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User-Agent

IANA permanent request RFC 9110 2 spellings

Declared by 82 providers across 5930 published specification files in the APIs.io network.

What this header is for, and how to use it →

A count here is providers whose published contract declares this header — not providers who send it. Response headers set at the edge rarely appear in an OpenAPI at all, so a low number can measure documentation practice rather than deployment.

Spelled 2 ways

HTTP field names are case-insensitive (RFC 9110 §5.1), so every spelling below is the same header on the wire. A contract is not the wire: generated clients key off the string, and a developer reading two of these sees two different headers.

User-Agentuser-agent

The registry

Statuspermanent
ReferenceRFC 9110, Section 10.1.5: HTTP Semantics

Providers declaring it (82)

adobe-suite affirm amplitude apifreaks-api-hub-for-developers apis-io balad-corp bancontact bazaarvoice brewpage bright-pattern brightcove cash-app chargebee cliniko clover coinme contentstack contextdev databento decart deliverect depict depictai eclipse engineering-platform expedia-group figure-technology-solutions finos github gocardless have-i-been-pwned helika helpscout hevn-inc intercom ipgeolocation jira just-eat keap keycorp klarna koala-io leonardo-ai lightspeed-pos line mailgun microsoft-azure moloco moogsoft mtn-group mycarrier national-weather-service noaa noaa-gov okta open-food-facts optimizely paystack plausible podcastindex postman punchh pydantic-ai ramp razorpay ringcentral sageox shutterstock small-improvements snowflake soveren spaitial-ai squarespace thingsboard todoist tollbit transmit-security ubuntu viator viridi-parente weather-gov worldpay

Explore

All headers Agent & Bot Identity Guidance on headers.apievangelist.com

Work with this as data

Every header here is available over the APIs.io API and to AI agents over MCP. HTTP Headers is not yet its own endpoint on the v1 API. Reach it through catalog search and the tag graph, or the MCP server.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for http headers

3 MCP tools reach this
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
Search the catalog
curl "https://apis.io/api/v1/search?q=user-agent&limit=10"
Everything under a tag
curl "https://apis.io/api/v1/tags/user-agent"

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