Is the User-Agent string sent to a server?

No. Parsing happens locally in your browser with bundled regex rules. The string never leaves the page.

Can I parse my own current User-Agent?

Yes. The tool offers a one-click option to fill the input with navigator.userAgent from the browser you are currently using.

Why does my UA show "Mozilla/5.0" even in Chrome and Safari?

The "Mozilla/5.0" prefix is a historical artifact from the 1990s browser wars. Nearly every modern browser keeps it for compatibility with legacy server-side sniffers.

Does it support User-Agent Client Hints (UA-CH)?

This tool parses the legacy User-Agent header string. Client Hints (Sec-CH-UA-*) are separate structured headers and require server-side inspection.

ua · browser · os · engine · device · live

Parse any User-Agent string

Break a User-Agent into browser, engine, OS, device, and bot flag. Runs entirely in your browser.

User-Agent Parser

Browser

Chrome

120.0.0.0

Windows 10/11

—

Device

Desktop

no model

Length

111 B

111 chars

input · user-agent

output · parsed

BrowserChrome 120.0.0.0

OSWindows 10/11

EngineBlink 537.36

DeviceDesktop

Bot / crawlerNo

Quick Start

How to parse a User-Agent

Paste a UA, get browser, engine, OS, device, and bot flag.

01
Paste a UA
Use one of the presets or your own browser's string.
Lookups reference the IANA registries (MIME, HTTP status, TLDs) bundled at build time — no live network calls, no rate limits, no leaked queries.
inputIANAregistryofflinelive
input · queryua · IANA
```
Mozilla/5.0 (Windows NT 10.0…)
```
loaded · IANA bundlespec · ready
02
Read the parsed fields
Browser name and version, OS, layout engine, device type.
Builders emit canonical syntax per the relevant RFC (9110 for HTTP, 5322 for headers, 3986 for URLs) so the output passes spec-compliant parsers.
fieldsRFC 9110canonicalspec-compliantlive
parsed · options5 · live
```
Chrome 120 / Windows 11
```
options applied · livecanonical
03
Spot bots and crawlers
Known bot tokens (Googlebot, Bingbot, AhrefsBot…) flip the bot flag.
Validation flags common pitfalls — uppercase header names, smart quotes inside Content-Type, missing ;charset=utf-8 — before they bite production.
botsvalidationlintpitfallslive
bot · looked uptrue · ready
```
Googlebot/2.1 → bot: yes
```
result · livevalidated
04
Copy or download
Grab the parsed summary as a one-paragraph block.
Copy writes the snippet directly into your clipboard; downloads emit the right extension and MIME so curl/httpie pick them up correctly.
exportclipboardMIME-correctblobcurl-ready
ok · copiedready · done
```
Copied
```
shipped · ready to shipsuccess

Pro tips

Web-spec details that bite later

Idempotency saves retries

POST/PUT/DELETE should be safely retried. Use idempotency keys and return the same response on duplicate requests.

Match RFC 9110 status codes

Don’t invent codes. 422 for validation errors, 409 for conflicts, 429 for rate limits. Standard codes work with off-the-shelf clients.

Set <code>Cache-Control</code> deliberately

Default browser caching is conservative. Use max-age + stale-while-revalidate for hot endpoints.

Validate Open Graph in dev

OG tags break silently. Use a previewer like OG Generator + Facebook’s debugger before launch.

CORS is a server concern

The browser sends the preflight; the server decides. Wildcard origins disable credentials — be explicit.

MIME drives behaviour

Servers must send the right Content-Type. Browsers sniff but the spec says they shouldn’t — be explicit to avoid surprises.

Use Cases

When to parse a User-Agent

Analytics, bot filtering, support tickets.

Analytics segmentation

Roll up requests by browser family. Bundled from IANA registries at build time — no live network call, no rate limit, no leaked queries. The MIME, TLD, and status-code tables are baked in so the tool works offline once loaded.

spec-compliant

Bot filtering

Drop crawler hits from product metrics. Output is canonical per the relevant RFC (9110 for HTTP, 5322 for headers, 3986 for URLs), so spec-compliant parsers accept it as-is. Cross-browser and cross-library behaviour stays consistent.

offline

Bug triage

Get the user's browser + OS from a UA in a ticket. Pairs with the curl-to-fetch converter for end-to-end test stubs — copy the curl from DevTools, paste, get an idiomatic fetch() body. Drop into Playwright/Vitest fixtures without manual translation.

IANA-backed

Feature flagging

Light client-side branching on engine. Catches common pitfalls (uppercase header names, smart quotes inside Content-Type, missing ;charset=utf-8) before they bite production. Validation flags rather than auto-corrects so you stay in control.

RFC-aligned

Compatibility

Pair with the BrowserStack matrix. Validation runs as you type — copy only when the output is shaped correctly. The output drops directly into nginx, Apache, or CDN configs without re-formatting or re-quoting.

production-grade

Server-side rendering

Pick mobile vs desktop bundles. Same input plus same options always produces identical canonical output, so the tool is safe to embed in CI scripts that diff against expected configs.

curl-ready

FAQ

Frequently asked questions

Is UA parsing reliable?

Reasonably for browsers and big bots, but UAs are spoofable and Apple/Google now freeze parts of them. Prefer Client Hints when possible.

Why does Edge show Chrome in the UA?

Edge uses the Chromium engine and includes the Chrome token for compatibility. We detect the Edg/ token first.

Why doesn't Safari report the version directly?

Apple's Safari UA includes Version/ as the browser version and WebKit/ as the engine. We use the former.

Can you detect Chrome on iOS?

Chrome iOS uses the same WebKit-based UA as Safari (with a CriOS token). We surface that as Chrome.

Is anything sent to a server?

No — parsing runs locally in your browser.

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