Structured Logging

Definitions

1. Logging in a machine-parseable format (JSON, logfmt) with consistent key-value fields instead of free-text strings. Enables filtering, aggregation, and correlation in log management tools (ELK, Loki, Datadog). Include request_id, user_id, duration_ms, and error details as structured fields. Unstructured logs are nearly useless at scale.

   In plain English: Logging in a structured format (like JSON) with labeled fields instead of messy text, making logs easy to search and analyze.

   Example: "{"level":"error","msg":"payment failed","user_id":"u_123","amount":99.99,"error":"card declined","request_id":"req_abc"} -- searchable, filterable, alertable."

Related Terms

• Seq
• Log Aggregation
• Log Level
• Log Parser
• Logger
• Logging Framework
• Cloud Logging
• Custom Logger