+    if (self._store._deleted) {
+        return error.InvalidStateError;
+    }
+    if (self._got_value == false) {
+        return error.InvalidStateError;
+    }
+}
+
 pub const JsApi = struct {
     pub const bridge = js.Bridge(IDBCursor);
 
diff --git a/src/browser/webapi/storage/idb/IDBCursorWithValue.zig b/src/browser/webapi/storage/idb/IDBCursorWithValue.zig
index a3ef220fd..aee1bf1cc 100644
--- a/src/browser/webapi/storage/idb/IDBCursorWithValue.zig
+++ b/src/browser/webapi/storage/idb/IDBCursorWithValue.zig
@@ -33,8 +33,7 @@ pub fn init(cursor: *IDBCursor) !*IDBCursorWithValue {
 }
 
 pub fn getValue(self: *const IDBCursorWithValue, exec: *Execution) !?js.Value {
-    const bytes = self._proto._value orelse return null;
-    return try js.Value.deserialize(exec.js.local.?, bytes);
+    return self._proto.getValueJs(exec);
 }
 
 pub const JsApi = struct {
diff --git a/src/browser/webapi/storage/idb/IDBFactory.zig b/src/browser/webapi/storage/idb/IDBFactory.zig
index 36abc8d73..d0d503890 100644
--- a/src/browser/webapi/storage/idb/IDBFactory.zig
+++ b/src/browser/webapi/storage/idb/IDBFactory.zig
@@ -131,7 +131,7 @@ const OpenContext = struct {
         }
 
         const upgrading = self.runOpen(engine) catch |err| blk: {
-            log.warn(.storage, "idb open", .{ .err = err, .name = self.name });
+            log.warn(.storage, "idb open", .{ .err = err, .name = self.name, .sqlite = engine.lastError() });
             self.request.setError(err);
             self.request.deliver(self.exec) catch {};
             break :blk false;
@@ -350,7 +350,7 @@ const DeleteContext = struct {
         defer _ = engine.releaseGate(&self._gate_waiter);
 
         self.runDelete(engine) catch |err| {
-            log.warn(.storage, "idb deleteDatabase", .{ .err = err, .name = self.name });
+            log.warn(.storage, "idb deleteDatabase", .{ .err = err, .name = self.name, .sqlite = engine.lastError() });
             self.request.setError(err);
             self.request.deliver(self.exec) catch {};
         };
diff --git a/src/browser/webapi/storage/idb/IDBIndex.zig b/src/browser/webapi/storage/idb/IDBIndex.zig
index 03c532342..be83891b1 100644
--- a/src/browser/webapi/storage/idb/IDBIndex.zig
+++ b/src/browser/webapi/storage/idb/IDBIndex.zig
@@ -82,7 +82,7 @@ pub fn get(self: *IDBIndex, query: js.Value, exec: *Execution) !*IDBRequest {
 pub fn runGet(self: *IDBIndex, request: *IDBRequest, bounds: Engine.Bounds, exec: *Execution) !void {
     const arena = exec.call_arena;
     const bytes = self._engine.indexGetRange(arena, self._store._store_id, self._index_id, bounds) catch |err| {
-        log.warn(.storage, "idb index get", .{ .err = err });
+        log.warn(.storage, "idb index get", .{ .err = err, .sqlite = self._engine.lastError() });
         request.setError(err);
         return;
     };
@@ -100,7 +100,7 @@ pub fn getKey(self: *IDBIndex, query: js.Value, exec: *Execution) !*IDBRequest {
 pub fn runGetKey(self: *IDBIndex, request: *IDBRequest, bounds: Engine.Bounds, exec: *Execution) !void {
     const arena = exec.call_arena;
     const bytes = self._engine.indexGetKeyRange(arena, self._index_id, bounds) catch |err| {
-        log.warn(.storage, "idb index getKey", .{ .err = err });
+        log.warn(.storage, "idb index getKey", .{ .err = err, .sqlite = self._engine.lastError() });
         request.setError(err);
         return;
     };
@@ -132,7 +132,7 @@ fn _getAll(self: *IDBIndex, query_or_options: ?js.Value, count_: ?u32, mode: IDB
 
 pub fn runGetAll(self: *IDBIndex, request: *IDBRequest, args: IDBKeyRange.GetAllArgs, mode: IDBObjectStore.GetAllMode, exec: *Execution) !void {
     const arr = self.collectAll(args, mode, exec) catch |err| {
-        log.warn(.storage, "idb index getAll", .{ .err = err });
+        log.warn(.storage, "idb index getAll", .{ .err = err, .sqlite = self._engine.lastError() });
         request.setError(err);
         return;
     };
@@ -176,7 +176,7 @@ pub fn count(self: *IDBIndex, query: ?js.Value, exec: *Execution) !*IDBRequest {
 
