Watchers

Watchers are what Lens captures. Each one records a type of signal — requests, database queries, cache operations, exceptions, mail, jobs, and more — and correlates it to the request that produced it. Enable the ones you need; ignore the rest.

Most watchers live in your framework adapter and are toggled from your lens() config. The ORM, cache, and mailer integrations ship in the watchers package:

$npm install @lensjs/watchers

Available watchers

Requests

Incoming HTTP requests with headers, body, response, status, duration, and user.

Database Queries

Prisma, Kysely, Sequelize, MikroORM, Drizzle, Mongoose, and Lucid.

Cache

Hits, misses, writes, and evictions across your caching layer.

Exceptions

Automatic capture with stack traces and fingerprint grouping.

Mail

Outgoing email with MIME previews, iCalendar, and attachments.

HTTP Client

Outbound fetch calls, with W3C trace propagation.

Events

Application events emitted during a request.

Redis

Redis commands issued by your app.

FCM (Push)

Firebase Cloud Messaging push notifications.

Logs

Console, pino, and winston log lines.

Jobs & Queues

BullMQ and Agenda jobs as they run.

How enabling works

Request and exception watchers are on by default. The rest are opt-in via flags like cacheWatcherEnabled, mailWatcherEnabled, or a queryWatcher handler — see each watcher's page and the Configuration reference.