n8n and WhatsApp: a message flow with Evolution API

n8n does not talk to WhatsApp on its own. The usual flow puts Evolution API in the middle: it is the bridge to WhatsApp, and n8n is the brain. When a message arrives, Evolution API tells n8n by webhook; to reply, n8n makes an HTTP request to Evolution API. Both are third-party programs you run on a VPS of your own.

There is a risk worth knowing about. With the QR code connection (Baileys), the WhatsApp link is unofficial: the number can be blocked, especially if you send a lot, or to people who did not ask. Read Baileys or the Cloud API: the risk and the rules before putting real customers on this flow.

The two directions

Direction How it is done In n8n
Receiving a message In Evolution API you point the instance webhook at the n8n production address and choose the incoming-messages event. A Webhook node as the trigger.
Sending a message n8n calls the Evolution API send endpoint, with the API key in a header and the number and text in the body. An HTTP request node.

The exact endpoint names and fields change with the Evolution API version. Use its documentation for your version, not an example copied from an old tutorial. Evolution API itself is covered in installing Evolution API with Docker Compose.

Building the flow

1 Put both on the same VPS, on the same Docker network. Inside a container, localhost is the container itself, so n8n calls Evolution API by the service name in the compose file, not by localhost.
2 Create the instance and connect it with the QR code. See sending your first message with Evolution API.
3 Create the workflow with a Webhook node and copy the production address into Evolution API. The test one only works while you design. See n8n webhooks.
4 Ignore the messages the instance itself sent. The incoming data says whether the message is yours. Without that filter the workflow answers its own replies, in an endless loop.
5 Reply with an HTTP request node to Evolution API. Keep the API key in the n8n credential, never typed into the workflow.
6 Add pauses and limits. Avoid sending many messages in a row to different numbers.

When it does not work

Symptom Likely cause
The workflow never starts Evolution API is posting to the test address, or the workflow is inactive.
The send request gives a connection error You used localhost instead of the service name, or the containers do not share a network.
401 or 403 from Evolution API The API key is not going in the header, or it is the wrong one.
Works, then stops The instance disconnected from WhatsApp. See the instance stuck on “connecting”.
The same flow, step by step, is in Evolution API and n8n: a working flow. To protect Evolution API, see securing Evolution API.

Need a VPS to run n8n and Evolution API?

See the VPS servers

SEE ALSO

What Evolution API is

Evolution API and n8n: a working flow

Receiving messages: Evolution API webhooks

WhatsApp for business: the risks, and the practices that avoid them

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