558 browser-based developer tools · All offline · Zero dependencies · One HTML file each
Dev Vault is a collection of 558 standalone HTML tools covering CSS, JavaScript, security, networking, design, data, DevOps, and more.
Every tool is a single HTML file — open it in a browser and it just works. No build step, no npm install, no signup, no tracking.
- 🌐 Open the portal — open
index.htmlto browse all tools by category - 📁 Browse files —
tools/<category>/<name>.html - 🧪 Run tests —
node tests/run.mjs(smoke + functional probe for every tool,node tests/run_specs.mjsfor the deep specs intests/specs/)
| Category | Count | Examples |
|---|---|---|
| JavaScript | 132 | Web APIs, patterns, visualizers, engine internals |
| Code | 109 | JSON, regex, JWT, hash, cron, docker, git |
| CSS | 63 | Layout, animation, painting, responsive, container queries |
| Design | 52 | Color, typography, SVG, icon, image, CSS generators |
| Math | 36 | Evaluator, benchmark, geo distance, unit converter |
| Data | 26 | npm, GitHub, pypi, crate, SSL, license |
| Converter | 20 | JSON↔TOML↔YAML↔XML, temperature, IBAN, date |
| Text | 18 | Case convert, slugify, NATO, binary, Unicode |
| Security | 17 | CSP, CORS, JWT, SRI, cookie inspector |
| Image | 11 | Crop, filter, watermark, Base64, sprite sheet |
| Crypto | 11 | Hash, HMAC, RSA, Bcrypt, BIP39, OTP |
| Network | 10 | DNS, IPv4/6, HTTP, TLS, WebSocket, MAC |
| Writing | 9 | Markdown, word count, reading time, title score |
| Net | 7 | DNS tools, header inspection, TCP/IP helpers |
| DevOps | 6 | Docker, K8s, Terraform, Grafana |
| Media | 5 | Audio/Video players, media API playgrounds |
| AI | 5 | LLM pricing, prompt cost, model picker |
| 4 | Merge, split, compress, convert | |
| Perf | 4 | Page speed, bundle analysis, performance APIs |
| Reference | 3 | Cheatsheets, API references |
| API | 2 | API testers and inspectors |
| SEO | 2 | Meta inspector, sitemap tools |
| Color | 2 | Color conversion and palettes |
| Infra | 1 | Infrastructure helpers |
| Device | 1 | Device info |
| OCR | 1 | Image text extraction |
| Chart | 1 | Chart generators |
# Clone
git clone https://github.com/gokuscraper/dev-vault.git
# Open the portal (or open any tool file directly)
open index.html
# Run tests (requires Node.js + Playwright)
npm install
node tests/run.mjs- Single HTML file — view source, inspect, learn
- Fully offline — after first load, everything is local
- Zero telemetry — no analytics, no tracking, no ads
- Dark theme — defaults to dark mode
Some content is sourced from yurukusa/dev-toolkit. Design references CorentinTh/it-tools.
MIT License · Built with ❤️