120+ Free Online Developer Tools — No Sign-up, Runs in Browser

DevTools Online is a free collection of 120+ online developer tools built for software engineers, web developers, and digital creators. Every tool runs entirely in your browser — no sign-up required, no data leaves your device, and no tracking. Whether you need to format JSON, beautify SQL queries online, decode a JWT token, or generate a QR code, DevTools Online has you covered in seconds.

JSON Formatter, Validator & Converter Online

Format and beautify JSON online, validate JSON structure, minify JSON for production, and diff two JSON objects side by side. Convert JSON to C# classes, TypeScript interfaces, CSV, YAML, or XML in one click — free, no login required.

SQL Formatter Online — Beautify, Convert & Visualize SQL

Free SQL formatter online for SELECT, INSERT, UPDATE, DELETE, and DDL statements. Convert SQL to C# LINQ, visualize SQL execution plans, and generate ERD diagrams from CREATE TABLE scripts — all in your browser.

Base64 Encoder Decoder, JWT Decoder & Hash Generator

Encode and decode Base64 strings, URLs, and HTML entities online. Generate MD5, SHA-256, SHA-512, and BCrypt hashes instantly. Decrypt and encode JWT tokens, AES-256 encryption — all client-side, no data sent to any server.

DNS Lookup, SSL Certificate Checker & IP Geolocation Online

Look up DNS records, check SSL certificates online, inspect HTTP headers, parse user-agent strings, geolocate IP addresses, and calculate CIDR subnets — all free, instant, no installation needed.

XML, YAML, HTML & CSS Formatter — Online Code Beautifier

Format and beautify XML, YAML, HTML, CSS, and Markdown online. Minify JavaScript and CSS for production. Preview Mermaid diagrams and build ERD schemas directly in your browser — free developer tools, no account needed.

UUID Generator, QR Code Generator & Password Generator Online

Generate UUIDs, NanoIDs, secure random passwords, QR codes, barcodes, favicon sets, fake test data, and TOTP 2FA codes — all free, available online without any account or installation.

Privacy-First Developer Tools — 100% Client-Side

All DevTools Online tools run entirely client-side in your browser. No servers receive your data, no accounts required, no usage tracked. Your sensitive data — passwords, tokens, keys — stays private at all times.