csvjson is a free, browser-based toolkit for converting data between the formats developers and analysts use daily: JSON, CSV, Excel, YAML, XML, SQL, and more. Every conversion runs entirely in your browser. Nothing is uploaded to a server. Nothing is logged. No account required, no file size limits. Converters include: JSON ↔ CSV, Excel, YAML, XML, SQL, TSV CSV ↔ JSON, Excel, SQL Excel ↔ JSON, CSV XML ↔ JSON, YAML ↔ JSON, NDJSON → JSON Developer tools include: JSON Formatter, Validator, Schema Validator JSON Path Finder, Flatten JSON JWT Decoder, Regex Tester, Diff Checker SQL Formatter, Cron Builder Base64, URL Encode/Decode, Hash Generator (SHA-256/512) UUID Generator, Timestamp Converter CSV Viewer/Editor, CSV Cleaner QR Code Generator, Markdown Preview Developers use it to transform API responses, generate SQL seed data, decode JWTs, and validate schemas. Analysts use it to clean and reformat exports before loading into Excel or Sheets. Non-technical users use it to open a JSON file or convert a CSV without writing any code. Most online converters upload your data to their servers. csvjson processes everything locally using JavaScript — your data never leaves your device. This matters for anyone handling production data, customer records, or anything governed by data privacy policies