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Log Formatter / Viewer

Paste logs to highlight levels, pretty-print JSON lines, search, and collapse repeats. Everything runs locally in your browser.

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Levels
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Tip: JSON logs work best when each line is a JSON object.
Formatted output
Showing 10 / 10
2025-03-19T12:34:56.123Z
info
INFO Server started on port 3000
2025-03-19T12:34:57.001Z
debug
DEBUG {"event":"db.query","duration_ms":12,"sql":"SELECT 1","id":"q1"}
2025-03-19T12:34:57.050Z
debug
DEBUG {"event":"db.query","duration_ms":12,"sql":"SELECT 1","id":"q1"}
2025-03-19T12:34:57.099Z
debug
DEBUG {"event":"db.query","duration_ms":12,"sql":"SELECT 1","id":"q1"}
2025-03-19T12:34:58.410Z
warn
WARN Cache miss for key=user:123
2025-03-19T12:34:59.002Z
error
ERROR {"event":"payment.failed","reason":"insufficient_funds","user_id":123,"amount":49.99}
2025-03-19T12:35:00.000Z
trace
TRACE entering handler /api/status
info
Not JSON but has [INFO] bracketed level
info
{
  "level": "info",
  "msg": "structured log line",
  "requestId": "r-123",
  "nested": {
    "a": 1,
    "b": [
      true,
      false,
      null
    ]
  }
}
unknown