Application logs

Open an application and select Logs to view its live standard output and error output. Logs are the fastest way to understand startup, request handling, background work, and application errors.

Read the viewer

The connection badge can show:

• Connecting — the dashboard is opening the stream;
• Live — new output can arrive;
• Stream ended — the current stream ended normally;
• Disconnected — the viewer lost access to the stream.

Error output is visually distinguished from normal output. The event count shows how many entries are currently buffered in the viewer.

Reconnect

Select Reconnect when the stream is disconnected or when an active deployment began after you opened the page. If reconnection fails, confirm that the application has an active deployment and refresh application state.

Download logs

Select Download to save the entries currently loaded in the browser. The download is a snapshot, not a guarantee of complete historical retention.

Write useful application logs

Good logs describe an event without exposing protected data. Include a timestamp through your application’s logging system, severity, component, safe request or job identifier, and actionable message.

Prefer:

ERROR billing-worker payment lookup failed request_id=req_42 timeout=true

Avoid:

ERROR login failed password=hunter2 access_token=...

Never log passwords, access tokens, session cookies, private keys, full payment details, MFA codes, or secret environment values.

No logs appear

Check whether the deployment is live, whether the app writes to standard output or error, and whether the process is still running. Reconnect once. Then inspect the newest deployment output for an earlier build or startup failure.