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Free Developer Tools — 44 Tools, No Signup Required

JSON Formatter & Validator

Format, validate, minify, and convert JSON — with tree view, diff tool, and auto-fix for common errors

Base64 Encoder & Decoder

Encode and decode Base64 text, files, and images instantly — with data URI output and live preview

URL Encoder & Decoder

Encode, decode, and parse URLs with a visual breakdown of every component

Hash Generator & Checksum Tool

Generate MD5, SHA-1, SHA-256, SHA-512 hashes for text and files — with HMAC and checksum verification

Regex Tester & Debugger

Test, debug, and visualize regular expressions in real-time — with a common patterns library and plain-English explainer

UUID Generator

Generate UUID v1, v4, v7 individually or in bulk. Decode existing UUIDs. Copy, download, format options.

Cron Expression Generator

Build and decode cron expressions visually. See next run times, plain-English descriptions, and common presets.

JSON ↔ CSV ↔ YAML

Convert between JSON, CSV, and YAML instantly. Handles nested objects, configurable flattening. Download results.

Slug Generator

Convert any text to a clean URL slug. Bulk mode, accented character support, configurable options. Free, instant.

Subnet Calculator

Calculate subnet mask, network/broadcast address, host range from any IP + CIDR. VLSM mode. Binary breakdown.

PX to REM Converter

Convert pixels to rem and back. Bulk CSS converter, customizable root size, reference table. Free, instant.

Color Code Converter

Convert between HEX, RGB, HSL, CMYK, and CSS named colors instantly. Color wheel picker, bulk CSS converter. Free.

CSS/JS/HTML Minifier

Minify or beautify CSS, JavaScript, and HTML. See file size reduction. Swap, download, auto-detect language. Free.

Markdown to HTML Converter

Convert Markdown to HTML with live preview. Full GFM support: tables, task lists, code blocks. Bidirectional. Free.

JSON Viewer

Paste JSON and explore it as an interactive collapsible tree. Color-coded types, JSONPath, search. Free.

PPI Calculator

Calculate pixel density from resolution and screen size. Device comparison, design asset recommendations. Free.

Code Diff Checker

Compare two code blocks with syntax highlighting. Side-by-side and unified views. Character-level diffs. 20+ languages. Free.

JSON to TypeScript

Paste JSON, get TypeScript interfaces instantly. Nested objects, arrays, optional fields, union types. Download .ts file. Free.

Unix Timestamp Converter

Convert Unix timestamps to human-readable dates and back. Supports seconds, milliseconds, nanoseconds. Batch conversion, time zones. Free.

Epoch Converter

Convert epoch timestamps to dates and vice versa. Seconds, milliseconds, nanoseconds. Batch mode and time zone support. Free.

JWT Decoder

Decode and inspect JSON Web Tokens. View header, payload, claims. Check expiration, verify signatures. Free JWT decoder.

JWT Token Decoder

Decode JWT tokens, inspect claims, check expiration and signature. Debug authentication issues. Free online tool.

SQL Formatter

Format and beautify messy SQL queries. Uppercase keywords, proper indentation, handles subqueries. Download .sql files. Free.

SQL Beautifier

Beautify SQL queries with configurable formatting. Keyword casing, indent size, line width. Supports all SQL dialects. Free.

API Request Tester

Send HTTP requests and inspect responses. Lightweight Postman alternative with code generation, history, auth. Free.

API Request Tester

Test API endpoints from your browser. GET, POST, PUT, DELETE with headers, body, auth. Generate cURL, JS, Python code. Free.

DNS Lookup

Look up DNS records for any domain — A, AAAA, MX, TXT, NS, CNAME, SOA. Cloudflare DNS-over-HTTPS. Export results. Free.

Domain Lookup

Query DNS records for any domain. See IP addresses, mail servers, nameservers, TXT records. Real-time results. Free.

AI Code Explainer

Paste any code and get a clear AI explanation. Supports JavaScript, Python, SQL, React, and 15+ languages. Line-by-line or overview. Free.

Explain Code

AI-powered code explanation tool. Paste code in 15+ languages and get instant plain-English explanations. Beginner and developer modes. Free.

