Debug sensitive data
safely.
Stop pasting your API keys, JWT tokens, and customer data into online formatters. OfflineTools provides a secure, offline environment for all your debugging needs.
Format & Validate
JSON, CSV, and XML tools that handle large files instantly.
API Testing
Test endpoints like Postman, but lighter and faster.
Regex & Logic
Test complex patterns and logic without server roundtrips.
All Developer Utilities
API Tester
Test APIs with a Postman-like interface.
CSV Editor
Edit CSV files with a spreadsheet-like interface.
JSON Editor
View, edit and format JSON with validation.
LLM Token Compression
Minify JSON by removing spaces and formatting to reduce prompt token usage.
Credit Card BIN Checker
Check BIN/IIN prefixes to detect likely card network and BIN traits.
Regex Lab
Test regex against sample text with explainers.
Diff Checker
Side-by-side text and code diff checker.
JWT Inspector
Decode and verify JWT structure offline.
Schema Data Generator
Generate bulk mock data (JSON/CSV) based on your custom schema locally.
Why local dev tools matter
Every developer has done it: pasted a JSON blob with PII or a production JWT into an online decoder. While convenient, this exposes your data to third-party logs and analytics.
OfflineTools Developer Toolkit is designed to replace those risky online utilities. Whether you are formatting a 50MB JSON file or testing a regex pattern, everything happens in your browser's memory.
- Zero Latency: No network requests means instant feedback.
- Security Compliance: Safe to use with production data (since it never leaves your machine).
- Works Offline: Perfect for coding on a plane or with spotty wifi.