Developer Tools
Parse a User Agent String
Transform pasted text with the user agent parser and copy the cleaned output.
Direct Answer
Use the User Agent Parser when you have a raw user-agent string from a request log, analytics tool, or browser and need to know the browser, version, operating system, or device type it represents.
Why User-Agent Strings Look So Messy
Nearly every modern browser's user-agent string is full of legacy tokens that exist purely for backward compatibility with old server-side sniffing logic, rather than accurately describing the browser.
- Chrome, Firefox, Safari, and Edge all include "Mozilla/5.0" for historical reasons, even though none of them are the original Mozilla browser.
- Most browsers also include "like Gecko" or reference other engines even when they don't actually use that rendering engine.
- Chrome-based browsers often include "Safari" in their UA string because early sites checked for that token to enable modern features.
- The result is a string that looks like it identifies multiple browsers at once, when really only the last meaningful tokens reliably identify the actual browser and version.
What Parsing Can and Cannot Tell You
A parsed user agent is useful for analytics and rough compatibility checks, but it's not a reliable signal to build security or critical functionality decisions on.
- User-agent strings can be freely spoofed by the client, so they should never be trusted for authentication or access control.
- Feature detection (checking whether an API actually exists) is more reliable than UA sniffing for deciding whether a browser supports something.
- Bots and crawlers often use identifiable UA strings, but a well-behaved scraper can just as easily copy a real browser's UA string to blend in.
- Newer browsers increasingly send a frozen or reduced UA string, shifting detailed capability information to User-Agent Client Hints instead.
How to Use User Agent Parser
- Paste or type your content into the input box.
- The transformed result appears instantly in the result panel below.
- Click Copy result to copy the output to your clipboard.
- Download .txt saves the transformed text as a file.
- Reset clears everything and lets you start over.
Reference
| Feature | Details |
|---|---|
| Purpose | Transform pasted text into a cleaner or different format. |
| Input | Text, lines, lists, or copied content. |
| Result | Transformed text ready to copy or download. |
| Best for | Cleanup, formatting, list preparation, and copy-paste workflows. |
| Category | Developer Tools |
| Works on | Desktop, tablet, and mobile browsers |
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A Focused User Agent Parser Alternative
People looking for alternatives to JSONLint, Code Beautify, FreeFormatter, Browserling often want a simpler workflow. This user agent parser focuses on the task first: clear inputs, a visible result, useful related tools, free access, and no account requirement.
- Puts the tool input and result near the top of the page
- Free to use with no account or payment step
- Includes focused explanations and related tools
- Designed to avoid misleading download buttons and forced interstitials
Useful Related Tools
Frequently Asked Questions
Why does Chrome's user agent contain 'Mozilla/5.0'?
It's a historical artifact from the browser wars, when sites checked for "Mozilla" to serve advanced content to Netscape. Every major modern browser, including Chrome, Firefox, and Edge, still includes this token purely for backward compatibility with old sniffing scripts, even though none of them are Mozilla's original browser.
Why does the UA string mention Safari when I'm not using Safari?
Chrome and other Chromium-based browsers include "Safari" in their user-agent string because early WebKit-based feature detection checked for that token. It's another compatibility holdover, not an indication that Safari is actually involved.
Can a user-agent string be faked or spoofed?
Yes, completely. Any client can send any UA string it wants, since it's just an HTTP header the browser or script chooses to set. This is exactly why UA strings should never be relied on for security decisions.
Should I use user-agent sniffing to detect browser features?
No, feature detection (directly checking whether a specific API or property exists in the browser) is more reliable, since UA strings are inconsistent, spoofable, and get more confusing with every added compatibility token. UA sniffing is better suited to rough analytics than to making functional decisions in code.
How do I tell a bot or crawler apart from a real user in a UA string?
Legitimate crawlers like Googlebot or Bingbot typically identify themselves clearly, often including the word "bot" and a URL to more information. However, this isn't a security check; a scraper with bad intentions can just as easily send a normal browser's UA string to avoid detection.
What's the difference between a mobile and desktop UA string?
Mobile UA strings typically include tokens like "Mobile", "Android", or "iPhone" along with the specific OS version, while desktop strings reference "Windows", "Macintosh", or "Linux" instead. Some sites use these tokens to decide whether to serve a mobile-optimized layout, though responsive design and feature detection are generally more reliable.
What does 'like Gecko' mean in a UA string?
Gecko is Firefox's rendering engine, and "like Gecko" is another legacy compatibility token that many non-Gecko browsers include so that old scripts checking for it still behave correctly. It doesn't mean the browser actually uses Gecko.
Why do some browsers send a 'frozen' or reduced user agent now?
To reduce fingerprinting for privacy, some browsers have started freezing or truncating the detail in their UA strings, such as reporting a generic OS version instead of the exact build. Detailed information that used to come from the UA string is being moved to an opt-in mechanism called User-Agent Client Hints instead.
Can I trust the operating system version reported in a UA string?
Not entirely; some browsers report a frozen or generic OS version rather than the exact one installed, especially on newer privacy-focused releases. It's a reasonable approximation for analytics but shouldn't be treated as an exact, verified value.
Why does an in-app browser, like Instagram's or Facebook's, have a distinct UA string?
In-app browsers (WebViews embedded inside a native app) typically append their own identifying token to the underlying browser engine's UA string, such as adding "Instagram" or "FBAV" to a WebKit-based UA. This lets sites detect the more limited WebView environment, which sometimes lacks features or has different behavior than a full browser.
What is User-Agent Client Hints (UA-CH) and how does it relate to the old UA string?
UA-CH is a newer, opt-in mechanism where a server explicitly requests specific details (browser, platform, mobile status) through headers rather than parsing them out of one long string. It's meant to eventually replace detailed UA string sniffing with a more structured, privacy-conscious alternative.
Why might two completely different browsers report an almost identical UA string?
Because so many tokens exist purely for cross-browser compatibility rather than genuine identification, two Chromium-based browsers (like Chrome and Edge) can look nearly identical except for one or two distinguishing tokens near the end of the string. Parsing has to look at the specific, meaningful tokens rather than the string as a whole.
Why do server-side UA parsing libraries need constant updates?
New browser versions, new devices, and new compatibility tokens are released constantly, and a parsing library's rules can become outdated or misidentify a browser as new UA formats appear. This is a common maintenance pain point for any analytics or logging pipeline that depends on accurate UA parsing.