Logs

JSON Log Line (Single-Line Object)

Match a single-line JSON object — typical of structured logging from services like slog, Bunyan, or Pino.

Try it in RegexPro →

Available in

JSSupported

JavaScript / ECMAScript

Browser-native RegExp. Default if you don't pick.

PYSupported

Python (re)

CPython stdlib `re`. Unicode-aware `\w` and `\d` by default.

GOSupported

Go (RE2)

Linear-time matching. No backreferences or lookarounds.

Pattern

regexengine-agnostic
^\{(?:[^{}]|\{[^{}]*\})*\}$

Raw source: ^\{(?:[^{}]|\{[^{}]*\})*\}$

How it works

^\{ anchors to an opening brace at start. (?:[^{}]|\{[^{}]*\})* matches any non-brace chars or one level of nested braces (so `{"a":{"b":1}}` matches but deeper nesting may not). \}$ anchors to the closing brace at end. Quick filter for log-line shape; pair with JSON.parse to validate fully.

Examples

Input

{"level":"info","msg":"started","port":8080}

Matches

  • {"level":"info","msg":"started","port":8080}

Input

{"event":"login","user":{"id":42}}

Matches

  • {"event":"login","user":{"id":42}}

Input

plain text log line

No match

—

Common use cases

  • •Splitting mixed-format log streams (text vs JSON)
  • •Routing JSON lines to a parser, text to a different sink
  • •Pre-filter for log shippers (Vector, Fluentd, Filebeat)
  • •Log-line shape validation in observability pipelines
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