Every developer needs a solid toolkit. Here are 10 free tools you can use right now — no signup, no downloads, no BS.
1. JSON Formatter & Validator
Paste messy JSON, get it formatted and validated instantly. Catches syntax errors with line numbers.
Try it: JSON Formatter
2. Base64 Encoder/Decoder
Encode strings, decode tokens, handle file-to-base64 conversions. Essential for API debugging.
Try it: Base64 Tool
3. JWT Decoder
Decode JWT tokens without sending them to a third party. See header, payload, and verify signatures locally.
Try it: JWT Decoder
4. Regex Tester
Write and test regex patterns with real-time matching, capture groups, and common pattern library.
Try it: Regex Tester
5. Cron Expression Builder
Build cron expressions visually. See next 10 execution times. Never guess cron syntax again.
Try it: Cron Builder
6. SQL Formatter
Format messy SQL queries with proper indentation. Supports SELECT, INSERT, UPDATE, CREATE TABLE.
Try it: SQL Formatter
7. Color Picker & Converter
Convert between HEX, RGB, HSL. Generate palettes. Check contrast ratios for accessibility.
Try it: Color Picker
8. API Tester
Test REST APIs right in your browser. Set headers, body, auth. See response times and formatted output.
Try it: API Tester
9. Subnet Calculator
Calculate CIDR ranges, network addresses, broadcast addresses, usable hosts. Essential for DevOps.
Try it: Subnet Calculator
10. UUID Generator
Generate v4 UUIDs in bulk. Copy individually or all at once. Simple and fast.
Try it: UUID Generator
All tools run client-side — your data never leaves your browser. No accounts, no tracking, no limits.
Full toolkit (265+ tools): DevTools Site
What tools do you use daily? Drop them in the comments.
Top comments (0)