Free Online Tools
Fast, free, and privacy-friendly tools that work right in your browser. No signup, no data collection.
DevToolKit is a suite of free browser-based developer tools built for programmers, DevOps engineers, and backend developers. From TOML-to-YAML conversion and SQL-to-MongoDB translation to cron expression generation and Nginx config scaffolding — every tool runs entirely in your browser with zero server uploads. Your code and configs stay private, always.
Whether you need to generate environment files, calculate chmod permissions, create HMAC hashes, or convert SVG to JSX components, our tools are designed to be fast, accurate, and completely free with no signup required.
Converters
Convert between formats and languages
JSON to Zod
Paste JSON → get a ready-to-use Zod TypeScript schema in seconds. Handles nested objects, arrays, and nullables. Perfect for Next.js and tRPC. 100% browser-based.
TOML to YAML
Paste TOML → get clean YAML output instantly. Supports nested tables, arrays, and inline values. Ideal for Cargo-to-K8s migrations. Free, no signup, runs in your browser.
YAML to TOML
Paste YAML → get valid TOML output in one click. Handles nested objects, arrays, and inline tables. Great for pyproject.toml and Cargo. Browser-based, no signup required.
SVG to JSX
Paste SVG → get a ready-to-use React JSX component with camelCase props and TypeScript types. Handles gradients, filters, and masks. 100% client-side, no data uploaded.
SQL to MongoDB
Paste a SQL query → get the MongoDB Node.js equivalent. Supports SELECT, INSERT, UPDATE, DELETE with WHERE, ORDER BY, and LIMIT. Free browser tool, no signup needed.
JSON to Protobuf
Paste JSON → get a ready-to-use Protocol Buffers (.proto) message definition instantly. Auto-detects field types, handles nested objects and arrays. Free, browser-based, no signup.
Properties to YAML
Paste Java .properties → get clean YAML output instantly. Handles nested keys (server.port → server:\n port:), comments, and special characters. Also supports YAML to Properties reverse conversion.
Generators
Generate configs, code, and boilerplate
Cron Expression Generator
Pick options → get a valid cron expression with a human-readable description. Presets for hourly, daily, weekly, and monthly. Works with GitHub Actions and K8s CronJobs.
Env File Generator
Choose a framework → get a complete .env template with documented variables. Covers Next.js, Django, Laravel, Express, and Rails. Free, editable, browser-based.
Nginx Config Generator
Fill in options → get a complete Nginx server block with SSL, gzip, and reverse proxy support. Copy-paste ready for /etc/nginx/. Free online tool, no signup required.
Docker Compose Generator
Build docker-compose.yml visually: add services, ports, volumes, env vars, and dependencies. Pre-built templates for MERN, LAMP, WordPress, Redis+Node, PostgreSQL+Django. Free, browser-based.
Formatters
Format and beautify code
SQL Formatter
Paste messy SQL → get properly indented, uppercase-keyword output instantly. Supports SELECT, JOIN, subqueries, and DDL statements. Works with MySQL, PostgreSQL, and more.
CSS Minifier
Paste CSS → get minified output with size-reduction stats. Strips comments, whitespace, and redundant semicolons. Typical savings 15-40%. Fast, private, browser-based.
HTML Prettifier
Paste minified or messy HTML → get clean, indented output in one click. Handles nested tags, void elements, and inline styles. Configurable indent size. 100% browser-based.
Utilities
Encode, decode, hash, and calculate
Chmod Calculator
Set Unix permissions with checkboxes → get numeric (755) and symbolic (rwxr-xr-x) output instantly. Includes umask mode. Works offline in your browser — no signup needed.
HMAC Generator
Enter message + secret key → get HMAC in hex and base64 instantly. Supports SHA-256, SHA-384, and SHA-512. Verify Stripe and GitHub webhook signatures. Runs 100% in-browser.