Search the web

Linkup

Web search API with its own index that returns ranked sources and snippets, cited answers or structured JSON.

Methods

Method	Used for	How
API key	REST API, SDKs, CLI	`Authorization: Bearer <YOUR_LINKUP_API_KEY>` header
API key	Remote MCP server	`Authorization: Bearer` header, or `?apiKey=` query parameter
x402 (USDC on Base)	`/v1/search` and `/v1/fetch` without an account	Send request, get `402`, resend with signed payload in `payment-signature` header

Source2Authentication

Getting access

Who creates the account: A person creates an account to get a key; agents can instead pay per request with x402 and no account11
Where to get a key: Linkup app at https://app.linkup.so2
Other requirements: Professional email address for the sign-up credit; USDC wallet on Base for x4021

Read from Linkup’s own pages on 2026-11-04. Every number links to the page a value came from. For agents, the same facts as markdown: /tools/search-the-web/linkup.md