Small tools, clear boundaries
Useful file tools that work in your browser
Clean, convert and check common data without creating an account or uploading the contents.
Choose a tool
Clean a CSV onlineTrim cell whitespace and remove exact duplicate rows without uploading your file.Convert CSV to JSONConvert CSV rows to JSON objects locally while preserving every cell as text.Convert JSON to CSVConvert a flat JSON array to CSV locally with safe spreadsheet exports.Check JSON against a schemaValidate JSON against a safe, bounded JSON Schema subset without uploading either document.Convert SRT to WebVTTConvert strict SRT subtitles to WebVTT locally and flag overlapping cues.
Private by design
The five tools in this release run as deterministic JavaScript on your device. Useful Commons does not receive the text or files you process.