Essential Developer Tools, All in Your Browser
8 free, privacy-first tools for developers. Decode JWTs, generate UUIDs and hashes, format SQL, preview Markdown, test APIs, convert data formats, and validate cron expressions. No signup required.
JWT Decoder
Decode and verify JSON Web Tokens with detailed header and payload inspection.
UUID Generator
Generate RFC 4122 compliant UUIDs (v4) for unique identifiers in your applications.
API Request Builder
Build and test HTTP requests with custom headers, body, and authentication.
JSON/YAML/CSV Converter
Convert between JSON, YAML, and CSV formats with validation and prettification.
Cron Expression Tester
Test and validate cron expressions with next run time predictions and explanations.
Hash Generator
Generate cryptographic hashes (MD5, SHA-1, SHA-256, SHA-512) from text input.
SQL Formatter
Format and beautify SQL queries with syntax highlighting and validation.
Markdown Preview
Write Markdown with live preview and export to HTML. GitHub-flavored Markdown support.
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Privacy First
All processing happens in your browser. Your data never leaves your device.
Fast & Simple
No signup required. Just open and start using the tools instantly.
Completely Free
All tools are free to use with no limits or premium features.