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Free Online Developer Tools
12 toolsRuns in your browser
Format, encode, decode, hash and test, with nothing sent to a server. Safe to use on real tokens and payloads.
Developer Tools
- JSON Formatter & ValidatorFormat, minify and validate JSON with clear error positions.
- JSON to CSV ConverterTurn a JSON array of objects into CSV for Excel or Google Sheets.
- Base64 Encode & DecodeEncode text to Base64 or decode Base64 back to text (UTF-8 safe).
- URL Encode & DecodePercent-encode or decode URLs and query-string values.
- JWT DecoderDecode a JSON Web Token locally and check its expiry.
- SHA-256 Hash GeneratorHash text or a file with SHA-256, SHA-1, SHA-384 or SHA-512.
- Binary, Decimal & Hex ConverterConvert numbers between binary, octal, decimal and hex; text to binary.
- Regex TesterTest JavaScript regular expressions with live match highlighting.
- Cron Expression GeneratorBuild a cron expression, read it in plain English and preview next runs.
- Unix Timestamp ConverterConvert Unix/epoch timestamps to dates and dates to timestamps.
Generators & Random
Developer utilities that stay local
Pasting a token, API response or config file into an online tool is a real risk when the tool uploads what you paste. Every tool here runs entirely in your browser with no network requests of its own, so you can inspect a JWT, validate JSON or hash a string without the data leaving your machine. Even so, treat live production secrets with care and prefer test data when you can.
The tools are deliberately small: no frameworks, no dependencies, quick to load. Each page explains the format involved (for example what Base64 is and is not, or what the five cron fields mean) so the output is easier to trust.