Developer Tools

Essential tools for developers. API testing, code generation, JSON schema, Git commands, and development utilities.

26 free tools available

Free API Tester Online

Test REST APIs with GET, POST, PUT, DELETE requests. Free, fast, and works entirely in your browser with no sign-up required.

Free cURL to Code Converter

Convert cURL commands to code in JavaScript, Python, PHP. Free, fast, and works entirely in your browser with no sign-up required.

Free JSON Schema Generator

Generate JSON Schema from your JSON data automatically. Free, fast, and works entirely in your browser with no sign-up required.

Free HTTP Headers Parser

Parse and analyze HTTP headers from requests and responses. Free, fast, and works entirely in your browser with no sign-up required.

Free Git Command Generator

Generate common Git commands with a visual interface. Free, fast, and works entirely in your browser with no sign-up required.

Free .gitignore Generator

Generate .gitignore files for any programming language or framework. Free, fast, and works entirely in your browser with no sign-up required.

Free NPM Package Lookup

Look up NPM package information, versions, and dependencies. Free, fast, and works entirely in your browser with no sign-up required.

Free Code Snippet Manager

Save, organize, and manage your reusable code snippets locally in the browser. Free, fast, and works entirely in your browser with no sign-up required.

Free SQL to MongoDB Converter

Convert SQL queries to MongoDB query syntax for seamless database migration and use. Free, fast, and works entirely in your browser with no sign-up required.

Free .env File Generator

Generate .env files with common variables for different frameworks. Free, fast, and works entirely in your browser with no sign-up required.

Free JSON to Type Generator

Convert JSON to TypeScript interfaces, Go structs, or Rust types. Free, fast, and works entirely in your browser with no sign-up required.

Free Docker Compose Generator

Generate docker-compose.yml files with common services. Free, fast, and works entirely in your browser with no sign-up required.

Color Contrast Checker (WCAG)

Check WCAG 2.1 AA/AAA color contrast ratios for text, large text, and UI components. Live previews, APCA reference, accessible pair finder, and favorites.

CSS Flexbox Playground

Visually experiment with flexbox container and item properties. Generate CSS, Tailwind, and HTML output with live preview and presets for common layouts.

CSS Grid Generator

Visually design CSS Grid layouts with named areas, presets, and live code output for CSS, Tailwind, and HTML. Free, fast, and works entirely in your browser with no sign-up required.

CSS Animation Generator

Visually build @keyframes CSS animations with presets, live preview, cubic-bezier editor, and ready-to-copy CSS, SCSS, and Tailwind output.

Regex Cheatsheet Lookup

Searchable reference for 100+ regex tokens with live examples, common pattern library, inline tester, and cross-flavor notes for JS, Python, PCRE, POSIX.

SVG Optimizer

Shrink SVG files by stripping editor metadata, comments, default attributes, and excess precision. 100% client-side, no upload.

HTTP Request / cURL Builder

Visually build HTTP requests and export to cURL, fetch, axios, Node http, Python requests, PHP curl, Go net/http, and HTTPie.

Cron Expression Parser

Parse, explain, and preview cron expressions. See next run times, frequency, per-field breakdown, and minute/hour/day heatmaps.

Multi-Base Encoder / Decoder

Encode and decode data in Base16, Base32, Base58 (Bitcoin), Base64, Base64URL, and Base85 (ASCII85). Client-side with file upload support.

Favicon Package Generator

Generate a complete favicon package with all sizes, site.webmanifest, browserconfig.xml, and HTML snippet from a single image. ZIP download.

OpenAPI Spec Viewer

Parse and explore OpenAPI/Swagger specs with endpoint browsing, schema inspection, and cURL generation. Free, fast, and works entirely in your browser with no sign-up required.

SVG Path Editor

Parse, visualize, and transform SVG path d-attribute strings with live preview, editable command table, and path tools. Free, fast, and works entirely in your browser with no sign-up required.

GraphQL Query Builder

Visually build GraphQL queries, mutations, and subscriptions with dynamic field trees, variables, fragments, and live output.

Protobuf to JSON Schema

Convert proto3 definitions to JSON Schema, TypeScript interfaces, and sample JSON. Supports messages, enums, nested types, oneof, map, repeated.

Guides & tutorials

Step-by-step guides to get the most out of these tools.

The Developer's Toolkit: Essential Free Online Tools for 2026

About Developer Tools

Our Developer Tools collect the utilities that speed up day-to-day building. Test and inspect APIs, generate UUIDs and mock data, build and validate JSON schema, encode and decode tokens, look up HTTP status codes and Git commands, and more — a practical toolbox that runs entirely in the browser.

They're aimed at web and software developers, QA engineers, and students. Use them with our Code Tools for formatting and conversion, our Security Tools for hashing and encryption, and our Website Tools to test what you ship.

Related categories

Code Tools Security Tools Website Tools