Automation library · AI assistants

Secure AI agent webhook with HMAC and OpenAI

Started by another system calling it. It calls services over plain HTTP rather than through connectors. It hands the judgement calls to OpenAI. 11 steps, 2 branches: a working afternoon to understand properly.

MediumCalls a model: OpenAI

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11 stepsMedium: a working afternoon
2Branches: places the flow splits
0Loops or waits
0Services by connector: it calls them over plain HTTP

The flow

Starts it 3Model 2Logic 5Service 1

The steps in the order they run, from what starts it.

  1. 1OpenAI Chat ModelLm Chat Open AiModel
  2. 2WebhookWebhookStarts it
  3. 3AI AgentAgentModel
  4. 4Extract rawBodyCodeLogic
  5. 5CryptoCryptoService
  6. 6Timing-Safe HMAC CheckCodeLogic
  7. 7If2IfLogic
  8. 8Strict Payload ValidationCodeLogic
  9. 9Response to webhook : ForbiddenRespond To WebhookStarts it
  10. 10If1IfLogic
  11. 11Bad RequestRespond To WebhookStarts it

How it's built

Starts on
Another system calling it
Steps
11, with 2 branches
Size
Medium: a working afternoon
Connects to
Nothing by connector; it calls services over plain HTTP
Model
OpenAI

Questions

What does it need to run?

An n8n account, and a key for OpenAI. You connect your own accounts after importing it; none are included.

What starts it?

It starts on another system calling it.

Does it use AI?

Yes. It calls OpenAI. Model calls are billed by the provider, not by n8n.

How long does it take to set up?

Plan an afternoon. 11 steps is enough that you should read each one before running it.

How do I import it?

Copy the workflow, open a new workflow in n8n and paste. The steps appear on the canvas, ready for your own accounts.

Before you run it

Nothing here has been tested by us. It is somebody's working automation, read and described from its own steps. Treat the connections it wants as a list of accounts it will touch, and read the 11 steps before you point it at anything that matters.