Anvil Tools
JSON Formatter & Validator
Pretty-print, minify, and validate JSON directly in your browser.
Open tool →User-Agent String Reference for Authorized Testing
Use these fixed browser and crawler strings as parser fixtures or request headers in an application you own or have permission to test. Copying a string does not change your browser, reproduce device behavior, or prove crawler identity. Respect access restrictions and verify actual crawler requests separately.
Get a user-agent string
Use fixed samples in a parser test
The fixture library was reviewed on October 5, 2026. Its Chrome 126, Firefox 127, and Safari 17.5 samples are intentionally fixed older examples, not claims about current versions. A selected string does not change your browser or authenticate a crawler.
| Input or check | Expected result or decision |
|---|---|
| iPhone Safari | Look for the iPhone, Version/17.5, Mobile, and Safari markers. |
| An unfamiliar user-agent string | Your application should retain a safe fallback instead of assuming a recognized browser. |
| Googlebot sample | Useful parser input; verify a real crawler separately before granting any special access. |
How it works
- Pick a browser or device from the list, or click random pick.
- The matching user-agent string appears in the box below.
- Copy a sample into a parser fixture or request-header test for an application you own or are authorized to test.
Common uses
- Testing recognized and unfamiliar client strings in your own application. Use real devices to test responsive rendering.
- Checking how your own parser handles a crawler sample without granting it special access.
- Reproducing a reported parser issue with a fixed input string. Test real browsers separately when behavior matters.
Your privacy matters here: check the FAQ below for exactly what happens to anything you enter into this tool.
Use samples for authorized testing
A user-agent string describes a client but does not make your browser emulate it. Use the samples to test parsing and display logic. Browser versions in these samples are illustrative, not a live release catalog.
A practical walkthrough
- Choose a browser sample and copy its user-agent string into a test fixture for your application.
- Test both recognized and unexpected strings so your application has a useful fallback.
- Copy the selected sample string into your authorized test environment. It does not change this browser or prove a crawler identity.
Tips for a reliable result
These are sample strings, not a live browser-version directory. Changing a string does not reproduce a browser engine or device.
What to use next
These tools open separately; inputs are not transferred.
UUID Generator
Generate cryptographically random RFC 4122 version 4 UUIDs.
Open tool →URL Encoder & Decoder
Encode text for a URL or decode percent-encoded values safely.
Open tool →Base64 Encoder & Decoder
Convert text to Base64 and back, entirely in your browser.
Open tool →How this tool handles your data
Reference strings are selected in your browser. No entered data is uploaded to an Anvil processing server.
Known limitations
A copied string does not emulate a device, change browser behavior, or prove crawler identity. Fixed samples can become dated as browsers change.
Related guide and Lab test
Questions and troubleshooting
Does picking a string change my real browser?
No. Copying a sample only gives you text. It does not change your browser, emulate a device, or establish a verified crawler identity.
What versions do the samples represent?
The browser examples include fixed Chrome 126, Firefox 127, and Safari 17.5 strings. They are parser fixtures, not a current browser-version directory.
What is an authorized use of these samples?
Use them only to test applications you own or have permission to test. Do not use them to evade access restrictions, misrepresent crawler identity, or generate deceptive traffic.
When a sample does not match your test
Select the intended browser or crawler sample, then check the receiving application's parser with that string. Samples do not update the browser's real identity or reproduce device capabilities. Use a real browser test when rendering behavior matters.
Does this change my browser identity?
No. It creates a sample text string for your test data. It does not change the current browser, emulate a device, or bypass access restrictions.
Are the samples the latest browser releases?
Treat the strings as examples, not a current release directory. Verify any exact version requirement separately and test real browsers when behavior matters.
Read the practical guide
Debug API Data with JSON, Base64, and Browser Tools
Work through JSON types, encoding, URL components, JWT claims, hashes, CSV conversion, and timestamps with small reproducible examples.