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Fake User-Agent String Generator

Every HTTP request carries a User-Agent header that servers inspect to detect device type and trigger bot-detection rules. Code that only ever sees Chrome 124 on Windows in tests can break silently when a Bingbot request arrives in production. Two inputs control the output. Count sets the batch size (1–30). Agent Type filters by category: browser produces Chrome, Firefox, and Safari on Windows and macOS; mobile produces Chrome on Android (Samsung and Pixel) and Safari on iPhone; bot generates Googlebot, Bingbot, DuckDuckBot, Baiduspider, and facebookexternalhit strings; any mixes all three pools. Version numbers reflect real browser release ranges — Chrome 90–120, Firefox 90–120, Safari 14–17, Android 10–14 — so they pass server-side pattern matching without raising flags. Note: modern bot-detection also inspects TLS fingerprints and timing. UA string rotation alone is not sufficient.

Read the complete guide — 4 min read

How to use

  1. Choose your options above
  2. Click Generate
  3. Copy your result

Detailed instructions

  1. Set the Count field to the number of User-Agent strings you need — use 5 for quick testing, 50 for a scraper rotation pool.
  2. Select an Agent Type from the dropdown: Any, Desktop Browser, Mobile Browser, or Bot to match your use case.
  3. Click Generate to produce the list of realistic User-Agent strings.
  4. Copy individual strings by clicking on them, or select all to paste the full list into your scraper config, test fixture, or load-testing tool.

Use Cases

  • •Rotating desktop and mobile User-Agent headers across Scrapy or httpx requests to reduce fingerprint consistency
  • •Testing server-side browser-detection logic in Express or Django to confirm correct content-type responses
  • •Populating Postman collection variables with realistic browser identities for API header testing
  • •Simulating Googlebot visits to verify robots.txt rules and dynamic rendering behavior in Next.js
  • •Seeding a k6 or Locust load-test config with mixed desktop and mobile client identities

Tips

  • →When building a scraper rotation pool, generate separate batches for desktop and mobile, then merge them — a mixed pool looks more like organic traffic.
  • →If you are testing a WAF rule, generate only Bot-type strings and confirm your server returns 403 or redirects as expected before going live.
  • →Pair each generated User-Agent with a matching Accept-Language header (e.g., en-US for Chrome on Windows) to reduce fingerprinting surface area.
  • →For load testing, generate a count equal to your simulated concurrent users so each virtual user gets a unique identity rather than sharing strings.
  • →Avoid reusing the same User-Agent string across multiple IPs in the same session — bot-detection systems correlate agent consistency with IP patterns.
  • →After generating strings, paste one into a User-Agent parser like ua-parser.github.io to confirm it decodes correctly before embedding it in production code.

FAQ

how do I use a fake user-agent string in Python requests

Pass it in the headers dictionary: requests.get(url, headers={'User-Agent': 'your_string_here'}). For rotation, store the generated list in a Python list and pick one per request with random.choice(). This gives you full control over which agent types appear in the pool.

will rotating user-agent strings actually prevent bot detection

User-Agent rotation is a useful first layer but not sufficient on its own. Modern detection systems also inspect TLS fingerprints, request timing, and cookie behavior. Pair rotation with realistic request delays, session cookies, and referrer headers for more durable scraper behavior. These strings are primarily useful for dev testing and middleware validation.

what is the difference between browser, mobile, and bot user-agent types

Browser strings mimic Chrome, Firefox, or Safari on desktop Windows or macOS. Mobile strings replicate Chrome on Android (Samsung Galaxy, Pixel) or Safari on iPhone, including device identifiers. Bot strings match known crawlers like Googlebot or Bingbot and usually include a URL to the bot's documentation. The any option draws from all three pools.

can I use bot user-agent strings to test how my server handles search engine crawlers

Yes. Selecting the bot type generates strings for Googlebot, Bingbot, DuckDuckBot, Baiduspider, and facebookexternalhit. Use them to verify that your robots.txt rules apply correctly and that your analytics correctly classifies bot traffic.

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