100 free browser-based developer tools. No npm, no build step, no signup, no tracking.
Every tool is a standalone HTML file. View source — it's all there. Works offline after first load.
| Tool | What it does |
|---|---|
| JSON Format | Beautify, validate, minify, tree view |
| JSON Diff | Compare two JSON objects |
| Regex Test | Live matching, capture groups, 12 presets |
| Diff Text | Side-by-side line + word diff |
| Cron Explain | Plain English + next 10 run times |
| Base64 | Encode/decode text and files |
| Hash Gen | MD5, SHA-1, SHA-256, SHA-512 |
| JWT Builder | Create & decode JWTs |
| URL Parser | Break URLs into components |
| UUID Gen | v4/v7, ULID, nanoid, bulk generate |
| Timestamp | Unix ↔ human time, timezone convert |
| HTML Escape | Encode/decode HTML entities |
| Lorem Gen | Lorem ipsum paragraphs, sentences, words |
| Password Gen | Configurable secure passwords |
| CSV ↔ JSON | Bidirectional with table preview |
| YAML ↔ JSON | Docker Compose sample included |
| TOML ↔ JSON | Cargo.toml, pyproject.toml presets |
| SQL Format | Beautify + minify SQL queries |
| Markdown Table | Visual editor → formatted markdown |
| JSON → TypeScript | Generate TS interfaces from JSON |
| Encode Decode | URL, Base64, HTML, Hex, Binary, ROT13 |
| Number Base | Binary, hex, octal, decimal converter |
| Data URI | Convert files to data URIs and back |
| Case Convert | camelCase, snake_case, PascalCase, etc. |
| Subnet Calc | IP subnet calculator, CIDR notation |
| JSON Schema | Generate JSON Schema from samples |
| Keycode | JavaScript keyboard event keycode finder |
| Git Cheatsheet | 57 Git commands with examples and danger levels |
| Regex Cheatsheet | 67 regex patterns with examples |
| HTML to JSX | Convert HTML to valid JSX/React syntax |
| Tailwind Converter | CSS ↔ Tailwind bidirectional converter |
| HTML Minifier | Minify & beautify HTML with statistics |
| JS Minifier | Minify & beautify JavaScript with statistics |
| CSS Minifier | Minify & beautify CSS with statistics |
| JSON Viewer | Interactive JSON tree viewer with search |
| API Tester | Browser-based REST API client |
| Regex Replace | Find & replace with regex, live preview |
| JSON Path | Query JSON with JSONPath expressions |
| Tool | What it does |
|---|---|
| Color Palette | 6 harmony schemes, WCAG contrast |
| Color Convert | HEX ↔ RGB ↔ HSL ↔ HSB ↔ CMYK |
| Font Pair | 20 Google Font pairings |
| Font Preview | Browse 1500+ Google Fonts |
| CSS Shadow | Box-shadow generator |
| CSS Gradient | Linear/radial gradient builder |
| CSS Flex | Flexbox playground |
| CSS Grid | Grid layout generator |
| CSS Animation | Keyframe animator, 12 presets |
| CSS Filter | blur, contrast, sepia, etc. |
| Border Radius | 8-point control, 10 presets |
| Box Model | Interactive margin/padding visualizer |
| Spacing Calc | Design system scale generator |
| CSS Units | px ↔ rem ↔ em ↔ vw ↔ vh |
| Aspect Ratio | Calculate and convert ratios |
| SVG Preview | Paste SVG, see it live |
| Favicon Gen | Generate favicons from text/emoji |
| Text Transform | camelCase, snake_case, UPPER, etc. |
| Image Resize | Resize in browser, keep ratio |
| Emoji Picker | Search and copy emoji |
| Color Extract | Extract palette from images |
| Contrast Check | WCAG color contrast checker |
| CSS Clip-Path | Visual clip-path generator |
| Placeholder Image | Custom placeholder image generator |
| Color Blind Sim | Simulate 8 types of color blindness |
| CSS Text Shadow | text-shadow generator, multi-layer |
| CSS Glass | Glassmorphism generator |
| CSS Neumorphism | Soft UI shadow generator |
| HSL Picker | HSL color picker with harmonies |
| CSS Cursor | Preview all CSS cursor types |
| CSS Transform | Visual transform generator with presets |
| CSS Transition | Transition generator with cubic-bezier editor |
| CSS Variables | Custom properties generator with theme builder |
| CSS Media Query | Visual media query builder with device presets |
| CSS Specificity | Specificity calculator with compare and quiz |
| Color Mixer | Mix colors with RGB/HSL/CIELAB modes |
| CSS Reset | Browse, compare, customize 8 CSS resets |
| Tool | What it does |
|---|---|
| chmod Calc | Permission calculator |
| HTTP Status | All status codes explained |
| DNS Lookup | A, AAAA, MX, NS, TXT records |
| SSL Check | Certificate expiry checker |
| Headers Check | HTTP response headers |
| IP Info | Your IP, geolocation, ISP |
| Meta Tags | OG/Twitter meta tag generator |
| QR Code | Generate QR codes |
| Tool | What it does |
|---|---|
| Word Count | Words, chars, reading time |
| Title Score | Blog title analyzer |
| README Score | README quality checker |
| GitHub Stats | Repo analytics dashboard |
| npm Health | Package health score |
| npm Compare | Side-by-side package comparison |
| GitHub Card | Shareable profile card generator |
| Repo Compare | Side-by-side repo comparison |
| Dep Tree | npm dependency tree visualizer |
| LLM Price | Compare AI model pricing |
| Prompt Price | Calculate prompt costs |
| Model Picker | Choose the right AI model |
| AI ROI Calc | AI investment calculator |
| Dev.to Stats | Article analytics |
| Markdown Preview | Live markdown renderer |
| OG Preview | Social media link preview checker |
| Char Count | Character counter with platform limits |
- Single HTML file — view source, it's all there
- Runs in your browser — nothing leaves your machine
- No dependencies — works offline after first load
- Dark theme — because it's 2026
MIT