 pub fn runCount(self: *IDBIndex, request: *IDBRequest, bounds: Engine.Bounds, exec: *Execution) !void {
     const n = self._engine.indexCountRange(self._index_id, bounds) catch |err| {
-        log.warn(.storage, "idb index count", .{ .err = err });
+        log.warn(.storage, "idb index count", .{ .err = err, .sqlite = self._engine.lastError() });
         request.setError(err);
         return;
     };
diff --git a/src/browser/webapi/storage/idb/IDBObjectStore.zig b/src/browser/webapi/storage/idb/IDBObjectStore.zig
index e934243be..1451c2178 100644
--- a/src/browser/webapi/storage/idb/IDBObjectStore.zig
+++ b/src/browser/webapi/storage/idb/IDBObjectStore.zig
@@ -44,6 +44,7 @@ _name: []const u8,
 _key_path: ?[]const u8,
 _auto_increment: bool,
 _txn: *IDBTransaction,
+_deleted: bool = false,
 // identity map, store.indexes('a') === store.index('a')
 _indexes: std.ArrayList(*IDBIndex) = .empty,
 
@@ -83,6 +84,7 @@ pub fn put(self: *IDBObjectStore, value: js.Value, key: ?js.Value, exec: *Execut
 }
 
 pub fn get(self: *IDBObjectStore, query: js.Value, exec: *Execution) !*IDBRequest {
+    try self.assertLive();
     const txn = self._txn;
     try txn.assertActive();
     const bounds = try IDBKeyRange.resolveQuery(txn._arena, query, exec);
@@ -93,7 +95,7 @@ pub fn get(self: *IDBObjectStore, query: js.Value, exec: *Execution) !*IDBReques
 pub fn runGet(self: *IDBObjectStore, request: *IDBRequest, bounds: Engine.Bounds, exec: *Execution) !void {
     const arena = exec.call_arena;
     const bytes = self._engine.getRange(arena, self._store_id, bounds) catch |err| {
-        log.warn(.storage, "idb get", .{ .err = err });
+        log.warn(.storage, "idb get", .{ .err = err, .sqlite = self._engine.lastError() });
         request.setError(err);
         return;
     };
@@ -102,6 +104,7 @@ pub fn runGet(self: *IDBObjectStore, request: *IDBRequest, bounds: Engine.Bounds
 }
 
 pub fn delete(self: *IDBObjectStore, query: js.Value, exec: *Execution) !*IDBRequest {
+    try self.assertLive();
     const txn = self._txn;
     if (txn._mode == .readonly) {
         return error.ReadOnlyError;
@@ -114,7 +117,7 @@ pub fn delete(self: *IDBObjectStore, query: js.Value, exec: *Execution) !*IDBReq
 
 pub fn runDelete(self: *IDBObjectStore, request: *IDBRequest, bounds: Engine.Bounds, _: *Execution) !void {
     self.deleteBounds(bounds) catch |err| {
-        log.warn(.storage, "idb delete", .{ .err = err });
+        log.warn(.storage, "idb delete", .{ .err = err, .sqlite = self._engine.lastError() });
         request.setError(err);
     };
 }
@@ -125,6 +128,7 @@ fn deleteBounds(self: *IDBObjectStore, bounds: Engine.Bounds) !void {
 }
 
 pub fn clear(self: *IDBObjectStore, exec: *Execution) !*IDBRequest {
+    try self.assertLive();
     const txn = self._txn;
     if (txn._mode == .readonly) {
         return error.ReadOnlyError;
@@ -136,7 +140,7 @@ pub fn clear(self: *IDBObjectStore, exec: *Execution) !*IDBRequest {
 
 pub fn runClear(self: *IDBObjectStore, request: *IDBRequest, _: *Execution) !void {
     self.clearAll() catch |err| {
-        log.warn(.storage, "idb clear", .{ .err = err });
+        log.warn(.storage, "idb clear", .{ .err = err, .sqlite = self._engine.lastError() });
         request.setError(err);
     };
 }
@@ -147,6 +151,7 @@ fn clearAll(self: *IDBObjectStore) !void {
 }
 
 pub fn count(self: *IDBObjectStore, query: ?js.Value, exec: *Execution) !*IDBRequest {
+    try self.assertLive();
     const txn = self._txn;
     try txn.assertActive();
     const bounds = try IDBKeyRange.resolveQuery(txn._arena, query, exec);
@@ -156,7 +161,7 @@ pub fn count(self: *IDBObjectStore, query: ?js.Value, exec: *Execution) !*IDBReq
 
