UTILITY
User Agent API
/user-agentRead the User-Agent header sent with your HTTP request.
No signup or API key required.
Parameters
No endpoint-specific parameters. Use format to choose the response representation.
formatenumoptional · query- Response format. Defaults to json.
jsontext
No request body. Unknown or repeated query parameters return HTTP 400.
Returns 200 OK
A JSON object with the following fields.
user_agentstring- Raw User-Agent header, capped at 1024 characters. Empty if the header is absent.
Plain text
With format=text: Only the user_agent value, without the JSON wrapper.
Errors
Validation and service errors always return JSON, including when format=text.
errorstring- A machine-readable error code, such as invalid_parameter or rate_limited.
messagestring- A description of the problem.
400 Invalid parameters.
414 Query string exceeds 2048 characters.
429 Rate limit reached. Wait the seconds in Retry-After before retrying.
Usage notes
The raw User-Agent header, capped at 1024 characters. An absent header is an empty string.
Inspect what a browser or command-line client identifies itself as. This is the supplied header string, not a verified device identity or a browser detection service.
Responses are not cached. Browser requests are supported through open CORS.
120 requests per minute per IP, with up to 30 per 10 seconds, shared across APIs. Limits are approximate per Cloudflare location. Full usage limits ↗