---
title: worker-errors
description: Symbolicates, groups and stores errors. Port 4400 serves health only.
---

- Drains `error_intake`, the Redis queue that [api-ingest](/self-hosting/services/api-ingest) fills.
- Symbolicates browser stacks with the release's source maps. Without [object storage](/self-hosting/configuration#object-storage), stacks stay minified. Use the same bucket as `api`.
- Groups errors in PostgreSQL. A new or regressed group triggers issue alerts in `worker-jobs`.
- Writes error events and groups to ClickHouse, and syncs group status changes every minute. The sync is scheduled by `worker-jobs`.

Reads [PostgreSQL](/self-hosting/configuration#postgresql), [ClickHouse](/self-hosting/configuration#clickhouse), `REDIS_STATE_URL` from [Redis](/self-hosting/configuration#redis), the [ingest queue](/self-hosting/configuration#ingest-queue), [object storage](/self-hosting/configuration#object-storage) and [logging](/self-hosting/configuration#logging). All variables below are optional.

| Variable                   | Default     | Description                                                                                                |
| -------------------------- | ----------- | ---------------------------------------------------------------------------------------------------------- |
| `PORT`                     | `4400`      | Health port.                                                                                               |
| `SYMBOLICATION_TIMEOUT_MS` | `5000`      | Wait for a batch's source maps. Past it, stacks stay minified with an `openperf.symbolication.error` mark. |
| `SOURCE_MAP_CACHE_BYTES`   | `268435456` | Memory for parsed source maps, per instance.                                                               |
| `ERROR_GROUP_FLUSH_MS`     | `10000`     | How long group status is cached before PostgreSQL is checked for regressions. `0` checks every batch.      |
| `ERROR_INTAKE_TIMEOUT_MS`  | `120000`    | Time limit per batch. Past it, the batch is requeued and draining pauses.                                  |