Prosopo Logo

Glossary

User Agent

A user agent is an HTTP header string identifying the client's browser, OS and device — trivially spoofed by bots, still useful when paired with TLS or JA4.

Analyze User Agents

Detect fake user agents and stop bot attacks

Start Detection

What is a User Agent?

A user agent is a string included in HTTP requests by browsers, bots, or other clients to identify themselves to web servers. It typically contains information about the client software, operating system, and device type. Web servers use user agent strings to deliver appropriate content, optimize compatibility, and analyze traffic. User agents play a key role in web development, analytics, and security.

Questions

Something else? Ask an engineer.

What is an User Agent?

A string sent by browsers or other clients to identify themselves and their capabilities to web servers.

Related terms

Ready to ditch Google reCAPTCHA?

Procaptcha is free for 10K requests a month. No credit card, no cookies.

Start free Protect a whole site →