Logfmt ↔ JSON Converter
Convert logfmt key=value log lines to JSON and back. Bulk processing with file upload. Runs in your browser — no upload to server.
How to use
- 1
Paste or upload logfmt lines
Enter one logfmt record per line, or upload a .log or .txt file.
- 2
Choose direction
Toggle between Logfmt → JSON and JSON → Logfmt.
- 3
Download the result
Copy the output or download it as a .jsonl file.
Why use this tool?
- Converts logfmt key=value lines to structured JSON objects
- Reverse: encode JSON objects back to logfmt format
- Bulk processing — handles thousands of lines instantly
- Runs entirely in your browser — log data never leaves your device
Frequently asked questions
- What is logfmt?
- Logfmt is a logging format popularised by Heroku and widely used in Go services. Each log line is a series of key=value pairs, making logs both human-readable and machine-parseable.
- Are the values typed?
- Logfmt is stringly typed — all values are strings. Bare words without = are treated as boolean true flags. Use JSON if you need typed values.
- Is my log data sent anywhere?
- No. All parsing and encoding happens in your browser using JavaScript. Nothing is uploaded.
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