User Agent Parser
The User-Agent header is the messy, free-form string browsers send to identify themselves. This parser uses pragmatic regex matching (the same approach as ua-parser-js) to extract the browser name + version, rendering engine, OS + version, device type/vendor/model, and CPU architecture. Auto-fills with your current browser's UA on load. Useful for analytics debugging, bot identification, and understanding what your server logs are seeing.
Paste a User-Agent string above.
Parsing runs entirely locally. Regex-based — same approach as ua-parser-js, with simpler rules and recent bot signatures (GPTBot, ClaudeBot, PerplexityBot).
How to use
- By default, your own browser's User-Agent is parsed.
- Click 'Use current' to refresh from `navigator.userAgent`, or paste any UA string.
- Read the parsed fields. Bots get a special highlight.
Frequently asked questions
- Why are user-agent strings so weird?
- Historical compatibility hacks. Every browser pretends to be 'Mozilla/5.0' because old servers gated content on that string. Chrome adds 'Safari' because old WebKit detection used that. The cargo cult never ends.
- Will Client Hints (UA-CH) replace this?
- Slowly. Chrome is freezing UA contents (User-Agent Reduction) and offering structured Client Hints headers (Sec-CH-UA-*) as the replacement. For now, both coexist. This parser works on the legacy UA string.
- How accurate is bot detection?
- Reliable for honest bots (Googlebot, Bingbot, GPTBot, ClaudeBot — they identify themselves). Useless against bad-faith bots that spoof a desktop Chrome UA. For those you need behavioral fingerprinting or CAPTCHAs.
- Why doesn't it show device model on iOS?
- iOS user agents have not included a specific model since iOS 13 — they all say 'iPhone' or 'iPad'. Apple deliberately strips this for privacy. Server-side, you'd use a separate Client Hint or the screen dimensions to guess.
Related tools
robots.txt Tester
Paste a robots.txt and a list of (user-agent, path) pairs to see exactly which line allows or blocks each — with longest-match precedence, wildcards, and the * group fallback.
Permissions-Policy Header Builder
Build the `Permissions-Policy` response header — toggle camera, microphone, geolocation, payment, fullscreen and 20+ other browser features by origin allowlist.
Email Header Analyzer
Paste a raw email header to walk the Received hops in order, see the per-hop delay, and read off the SPF/DKIM/DMARC verdicts.
DKIM Record Builder & Parser
Build or parse a DKIM (DomainKeys Identified Mail) DNS TXT record — paste your public key, pick selector, key type (RSA/Ed25519), hash and flags, get the full record plus the selector._domainkey hostname and a DNS-chunked version for records over 255 chars.
Sitemap.xml Validator & Inspector
Paste or load a sitemap.xml (or a sitemap-index .xml) and instantly see URL count, size, spec compliance, and distributions of changefreq, priority and host — entirely in your browser.
RSS & Atom Feed Viewer
Paste a feed and read it: entries, dates normalised, podcast enclosures, and the problems that make readers drop or duplicate posts.