Utilities that just work
Free online developer tools for JSON, JWT, Base64, regex, diffing, formatting, hashing, QR code generation, and HTTP header analysis.
What these tools cover
CodeAva tools are browser-based utilities built for the kinds of tasks that come up constantly during development: formatting a JSON response, decoding a JWT to inspect claims, comparing two text blocks, testing a regex pattern, or checking what headers a server is actually returning. Each tool is focused on one job and designed to give you a usable output immediately.
They are useful for developers reaching for a quick formatter or validator mid-session, QA engineers comparing payloads and testing input patterns, founders and technical site owners checking what their server is returning, and agencies reviewing client sites before or after launch.
Most tools process input locally in your browser using native browser APIs — nothing is sent to a server. A small number of tools, like the HTTP Headers Checker, make a server-side fetch to inspect the URL you provide. Each tool page notes what it does and does not transmit. No account or signup is required.
Developer tools by category
JSON Formatter & Validator
Beautify, minify, and validate JSON with syntax highlighting and clear error detection.
Base64 Encode / Decode
Instantly encode plain text to Base64 or decode Base64 strings back to readable text.
Hash Generator
Generate SHA-1, SHA-256, and SHA-512 hashes from any text input using Web Crypto.
Code Formatter
Format JavaScript, TypeScript, HTML, CSS, and JSON with consistent indentation rules.
Diff Viewer
Compare two blocks of text or code line-by-line with additions and deletions highlighted.
Regex Tester
Test regular expressions against sample text with real-time match highlighting.
JWT Decoder
Decode JSON Web Tokens — inspect header, payload, and signature without a secret.
HTTP Headers Checker
Fetch and inspect the HTTP response headers of any public URL in a clean, readable view.
Robots.txt Checker
Validate robots.txt syntax, test crawl rules by bot, and catch blocking mistakes that can hurt indexing.
Sitemap Checker
Validate XML sitemaps, inspect listed URLs, and uncover technical issues that reduce crawl and index efficiency.
What you can do with CodeAva tools
How these tools work