Fast browser tools for developers
working with data, APIs, and debugging.
Inspect JSON, decode tokens, parse URLs, convert formats.
Everything runs locally in your browser — no data leaves your machine.
Data Inspection & Formatting
Format, validate, diff, and flatten JSON and structured data.
JSON Formatter
Format, validate, and beautify JSON data with syntax highlighting
JSON Minifier
Minify and compress JSON data by removing all unnecessary whitespace
JSON Diff
Compare two JSON objects and see added, removed, and changed values highlighted
JSON Schema Validator
Validate JSON data against a JSON Schema to check structure and types
JSON Flatten/Unflatten
Flatten nested JSON to dot-notation keys or unflatten back to nested structure
JSON to TypeScript
Convert JSON data to TypeScript interfaces or type aliases instantly
Auth & Encoding
Decode JWTs, encode Base64, and escape strings safely.
JWT Decoder
Decode and inspect JSON Web Tokens instantly
JWT Generator
Generate and sign JSON Web Tokens (JWT) for testing with HS256, HS384, HS512
Base64 Encoder
Encode and decode Base64 strings instantly
URL Encoder/Decoder
Encode and decode URLs with percent-encoding
HTML Encoder/Decoder
Encode and decode HTML entities to prevent XSS and display HTML safely
Unicode Escape/Unescape
Escape text to \uXXXX Unicode sequences or unescape them back to readable text
Request Debugging
Parse URLs, inspect headers, and convert cURL to fetch.
Patterns & Scheduling
Test regex patterns, parse cron expressions, and convert timestamps.
Why developers use ToolHarbor
Runs locally
All processing happens in your browser. Your data never leaves your machine.
No sign-up
No accounts, no login walls, no tracking. Open a tool and start working.
Fast & focused
Lightweight tools built for developer workflows — not bloated with ads or upsells.
Open source
The full source code is public on GitHub. Inspect it, contribute, or fork it.