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flow-http-callout-action
Call external HTTP APIs directly from Flow using HTTP Callout actions (no Apex), handling auth, schema, and errors. NOT for registering an OpenAPI spec as an External Service — use flow/flow-external-services. NOT for Apex callout logic and mock tests — use apex/callouts-and-http-integrations.
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Flow HTTP Callout Action
Flow HTTP Callouts (GA) let admins call GET/POST/PATCH endpoints without Apex. You define the action against a Named Credential, supply a sample response for schema, and map inputs/outputs in flow variables. This skill covers auth, schema inference, pagination, and error handling.
Adoption Signals
Low-volume admin-driven integrations (weather lookup, address verification, single-record enrichment). Not for high-volume or complex transactions.
- Prefer <200 calls/day; switch to Apex callouts above that threshold to escape per-Flow concurrency limits.
- Required when the integration must run inside a screen flow without an admin-coded Apex dependency.
Recommended Workflow
- Create a Named Credential for auth (JWT, OAuth, or API Key).
- In Flow → New Action → HTTP Callout. Pick the NC, method, path.
- Provide a sample request + sample response; Flow infers the schema.
- Reference the action in your flow; map inputs and consume outputs.
- Add fault path on the action → handle 4xx/5xx (e.g., message screen on error).
Key Considerations
- Named Credential must be External Credential + Principal type — the old flavor doesn't work.
- Schema inference is rigid; complex nested JSON may require Apex wrapper.
- No automatic pagination handling — you loop.
- Transaction timeout applies to callouts inside record-triggered flows.
Worked Examples (see references/examples.md)
- Address verification — Lead capture
- Weather lookup — Field service dispatch
Common Gotchas (see references/gotchas.md)
- NC version mismatch — Callout fails auth.
- Complex JSON — Schema infer misses nested fields.
- No fault path — Flow fails to user.
Top LLM Anti-Patterns (full list in references/llm-anti-patterns.md)
- Apex for trivial GET
- Legacy Named Credential
- No fault path
Official Sources Used
- Flow Builder Guide — https://help.salesforce.com/s/articleView?id=sf.flow.htm
- Flow Best Practices — https://help.salesforce.com/s/articleView?id=sf.flow_best_practices.htm
- Reactive Screens — https://help.salesforce.com/s/articleView?id=sf.flow_ref_elements_screen_reactive.htm
- Flow HTTP Callout Action — https://help.salesforce.com/s/articleView?id=sf.flow_concepts_callout.htm