Developer Tools
Formatters, encoders and debuggers for day-to-day engineering work. 11 free tools - every one runs entirely in your browser, nothing you paste in or upload ever leaves your device.
Formatters, encoders, and debuggers for day-to-day engineering tasks that don't need a full IDE - formatting and validating JSON, decoding a JWT, checking a site's SEO or security posture, and looking up DNS records a browser has no built-in way to query.
JSON Formatter
Clean, format, parse, and validate JSON inputs with instant syntax lint warnings and code export.
IP Address & Location Lookup
Find your public IP address, approximate location, ISP and timezone instantly.
Code to Image
Convert your raw code snippets into visually appealing, shareable screenshots with custom gradient frames.
Code Beautifier
Beautify, format, or minify your HTML, CSS, and JavaScript source files instantly.
Encoder / Decoder
Encode and decode standard Base64 translations, HTML escape entities, or URL navigation parameters.
JWT Debugger
Decode, verify, parse, and edit JWT token components including headers, payloads, and signatures.
Image to Base64
Convert local image file assets into raw base64 data-URL text strings for code embeddings.
SEO & Meta Tag Analyzer
Perform an instant SEO check. Validate meta titles, description lengths, heading tags hierarchy, and image alt tags.
Sitemap Validator
Check a sitemap.xml against the sitemap protocol - well-formed XML, valid URLs, lastmod/changefreq/priority formats, duplicate entries, and the 50,000-URL limit.
Security Header Checker
Check any site's HTTP response headers against security best practices - HSTS, Content-Security-Policy, clickjacking protection, Referrer-Policy, and more, with a graded scorecard.
DNS Lookup
Look up a domain's A, AAAA, CNAME, MX, TXT, NS, and SOA DNS records instantly.
Choosing the right tool
For payload and data debugging, JSON Formatter, JWT Debugger, Encoder/Decoder, Hash Generator, and Timestamp Converter are commonly used together in the same session. For site auditing, SEO Analyzer, Sitemap Validator, Security Header Checker, and DNS Lookup each check a different layer - content, crawlability, headers, and records - of the same site.
Common use cases
- Debugging a malformed API response or webhook payload
- Decoding a JWT to inspect its claims during an auth issue
- Auditing a site's SEO fundamentals or security headers before a launch
- Checking DNS, SPF, DKIM, or DMARC records during a domain or email migration
Developer FAQ
Do the URL-fetching tools send my code anywhere?
Only the tools that explicitly fetch a URL you provide - SEO Analyzer's URL mode, Security Header Checker, Sitemap Validator, DNS Lookup - make a server request, and only to retrieve that public page's HTML, headers, or records, never to store or log what you're debugging. Every other developer tool here is entirely client-side.