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FabricGateways

Connect a REST API

Services connects plain HTTP APIs the same way you connect LLM providers and MCP servers. You add a connection, and then import an OpenAPI spec to generate its routes automatically. This topic shows you how to add a connection, import a spec, review the plan, publish it, and update the routes later.

Prerequisites

Before you begin, make sure you have the following:

  • Access to a Fabric AI Gateway organization, with permission to create connections.
  • An OpenAPI document for the API, in JSON or YAML.

Add a connection

You start from Create connection. To add a REST API connection, do the following:

  1. In the sidebar, select Services.
  2. Select Create connection. The Add connection page opens.
  3. Under the connection type, select the HTTP type that matches your API.
  4. To generate the connection and its routes from an OpenAPI document, select Import an OpenAPI spec, and then follow Import an OpenAPI spec.
  5. To add the connection yourself, enter a Name and the Target URL of your API, optionally set the Upstream auth requirement, and then select Add Connection.

Import an OpenAPI spec

Import an OpenAPI spec is a three-step wizard. It opens when you select Import an OpenAPI spec on the Add connection page.

Step 1: Provide the spec

Paste or upload a JSON or YAML OpenAPI document. Under Import mode, select one of the following:

Import modeBehavior
MergeAdds and updates routes from the spec, and leaves routes that aren’t in the spec untouched.
OverwriteMatches the spec exactly, and removes any routes that aren’t in it.

Optionally, expand Advanced settings to set the following:

  • Import ID — A stable identifier, so re-imports keep updating the same API instead of creating a new one.
  • Route prefix — Mounts every route from the spec under a path prefix. Fabric strips the prefix before it forwards the request upstream, so multiple imported APIs don’t collide.
  • Upstream URL override — Overrides the base URL for the upstream service.

Step 2: Review the plan

Review the plan before you publish anything. The plan shows which service Fabric creates or updates, how many routes are new, changed, or unchanged, and the exact route paths and methods.

Imported services don’t get gateway-managed authentication by default. Callers pass their own credentials through to the upstream unless you add an upstream credential on the Credentials page after you publish. For the steps, see Manage credentials and vaults.

Step 3: Publish

Click Publish to apply the plan.

Re-import to update routes

Re-importing an updated spec in Merge mode applies incremental updates. For example, adding a PUT operation to an existing path and adding a new path produces a plan that shows 1 new, 1 changed, and 3 unchanged routes, with an option to expand and view the unchanged ones.

Routes from multiple imports appear together under Services > Routes. For example, two services imported from the same spec at different times can contribute a combined 10 routes across albums, comments, posts (with both GET and PUT), todos, and users.

Next steps