 pub fn runCount(self: *IDBObjectStore, request: *IDBRequest, bounds: Engine.Bounds, exec: *Execution) !void {
     const n = self._engine.countRange(self._store_id, bounds) catch |err| {
-        log.warn(.storage, "idb count", .{ .err = err });
+        log.warn(.storage, "idb count", .{ .err = err, .sqlite = self._engine.lastError() });
         request.setError(err);
         return;
     };
@@ -175,6 +180,7 @@ pub fn getAllKeys(self: *IDBObjectStore, query_or_options: ?js.Value, count_: ?u
 }
 
 pub fn getAllRecords(self: *IDBObjectStore, options: ?js.Value, exec: *Execution) !*IDBRequest {
+    try self.assertLive();
     const txn = self._txn;
     try txn.assertActive();
     const args = try IDBKeyRange.resolveGetAllOptions(txn._arena, options, exec);
@@ -183,6 +189,7 @@ pub fn getAllRecords(self: *IDBObjectStore, options: ?js.Value, exec: *Execution
 }
 
 fn _getAll(self: *IDBObjectStore, query_or_options: ?js.Value, count_: ?u32, mode: GetAllMode, exec: *Execution) !*IDBRequest {
+    try self.assertLive();
     const txn = self._txn;
     try txn.assertActive();
     const args = try IDBKeyRange.resolveGetAll(txn._arena, query_or_options, count_, exec);
@@ -192,7 +199,7 @@ fn _getAll(self: *IDBObjectStore, query_or_options: ?js.Value, count_: ?u32, mod
 
 pub fn runGetAll(self: *IDBObjectStore, request: *IDBRequest, args: IDBKeyRange.GetAllArgs, mode: GetAllMode, exec: *Execution) !void {
     const arr = self.collectAll(exec, args, mode) catch |err| {
-        log.warn(.storage, "idb getAll", .{ .err = err });
+        log.warn(.storage, "idb getAll", .{ .err = err, .sqlite = self._engine.lastError() });
         request.setError(err);
         return;
     };
@@ -225,6 +232,7 @@ fn collectAll(self: *IDBObjectStore, exec: *Execution, args: IDBKeyRange.GetAllA
 }
 
 pub fn getKey(self: *IDBObjectStore, query: js.Value, exec: *Execution) !*IDBRequest {
+    try self.assertLive();
     const txn = self._txn;
     try txn.assertActive();
     const bounds = try IDBKeyRange.resolveQuery(txn._arena, query, exec);
@@ -235,7 +243,7 @@ pub fn getKey(self: *IDBObjectStore, query: js.Value, exec: *Execution) !*IDBReq
 pub fn runGetKey(self: *IDBObjectStore, request: *IDBRequest, bounds: Engine.Bounds, exec: *Execution) !void {
     const arena = exec.call_arena;
     const found = self._engine.getKeyRange(arena, self._store_id, bounds) catch |err| {
-        log.warn(.storage, "idb getKey", .{ .err = err });
+        log.warn(.storage, "idb getKey", .{ .err = err, .sqlite = self._engine.lastError() });
         request.setError(err);
         return;
     };
@@ -244,11 +252,13 @@ pub fn runGetKey(self: *IDBObjectStore, request: *IDBRequest, bounds: Engine.Bou
 }
 
 pub fn openCursor(self: *IDBObjectStore, query: ?js.Value, direction: ?IDBCursor.Direction, exec: *Execution) !*IDBRequest {
+    try self.assertLive();
     const bounds = try IDBKeyRange.resolveQuery(self._txn._arena, query, exec);
     return IDBCursor.init(self, bounds, direction orelse .next, false, exec);
 }
 
 pub fn openKeyCursor(self: *IDBObjectStore, query: ?js.Value, direction: ?IDBCursor.Direction, exec: *Execution) !*IDBRequest {
+    try self.assertLive();
     const bounds = try IDBKeyRange.resolveQuery(self._txn._arena, query, exec);
     return IDBCursor.init(self, bounds, direction orelse .next, true, exec);
 }
@@ -285,6 +295,7 @@ pub const PreparedKey = union(enum) {
 };
 
 fn write(self: *IDBObjectStore, value: js.Value, key_arg: ?js.Value, kind: WriteKind, exec: *Execution) !*IDBRequest {
+    try self.assertLive();
     const txn = self._txn;
     if (txn._mode == .readonly) {
         return error.ReadOnlyError;
@@ -345,7 +356,7 @@ pub fn runWrite(self: *IDBObjectStore, request: *IDBRequest, kind: WriteKind, va
     defer value_global.deinit();
     self.writeInner(request, kind, value_global, prepared, exec) catch |err| {
         if (err != error.Constraint) {
-            log.warn(.storage, "idb write", .{ .err = err, .kind = kind });
+            log.warn(.storage, "idb write", .{ .err = err, .kind = kind, .sqlite = self._engine.lastError() });
         }
         request.setError(err);
     };
@@ -463,10 +474,13 @@ const CreateIndexOptions = struct {
 
