How do I disable logs from `powersync_db.worker.js` in production?

[nicholaschiang]

In my production web build, I see a ton of undesirable logs from the PowerSync worker in the browser console:

[PowerSync] FINE: 2026-06-25 01:00:59.043: [in] SyncWorkerMessageType.okResponse [powersync_db.worker.js:6097:78](http://localhost:3000/powersync_db.worker.js)
[PowerSync] INFO: 2026-06-25 01:00:59.044: Sync setup: Connecting to endpoint [powersync_db.worker.js:6097:78](http://localhost:3000/powersync_db.worker.js)
[PowerSync] INFO: 2026-06-25 01:00:59.045: Sync setup: Has database, starting sync! [powersync_db.worker.js:6097:78](http://localhost:3000/powersync_db.worker.js)
[PowerSync] INFO: 2026-06-25 01:00:59.341: Starting Rust sync iteration [powersync_db.worker.js:6097:78](http://localhost:3000/powersync_db.worker.js)
[PowerSync] FINE: 2026-06-25 01:00:59.350: Broadcasting sync event: SyncStatus<connected: connecting downloading: false (progress: null) uploading: false lastSyncedAt: 2026-06-25 00:58:21.000 hasSynced: null error: null> [powersync_db.worker.js:6097:78](http://localhost:3000/powersync_db.worker.js)
[PowerSync] FINE: 2026-06-25 01:00:59.355: [in] SyncWorkerMessageType.okResponse [powersync_db.worker.js:6097:78](http://localhost:3000/powersync_db.worker.js)
[PowerSync] FINE: 2026-06-25 01:00:59.470: Broadcasting sync event: SyncStatus<connected: true downloading: false (progress: null) uploading: false lastSyncedAt: 2026-06-25 00:58:21.000 hasSynced: null error: null> [powersync_db.worker.js:6097:78](http://localhost:3000/powersync_db.worker.js)
[PowerSync] FINE: 2026-06-25 01:00:59.477: Broadcasting sync event: SyncStatus<connected: true downloading: true (progress: for total: 0 / 0) uploading: false lastSyncedAt: 2026-06-25 00:58:21.000 hasSynced: null error: null> [powersync_db.worker.js:6097:78](http://localhost:3000/powersync_db.worker.js)
[PowerSync] FINE: 2026-06-25 01:00:59.501: Validated and applied checkpoint [powersync_db.worker.js:6097:78](http://localhost:3000/powersync_db.worker.js)
[PowerSync] FINE: 2026-06-25 01:00:59.502: Broadcasting sync event: SyncStatus<connected: true downloading: false (progress: null) uploading: false lastSyncedAt: 2026-06-25 01:00:59.000 hasSynced: null error: null> [powersync_db.worker.js:6097:78](http://localhost:3000/powersync_db.worker.js)

...how do I silence these for my production build?

[simolus3]

PowerSync uses package:logging to emit logs, you can use that package to configure how logs are managed.

If you don't pass a custom logger to PowerSyncDatabase constructors, PowerSync will:

• For debug builds, create it's own independent logger to print everything with level FINE and above.
• For release builds, use Logger('PowerSync') without attaching a log listener to it.

In your case, I assume there's another system using package:logging and listens for records? A reliable way to get PowerSync to shut up would be to use

// Note that this will stop Logger('x') from receiving log messages from Logger('y'). If you listen to logs in your app
// on a non-root logger, check that this is what you want
hierarchicalLoggingEnabled = true;

Logger('PowerSync').level = .INFO;

Alternatively, you can also pass an independent Logger.detached() to PowerSyncDatabase but then you're responsible for listening on that since its logs would not show up in Logger.root.onRecord

[nicholaschiang]

I pass in a custom logger that is silenced in production:

final _log = Logger('PowerSync');

@Riverpod(keepAlive: true)
Future<PowerSyncDatabase> powerSyncInstance(Ref ref) async {
  final db = PowerSyncDatabase(
    schema: schema,
    path: await _getDatabasePath(),
    logger: _log,
  );
  await db.initialize();
...
}

Future<void> main() async {
  if (kDebugMode) {
    Logger.root.level = Level.FINE;
    Logger.root.onRecord.listen((record) {
      debugPrint(
        '[${record.loggerName}] ${record.level.name}: ${record.time}: ${record.message}',
      );

      if (record.error != null) {
        debugPrint(record.error.toString());
      }
      if (record.stackTrace != null) {
        debugPrint(record.stackTrace.toString());
      }
    });
  } else {
    Logger.root.level = Level.OFF;
  }
...
}

I suspect that is unrelated to this issue, where I'm seeing web browser console logs from the powersync_db.worker.js script. That script appears to be a minified JS script. I downloaded that script using:

dart run powersync:setup_web

[simolus3]

The sync worker itself does emit logs to its console, but logs from shared workers usually aren't visible in the console for your tab (or at least they're not visible for me unless I pass a logger to the PowerSync database where we explicitly forward them).

Are you seeing this in Chrome? I can double check with a release build to make sure.

[nicholaschiang]

I see these logs for my production build in the browser console in both Chrome and Firefox. I can probably make a repro with the examples in this repository if that'd be helpful.

[simolus3]

Yes, I think that would be helpful. For comparison, this is is what I see in demos/supabase-todolist after replacing the logger setup in main() with Logger.root.level = Level.OFF:

This happens both in debug and release builds.