All Developer Tools
189+ free utilities across 14 categories — all running entirely in your browser. Format code, convert data, generate UUIDs, encode Base64, test regex, decode JWTs, build CSS, create diagrams and more. No account required, nothing uploaded to any server.
JSON FormatterSQL FormatterUUID GeneratorJWT DecoderRegex TesterBase64AES EncryptionCSS GeneratorDiff ViewerQR Code+ 179 more
Browse by Category
14 categories · 189 tools33 tools
Formatters
Format and beautify code: JSON, SQL, HTML, CSS, JS, XML
Explore 33 tools
64 tools
Converters
Convert between JSON, CSV, XML, YAML, SQL and more
Explore 64 tools
15 tools
Security
Hash, encrypt, sign and decode — SHA256, Bcrypt, JWT, RSA
Explore 15 tools
8 tools
Encoders & Decoders
Encode and decode Base64, URL, HTML entities, Binary, Hex, Gzip and Punycode
Explore 8 tools
12 tools
UI Tools
CSS generators for Flexbox, Grid, gradients, shadows, buttons plus colour tools and SVG generators
Explore 12 tools
7 tools
Diagrams
Visualise architecture with Flowcharts, PlantUML, Mermaid, JSON graph and UML class diagrams
Explore 7 tools
11 tools
Text & String
Word counter, case converter, slug generator, Lorem Ipsum, string utilities and more
Explore 11 tools
5 tools
Numbers & Dates
Calculators for units, dates, numbers, timestamps, Roman numerals and base conversions
Explore 5 tools
6 tools
Image & Media
Photo editor, image converter, QR code, code screenshots, video thumbnail and screenshot beautifier
Explore 6 tools
6 tools
Web & SEO
SEO tools, keyword density, HTTP tester, CORS generator, security headers and more
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12 tools
Developer Tools
Regex tester, diff viewer, JSONPath tester, HTML entities reference and more
Explore 12 tools
3 tools
DevOps & Network
Cron expression builder, chmod calculator and hex/IP converter
Explore 3 tools
6 tools
Form Generators
Generate HTML, React, Next.js, Angular, Bootstrap and Tailwind forms visually
Explore 6 tools
1 tools
Validators
Validate JSON, YAML, XML, JavaScript and CSS syntax with detailed error reporting
Explore 1 tools
Instant results
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Nothing uploaded
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Zero signup required
Works offline
Browser-based WASM
About Developer Tools
A single platform with 189+ free browser-based developer tools across 14 categories. Every tool runs entirely client-side — your data never leaves your browser. No account required, no file uploads, no rate limits. Open a tool, paste your data, get your result instantly.
Features
- ✓Formatters & Minifiers — format or minify JSON, SQL, HTML, CSS, JavaScript, TypeScript, XML, YAML, CSV, Java, Python, Go, PHP, C#, GraphQL, TOML, Markdown and more
- ✓Converters — convert between JSON, YAML, TOML, XML, CSV, SQL, HTML, Markdown, Base64, URL encoding and 30+ other formats
- ✓Code Generators — generate TypeScript interfaces, Python dataclasses, Go structs, Rust enums, Kotlin data classes, C# records, Java POJO, Swift Codable, Zod schemas, GraphQL types, Prisma models and more from JSON
- ✓Security Tools — password generator, bcrypt/Argon2 hasher, JWT decoder, AES-256/ChaCha20 encryption, HMAC/SHA/MD5 hash generator, SSH/RSA key pair generator, CORS header generator, security headers checker
- ✓CSS & UI Tools — CSS generators (shadows, glassmorphism, gradient text), button designer, clip-path editor, colour palette, SVG generators, SVG Icon Studio (160k+ icons) and HTML/CSS/JS playgrounds
- ✓Diagram Tools — Mermaid editor (flowcharts, sequence, ER, class, Gantt), PlantUML renderer, JSON graph and OpenAPI class explorer
- ✓Encoders — Base64 encoder/decoder, URL encoder/decoder, HTML entity encoder, binary/hex converters, Gzip compress/decompress and Punycode/IDN converter
- ✓Validators — JSON, YAML, XML, JavaScript and CSS syntax validation with detailed line-number error reporting
- ✓Developer Utilities — regex tester, diff viewer, JSONPath tester, HTML entities reference, HTTP request tester, UUID generator and more
- ✓Text & Number Tools — string case converters, word/character counter, Lorem Ipsum generator, number base converter, Roman numeral converter, unit converter
Common Use Cases
- Format and validate a JSON API response, then generate TypeScript interfaces — all without leaving the browser
- Convert a TOML configuration file to YAML or JSON for use in a different deployment pipeline
- Generate a strong random password, hash it with bcrypt and verify the hash — all in seconds
- Design a CSS button, check its colour contrast for WCAG compliance, then copy the ready-to-paste CSS
- Test an HTTP API endpoint, inspect the response headers and validate the JSON response body in one workflow
- Decode a JWT token from an Authorization header to inspect its claims and expiry time
- Compare two versions of a config file or JSON document side-by-side with visual diff highlighting
- Draw a system architecture or sequence diagram with Mermaid and export it as an SVG or PNG
Frequently Asked Questions
QAre all tools completely free?
Yes — all 189+ tools are free, with no account, no subscription, no trial period and no hidden paywalls. They are funded by the open-source community and will remain free.
QDoes my data get uploaded to a server?
No. Every tool processes data entirely in your browser using JavaScript and WebAssembly. Nothing you paste, type or import is transmitted to any server. Your data stays private.
QDo the tools work offline?
Most tools work offline once the page has loaded, because all processing is done client-side. Some tools that rely on external data (like icon libraries) may require a connection for the initial asset download.
QWhat categories are available?
There are 14 categories: Formatters, Converters, Generators, Security, CSS & UI, Diagrams, Encoders, Validators, Developer Utilities, Text Tools and more. Each category has its own listing page with a search bar.
QCan I browse tools by programming language or technology?
Yes — the Browse by Technology page (/tools/tech) lets you filter all tools by the language or data format they work with, such as JSON, YAML, SQL, JavaScript, TypeScript, Python, GraphQL, SVG, TOML, HTTP and more.
QHow often are new tools added?
New tools are added regularly. The platform is open source and welcomes community contributions. If you need a specific tool that is not yet available, you can open an issue or submit a pull request.
See Also
- JSON FormatterFormat, validate and beautify JSON documents
- SQL FormatterFormat and minify SQL queries
- UUID GeneratorGenerate v1, v4 and v5 UUIDs instantly
- Password GeneratorGenerate strong, cryptographically random passwords
- JWT DecoderDecode and inspect JWT tokens without a secret
- Base64 EncoderEncode and decode Base64 strings
- Regex TesterTest regular expressions with live match highlighting
- Diff ViewerSide-by-side visual diff for text and code