NexusTools
Free developer tools that run 100% in your browser.
No uploads. No tracking. No accounts. Just tools.
toolnexus.dev
Why NexusTools?
Most "free" developer tools harvest your data, require sign-ups, or shove paywalls in your face. NexusTools is different:
- 100% client-side — Your data never leaves your browser. Zero server processing.
- No account required — Open and use. That's it.
- Fast — Lightweight tools that load instantly. No bloated SPAs.
- Open source — MIT licensed. Read the code, fork it, improve it.
- Multilingual — English, Spanish, Brazilian Portuguese, Japanese, and Korean.
Verify the privacy claim
"100% client-side" is easy to say — here's how to check it:
- Open DevTools (
F12) → Network tab.
- Use any tool: paste JSON, generate a password, decode a JWT.
- Watch the Network tab: no request carries your data. Only static assets load.
- Or read the code: every tool is a client component in
src/app/[locale]/tools/ with no fetch calls.*
*Two documented exceptions, active only when you use them: IP Geolocation queries ipapi.co, and the Favicon Generator loads fonts from Google Fonts. Details in our privacy policy.
Tools (50)
Converters & Formatters
| Tool | Description |
|---|
| JSON Formatter | Format, validate, minify, tree view, auto-repair |
| SQL Formatter | Beautify & minify SQL with syntax highlighting |
| JSON/YAML Converter | Bidirectional JSON to YAML conversion |
| JSON/CSV Converter | Convert between JSON arrays and CSV |
| CSV to SQL | Generate INSERT statements from CSV (4 SQL dialects) |
| Base64 Encoder | Encode/decode Base64 with UTF-8 support |
| URL Encoder | Encode/decode URLs (encodeURIComponent & encodeURI) |
| HTML Entity Encoder | Encode/decode HTML entities (named, decimal, hex) |
| Text Case Converter | 11 formats: camelCase, snake_case, kebab-case, and more |
| Timestamp Converter | Unix timestamps to human dates and back |
| CSS Unit Converter | Convert between px, rem, em, %, vh, vw |
| Color Converter |
Generators
| Tool | Description |
|---|
| Favicon Generator | From text, emoji, or image — ICO, PNG, SVG |
| Password Generator | Cryptographically secure with entropy meter |
| UUID Generator | v4 & v1 with bulk generation and validation |
| QR Code Generator | Custom colors, PNG & SVG export |
| Lorem Ipsum Generator | Paragraphs, sentences, or words |
| Placeholder Image | Custom dimensions, colors, text overlay |
| Hash Generator | MD5, SHA-1, SHA-256, SHA-512 + HMAC |
| Meta Tag Generator | SEO, Open Graph, Twitter Cards |
| Color Palette Generator | 6 harmony types from any base color |
| JWT Generator | Sign HS256/384/512 tokens with Web Crypto |
| .gitignore Generator | Templates for languages, frameworks, and editors |
CSS Visual Tools
Developer Utilities
| Tool | Description |
|---|
| Regex Tester | Live highlighting, capture groups, cheat sheet |
| JWT Decoder | Decode tokens, inspect claims, check expiration |
| Diff Checker | Side-by-side text comparison with stats |
| Chmod Calculator | Interactive Unix permissions grid |
| Cron Expression Builder | Visual builder with next execution preview |
| Markdown Preview | GFM with tables, code blocks, live preview |
| Aspect Ratio Calculator | GCD ratio, resolution table, CSS output |
| LLM Token Counter | Estimate tokens for GPT, Claude, Llama, Gemini |
| Character Counter | Chars, words, sentences, bytes, reading time |
| HTTP Status Codes | Searchable reference for 1xx–5xx |
| CIDR Calculator | Subnet mask, IP range, binary breakdown |
| IP Geolocation |
Image Tools
Tech Stack
- Framework: Next.js 15 (App Router, TypeScript)
- Styling: Tailwind CSS v4
- i18n: next-intl (EN, ES, PT-BR, JA, KO)
- Processing: 100% client-side (Canvas API, Web Crypto, native JS)
- Dependencies: Near zero — most tools use only browser APIs
Run Locally
git clone https://github.com/nexustools-dev/nexus-tools.git
cd nexus-tools
npm install
npm run dev
Open localhost:3000.
Contributing
We welcome contributions! Here's how:
- Suggest a tool — Open an Idea discussion
- Report a bug — Open an Issue
- Submit code — Fork, create a branch, open a PR
Adding a new tool
Each tool follows this pattern:
src/app/[locale]/tools/your-tool/
page.tsx ← Server component (SEO metadata)
YourTool.tsx ← Client component ("use client")
src/messages/{en,es,pt,ja,ko}/your-tool.json ← i18n translations
Tools must be:
- 100% client-side (no backend calls)
- Translated to all 5 languages
- Include SEO content below the tool
License
MIT — Use it, fork it, build on it.
toolnexus.dev — Built with care for the developer community.
