15 Free Developer Tools I Built — JSON, SQL, Regex, Cron, JWT, YAML & More

I built 15 free developer tools and deployed them all on Vercel. No signup, no ads, just tools that work.

The Tools

AI-Powered

• JSONFix — Format, validate, and AI-fix broken JSON
• SQLFormat — Format SQL + AI explains queries
• RegexAI — Describe what to match in English, get regex
• CronAI — Plain English to cron expression
• ReadMeAI — Generate README from any GitHub repo URL

Decoders & Encoders

• JWT Decoder — Decode tokens, check expiry
• Base64 — Encode/decode Base64 strings
• HashGen — SHA-256, SHA-512, Base64 hashes

Validators & Formatters

• YAMLCheck — Validate YAML, convert YAML/JSON
• DiffCheck — Compare two texts, see differences

Generators

• GitIgnore — Select stack, get .gitignore
• ColorPick — Pick colors in HEX, RGB, HSL, Tailwind

Security & Monitoring

• SiteSafe — Check any site for security headers
• PingCraft — Monitor uptime with Telegram alerts
• ReviewReply — AI responses to customer reviews

Why I Built These

I needed these tools daily and got tired of sites with popups, sign-up walls, and tracking. So I built my own.

Every tool runs in your browser (except AI features which use Claude). Your data stays on your machine.

All tools in one place: devtools-rose-kappa.vercel.app