 // Only callable during an upgrade (versionchange transaction).
 pub fn createIndex(self: *IDBObjectStore, name: []const u8, key_path: []const u8, options: ?CreateIndexOptions, exec: *Execution) !*IDBIndex {
+    try self.assertLive();
     const txn = self._txn;
     if (txn._mode != .versionchange) {
         return error.InvalidStateError;
     }
+    // Spec order: the transaction-state check precedes the index-name check.
+    try txn.assertActive();
     const opts = options orelse CreateIndexOptions{};
 
     try self._engine.savepoint();
@@ -508,10 +522,13 @@ pub fn createIndex(self: *IDBObjectStore, name: []const u8, key_path: []const u8
 
 // Only callable during an upgrade (versionchange transaction).
 pub fn deleteIndex(self: *IDBObjectStore, name: []const u8, _: *Execution) !void {
+    try self.assertLive();
     const txn = self._txn;
     if (txn._mode != .versionchange) {
         return error.InvalidStateError;
     }
+    // Spec order: the transaction-state check precedes the index-name check.
+    try txn.assertActive();
     self._engine.deleteIndexRow(self._store_id, name) catch |err| switch (err) {
         error.NotFound => return error.NotFoundError,
         else => return err,
@@ -525,6 +542,7 @@ pub fn deleteIndex(self: *IDBObjectStore, name: []const u8, _: *Execution) !void
 }
 
 pub fn index(self: *IDBObjectStore, name: []const u8, _: *Execution) !*IDBIndex {
+    try self.assertLive();
     for (self._indexes.items) |idx| {
         if (std.mem.eql(u8, idx._name, name)) {
             return idx;
@@ -549,6 +567,12 @@ pub fn getIndexNames(self: *IDBObjectStore, exec: *Execution) !*DOMStringList {
     return list;
 }
 
+fn assertLive(self: *const IDBObjectStore) !void {
+    if (self._deleted) {
+        return error.InvalidStateError;
+    }
+}
+
 pub const JsApi = struct {
     pub const bridge = js.Bridge(IDBObjectStore);
 
diff --git a/src/browser/webapi/storage/idb/IDBRequest.zig b/src/browser/webapi/storage/idb/IDBRequest.zig
index 2a95d2555..e6e7ae5ca 100644
--- a/src/browser/webapi/storage/idb/IDBRequest.zig
+++ b/src/browser/webapi/storage/idb/IDBRequest.zig
@@ -361,7 +361,7 @@ pub const Operation = union(enum) {
     const IndexQuery = struct { index: *IDBIndex, bounds: Engine.Bounds };
     const IndexGetAll = struct { index: *IDBIndex, args: IDBKeyRange.GetAllArgs, mode: IDBObjectStore.GetAllMode };
     const CursorIterate = struct { cursor: *IDBCursor, seek: IDBCursor.Seek, offset: u32 };
-    const CursorUpdate = struct { cursor: *IDBCursor, key: []const u8, value: *js.Value.BareGlobal };
+    const CursorUpdate = struct { cursor: *IDBCursor, key: []const u8, value: []const u8 };
     const CursorDelete = struct { cursor: *IDBCursor, key: []const u8 };
 };
 
diff --git a/src/browser/webapi/storage/idb/IDBTransaction.zig b/src/browser/webapi/storage/idb/IDBTransaction.zig
index 16b2da278..aa65f7515 100644
--- a/src/browser/webapi/storage/idb/IDBTransaction.zig
+++ b/src/browser/webapi/storage/idb/IDBTransaction.zig
@@ -307,7 +307,7 @@ pub fn settleStep(self: *IDBTransaction, exec: *Execution) bool {
 fn commitAndComplete(self: *IDBTransaction, exec: *Execution) void {
     if (self._begun) {
         self._engine.commit() catch |err| {
-            log.warn(.storage, "idb commit", .{ .err = err, .sqlite = self._engine.conn.lastError() });
+            log.warn(.storage, "idb commit", .{ .err = err, .sqlite = self._engine.lastError() });
             self._engine.rollback();
             self._begun = false;
             _ = self._engine.releaseGate(&self._gate_waiter);
@@ -385,6 +385,7 @@ pub fn cacheStore(self: *IDBTransaction, store: *IDBObjectStore) !void {
 pub fn uncacheStore(self: *IDBTransaction, name: []const u8) void {
     for (self._stores.items, 0..) |store, i| {
         if (std.mem.eql(u8, store._name, name)) {
+            store._deleted = true;
             _ = self._stores.swapRemove(i);
             return;
         }