Code to Image

Turn code into beautiful images with syntax highlighting, gradient backgrounds, and window chrome. Free.

Code Screenshot

Generate beautiful code screenshots. 30+ themes, 40+ languages. Like Carbon.sh but free and unlimited.

Meta Tag Generator

Generate SEO meta tags, Open Graph, Twitter Cards, and Schema.org. Live Google/Facebook/Twitter preview. Free.

SEO Meta Tags

Free meta tag generator with real-time search and social preview. Open Graph and Twitter Card support.

AI Code Reviewer

Paste code for AI-powered review. Bugs, security, performance, style analysis with score 0-100 and suggested fixes. Free.

Code Review Tool

Free AI bug finder and security scanner. Analyzes code in 20+ languages with severity ratings and line references.

AI Roast My Website

Get a brutally honest AI critique of your website. 6 categories, witty roasts, actionable fixes. Shareable roast card.

Website Critique

Free AI website review. Design, copy, CTAs, mobile, SEO, trust scored with specific improvement suggestions.

Wireframe Builder

Drag-and-drop wireframe tool with 30+ UI components. Phone, tablet, desktop frames. Export PNG/SVG/PDF. Free.

Wireframe Maker

Free wireframe maker for website and app UI planning. Pre-built components, annotations, multi-page. No signup.

AI Prompt Generator

Build perfect prompts for ChatGPT, Claude, and any AI. 12+ templates for code review, debugging, writing, data analysis. Free.

Prompt Builder

Generate structured AI prompts from templates. Fill in the blanks, copy, paste into any AI tool. Free, no signup.

CSS Box Shadow Generator

Visual CSS box-shadow editor. 12 presets, multiple layers, live preview. Copy CSS and Tailwind. Free.

Box Shadow CSS Generator

Create CSS box-shadow effects visually. Material, Neumorphism, Glow presets. Copy CSS or Tailwind. Free.

About Developer Tools

Developer tools are the everyday utilities that software engineers reach for dozens of times a day. With over 27 million software developers worldwide and that number growing by roughly 500,000 each year, the demand for fast, reliable, browser-based dev tools has never been higher. Instead of installing CLI utilities or signing up for yet another SaaS product, you can format JSON, test regex patterns, generate UUIDs, and encode Base64 right here in your browser.

Our 44 developer tools are built by developers, for developers. Each tool is designed to handle real-world edge cases: the JSON formatter auto-fixes trailing commas and unquoted keys, the regex tester explains patterns in plain English, and the hash generator supports HMAC authentication. Everything runs client-side with zero server calls, so you can safely paste API keys, tokens, and production data without worry.

Whether you are debugging a webhook payload, calculating subnets for a network configuration, building cron schedules for your CI pipeline, or converting between data formats, these tools are designed to be faster and more capable than any alternative you will find online. Bookmark this page and stop wasting time searching for the same utilities over and over.

Last updated: March 2026

Frequently Asked Questions

Do these developer tools work offline?

All of our developer tools run entirely in your browser using JavaScript. Once the page has loaded, most tools will continue to work even if you lose your internet connection. Your data never leaves your device, making them safe to use with sensitive code and credentials.

Can I use these tools with production data?

Yes. Since everything runs client-side in your browser, no data is ever sent to a server. This makes our tools safe for production API keys, tokens, and sensitive JSON payloads. You can verify this by checking the Network tab in your browser's developer tools.

How does the JSON formatter handle large files?

The JSON formatter is optimized to handle files up to several megabytes in size. It uses efficient parsing algorithms and virtual rendering for the tree view, so even deeply nested JSON with thousands of nodes remains responsive. For extremely large files (50MB+), consider using a desktop tool.

What regex flavors does the regex tester support?

The regex tester uses JavaScript's built-in RegExp engine, which supports all modern regex features including lookbehind assertions, named capture groups, Unicode property escapes, and the dotAll flag. This covers the vast majority of use cases for web development, data validation, and text processing.

Are the UUID v7 values compliant with the RFC 9562 standard?

Yes. Our UUID generator produces RFC 9562-compliant UUIDs for all supported versions. UUID v7 values are time-ordered, using a Unix timestamp in the most significant bits, making them ideal for database primary keys where sort order matters.

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