Structured logging.

also: structured logs · JSON logs · log levels

Writing logs as key-value records (JSON) with consistent fields such as trace_id and user_id, so they can be searched and aggregated.

the two-minute refresher

'payment failed for 123' is hard to query; {event: payment_failed, user_id: 123, trace_id: …} is easy.
Use levels deliberately: ERROR needs attention, WARN is unusual, INFO is business events, DEBUG is off in production.
Never log secrets or personal data.

also: structured logs · JSON logs · log levels

Writing logs as key-value records (JSON) with consistent fields such as trace_id and user_id, so they can be searched and aggregated.

'payment failed for 123' is hard to query; {event: payment_failed, user_id: 123, trace_id: …} is easy.
Use levels deliberately: ERROR needs attention, WARN is unusual, INFO is business events, DEBUG is off in production.
Never log secrets or personal data.