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The Fuse API lets you drive the full Fuse workflow from your own systems: find prospects and companies, organize them into lists (searched, imported, or uploaded), enrich and validate contact data, attach AI smart columns, launch email and LinkedIn campaigns grounded in your knowledge hubs, run signal agents and deep research, and read the same analytics the app’s insights tabs show. Everything the API returns is plain JSON over HTTPS, authenticated with an API key you create in the Fuse app. If you have used APIs like Stripe or Anthropic, the shape will feel familiar: predictable resource-oriented paths, standard status codes, one error envelope everywhere, and rate-limit headers on every response. Prefer to drive Fuse from an AI assistant instead of code? The MCP server gives Claude, Cursor, and any other MCP client the same capabilities through natural language.

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Base URL

All endpoint paths in this documentation are relative to this base URL. The API is served only over HTTPS.

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A 30-second tour

Quickstart

Make your first request and build a list from a live prospect search in about five minutes.

Authentication

Create an API key and learn both accepted forms of the Authorization header.

Guides

Task-oriented walkthroughs: search, lists, custom columns, exports, and campaigns.

API Reference

Every endpoint with schemas, examples, and an interactive playground.

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What you can build

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Conventions used throughout

  • IDs are opaque strings ("68a1f20b9c41d20014b3e901"). Never parse or construct them.
  • Timestamps are ISO 8601 in UTC ("2026-07-27T10:00:00.000Z").
  • Success responses are keyed by the entity they carry — { "list": ... }, { "campaign": ... }, { "user": ... }. Paginated collections use { "data": [...], "pagination": ... } (pagination).
  • Errors always use one envelope with a stable machine-readable code (errors).
  • Asynchronous work (exports, saving search results, campaign initialization) returns 202 Accepted with an id you poll. Nothing long-running blocks a request.

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Need help?

Write to support@fuseai.com and include the request_id from any error response — it lets us trace the exact request in our logs.