Why write logs as structured events (JSON fields such as user_id, trace_id, duration_ms) rather than free-text lines?

Answer

Fields can be filtered and aggregated directly ("errors for this customer in the last hour, by endpoint") instead of parsed with fragile regular expressions that break when a message is reworded. A trace_id field links each line to its trace.

Why

Structure does not make logs cheap: log volume grows with traffic, so keep debug logs off or sampled in production, and never log secrets, tokens or passwords; redact them in the logging library.

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