User-Agent

Identifies the client application (browser, bot, or custom). Servers may use it for analytics or content negotiation.

Request

Syntax

User-Agent: <product>[/<version>] [<comment>]

Value	Explanation
Mozilla/5.0 (Windows NT 10.0; Win64; x64) Chrome/120.0	Chrome on Windows
MyApp/1.0 (https://example.com)	Custom API client
curl/8.0	curl default

curl -H "User-Agent: MyApp/1.0" https://api.example.com

Spoofing browser UA for non-browser clients; blocking based on UA alone.