JSONloggar

JSONloggar refer to log entries emitted in JSON format rather than plain text. They are a core component of structured logging, where each log event is a self-describing JSON object. This approach is common in modern software systems, particularly those deployed at scale or in cloud-native environments, because it enables machine parsing and automatic aggregation.

A typical JSON log includes mandatory fields such as timestamp, level, and message, plus optional metadata such as logger or service name, host, environment, and identifiers used for tracing (trace_id, span_id, request_id). Logs may be written as one JSON object per line (JSON Lines) to simplify streaming and indexing.

Benefits include improved searchability, easier integration with log-management platforms (Elasticsearch, Logstash, Kibana; Loki; Cloud Logging), and consistent structure across services. It also supports richer context and better correlation across distributed systems. Drawbacks include increased storage size, potential schema drift, and the need to sanitize sensitive information before ingestion.

Common implementations span Serilog, Bunyan, Pino, and Logrus, among others. Web services often adopt schemas and conventions for fields, timestamps in ISO 8601 UTC, and stable keys to enable efficient querying. For best results, teams establish a naming convention, use structured data rather than free-form messages, and pair JSON logs with robust access controls and data governance.