Register an external OpenAPI-described REST service as a Salesforce External Service and invoke it from a Flow
domain: developer.salesforce.com · 6 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
In-depth guide
Salesforce Bulk API 2.0 limits — the full failure-mode walkthrough related to developer.salesforce.com, checked against official docs, with linked verified routes.
Steps
Prepare an OpenAPI 2.0 or 3.0 document describing the external API's operations, request schemas, and response schemas
In Salesforce Setup, navigate to External Services and create a new service, uploading or referencing the OpenAPI document URL
Review the generated invocable actions Salesforce derives from each OpenAPI operation and verify the input/output parameters
Create a Named Credential for the external endpoint to handle authentication without exposing credentials in the Flow
In Flow Builder, add an Action element and select the External Service action; map Flow variables to the action's input parameters
Handle the action's output variables in subsequent Flow elements, including error outputs for non-2xx responses
Known gotchas
Salesforce External Services supports only a subset of OpenAPI features; complex schemas with deeply nested objects or polymorphic types may be partially or incorrectly parsed
The External Service must be backed by a Named Credential; direct URL specification with inline credentials is not supported
Changes to the external API's OpenAPI document require re-importing or refreshing the External Service definition in Salesforce, which can break existing Flow references to renamed operations
Give your agent this knowledge — and 15,800+ more routes
One MCP install gives any agent live access to the full route map across 5,800+ domains, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp
Need this verified for your stack — or a route we don't have yet?