diff --git a/lib/ops/thread-activity-store-ops.js b/lib/ops/thread-activity-store-ops.js
new file mode 100644
index 000000000..66f89fc1e
--- /dev/null
+++ b/lib/ops/thread-activity-store-ops.js
@@ -0,0 +1,133 @@
+// @flow
+
+import { type BaseStoreOpsHandlers } from './base-ops.js';
+import type {
+  ThreadActivityStore,
+  ThreadActivityStoreEntry,
+} from '../types/thread-activity-types.js';
+
+// client types
+export type ReplaceThreadActivityEntryOperation = {
+  +type: 'replace_thread_activity_entry',
+  +payload: {
+    +id: string,
+    +threadActivityStoreEntry: ThreadActivityStoreEntry,
+  },
+};
+
+export type RemoveThreadActivityEntriesOperation = {
+  +type: 'remove_thread_activity_entries',
+  +payload: { +ids: $ReadOnlyArray<string> },
+};
+
+export type RemoveAllThreadActivityEntriesOperation = {
+  +type: 'remove_all_thread_activity_entries',
+};
+
+export type ThreadActivityStoreOperation =
+  | ReplaceThreadActivityEntryOperation
+  | RemoveThreadActivityEntriesOperation
+  | RemoveAllThreadActivityEntriesOperation;
+
+// SQLite types
+export type ClientDBThreadActivityEntry = {
+  +id: string,
+  +threadActivityStoreEntry: string,
+};
+
+export type ClientDBReplaceThreadActivityEntryOperation = {
+  +type: 'replace_thread_activity_entry',
+  +payload: ClientDBThreadActivityEntry,
+};
+
+export type ClientDBThreadActivityStoreOperation =
+  | ClientDBReplaceThreadActivityEntryOperation
+  | RemoveThreadActivityEntriesOperation
+  | RemoveAllThreadActivityEntriesOperation;
+
+function convertThreadActivityEntryToClientDBThreadActivityEntry({
+  id,
+  threadActivityStoreEntry,
+}: {
+  +id: string,
+  +threadActivityStoreEntry: ThreadActivityStoreEntry,
+}): ClientDBThreadActivityEntry {
+  return {
+    id,
+    threadActivityStoreEntry: JSON.stringify(threadActivityStoreEntry),
+  };
+}
+
+const threadActivityStoreOpsHandlers: BaseStoreOpsHandlers<
+  ThreadActivityStore,
+  ThreadActivityStoreOperation,
+  ClientDBThreadActivityStoreOperation,
+  ThreadActivityStore,
+  ClientDBThreadActivityEntry,
+> = {
+  processStoreOperations(
+    threadActivityStore: ThreadActivityStore,
+    ops: $ReadOnlyArray<ThreadActivityStoreOperation>,
+  ): ThreadActivityStore {
+    if (ops.length === 0) {
+      return threadActivityStore;
+    }
+
+    let processedThreadActivityStore = threadActivityStore;
+
+    for (const operation: ThreadActivityStoreOperation of ops) {
+      if (operation.type === 'replace_thread_activity_entry') {
+        const { id, threadActivityStoreEntry } = operation.payload;
+        processedThreadActivityStore = {
+          ...processedThreadActivityStore,
+          [id]: threadActivityStoreEntry,
+        };
+      } else if (operation.type === 'remove_thread_activity_entries') {
+        for (const id of operation.payload.ids) {
+          const { [id]: _, ...rest } = processedThreadActivityStore;
+          processedThreadActivityStore = rest;
+        }
+      } else if (operation.type === 'remove_all_thread_activity_entries') {
+        processedThreadActivityStore = {};
+      }
+    }
+    return processedThreadActivityStore;
+  },
+  convertOpsToClientDBOps(
+    ops: $ReadOnlyArray<ThreadActivityStoreOperation>,
+  ): $ReadOnlyArray<ClientDBThreadActivityStoreOperation> {
+    return ops.map(threadActivityStoreOperation => {
+      if (
+        threadActivityStoreOperation.type ===
+          'remove_all_thread_activity_entries' ||
+        threadActivityStoreOperation.type === 'remove_thread_activity_entries'
+      ) {
+        return threadActivityStoreOperation;
+      }
+
+      const { id, threadActivityStoreEntry } =
+        threadActivityStoreOperation.payload;
+
+      return {
+        type: 'replace_thread_activity_entry',
+        payload: convertThreadActivityEntryToClientDBThreadActivityEntry({
+          id,
+          threadActivityStoreEntry,
+        }),
+      };
+    });
+  },
+
+  translateClientDBData(
+    data: $ReadOnlyArray<ClientDBThreadActivityEntry>,
+  ): ThreadActivityStore {
+    return Object.fromEntries(
+      data.map((dbThreadActivityEntry: ClientDBThreadActivityEntry) => [
+        dbThreadActivityEntry.id,
+        JSON.parse(dbThreadActivityEntry.threadActivityStoreEntry),
+      ]),
+    );
+  },
+};
+
+export { threadActivityStoreOpsHandlers };