Logging

Nhost Functions support logging through standard console methods in Node.js. Use console.log(), console.warn(), and console.error() to log messages during function execution. All logs are captured and displayed in the logs page page with metadata about each invocation.

Log Format

Each log entry includes:

Field	Description
`log`	The actual log message
`path`	The function path that generated the log
`invocationId`	Unique identifier for this function invocation
`level`	Log level: `INFO`, `WARN`, or `ERROR`

Example log entry:

{
  "log": "This was logged with console.log",
  "path": "/function",
  "invocationId": "cb1835df-a5e6-440b-ab59-e2e2f563c176",
  "level": "INFO"
}

Execution Metrics

Each function execution also generates a metrics log entry with performance data:

{
  "path": "/function",
  "invocationId": "cb1835df-a5e6-440b-ab59-e2e2f563c176",
  "status": "success",
  "metrics": {
    "durationMs": 11.067,
    "producedBytes": 718
  },
  "spans": [
    { "name": "responseLatency", "durationMs": 9.913, "start": "2026-01-10T11:38:03.850Z" },
    { "name": "responseDuration", "durationMs": 0.057, "start": "2026-01-10T11:38:03.860Z" },
    { "name": "runtimeOverhead", "durationMs": 1.023, "start": "2026-01-10T11:38:03.860Z" }
  ]
}

Correlating Logs

Invocation ID

The invocationId is unique to each function invocation and helps correlate all logs from the same execution. Access it in your code via:

req.invocationId

Request ID

You can pass a custom x-request-id header from the client for tracing requests across services:

req.headers['x-request-id']

If not provided, a unique request ID is generated automatically.