Build WhatsApp workflows with n8n

Connect OpenWA to n8n, an open-source workflow automation tool, using the official community nodes. By the end of this page you'll have the nodes installed, an OpenWA credential configured, and a working auto-reply workflow: an incoming WhatsApp message triggers a reply.

• npm package: @rmyndharis/n8n-nodes-openwa (current version 0.3.0)
• Repository: rmyndharis/OpenWA-n8n

The package ships two nodes:

Node	Type	What it does
OpenWA	Action	Calls OpenWA operations as a workflow step — send messages, check contacts, manage sessions and webhooks
OpenWA Trigger	Trigger	Starts a workflow when a WhatsApp event arrives — incoming messages, session and group events

Prerequisites

• A running OpenWA gateway that n8n can reach over the network. See Installation.
• A connected session that has finished pairing. See Your first session.
• An API key from the dashboard. See the Authentication guide.
• An n8n instance where you can install community nodes (self-hosted, or Cloud on a plan that allows them).
• An OpenWA server ≥ 0.2.8. The nodes are verified against v0.7.2.

Install the nodes

From the n8n UI (recommended)

1. In n8n, open Settings → Community Nodes.
2. Click Install.
3. Enter @rmyndharis/n8n-nodes-openwa and accept the community-node risk prompt.
4. Restart n8n.

Manual install

cd ~/.n8n/nodes
npm install @rmyndharis/n8n-nodes-openwa

Restart n8n after installing. Both nodes then appear in the node picker when you search for "OpenWA".

Configure the OpenWA API credential

Both nodes share one credential. Create it once and reuse it across every OpenWA node in your instance.

Field	Required	Default	Description
Server URL	Yes	http://localhost:2785	Your OpenWA server URL, without a trailing slash or /api. Use HTTPS in production (for example https://wa.yourserver.com).
API Key	Yes	—	The API key from your OpenWA dashboard. The node sends it as the X-API-Key header on every request.

When you click Test in the credential dialog, n8n makes an authenticated GET /api/sessions request to your server. The test passes only if the key is valid, so a wrong key or unreachable server fails immediately.

Use a scoped key

Create a dedicated API key for n8n rather than reusing an admin key, so you can revoke it without disrupting other clients. See the Authentication guide.

You can confirm the same credential by hand with curl before building a workflow. This hits the same send endpoint the Send Text operation uses, so a success here confirms both the credential and a connected session:

curl -X POST http://localhost:2785/api/sessions/default/messages/send-text \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "chatId": "628123456789@c.us",
    "text": "Hello from OpenWA!"
  }'

On success the gateway returns 201 Created with the message id and timestamp:

{
  "messageId": "true_628123456789@c.us_3EB0123456789",
  "timestamp": 1706868000
}

A 404 means the session id doesn't exist; a 400 means the session isn't connected or the body is invalid. Replace default with your session id and 628123456789@c.us with a real recipient chat id.

The OpenWA node (actions)

The action node maps a Resource and Operation to one OpenWA call.

Resource	Operation	Description
Session	Get Status	Get the status of a session
Session	List All	List all sessions
Message	Send Text	Send a text message
Message	Send Image	Send an image (binary, URL, or Base64)
Message	Send Document	Send a document or file
Message	Send Location	Send a location pin
Contact	Check Exists	Check whether a number is on WhatsApp
Contact	Get Info	Get contact information
Webhook	Create	Register a webhook (optional signing secret)
Webhook	Delete	Remove a webhook

See the n8n Node Reference for the full field-level detail of every operation. For any OpenWA endpoint not covered by the node — bulk send, reactions, group management — use n8n's generic HTTP Request node with the same X-API-Key credential. The complete endpoint list is in the API reference.

Base64 media needs a MIME type

When you send an image or document from a Base64 source, also set the MIME Type field (for example image/png or application/pdf) — OpenWA requires it for base64 payloads. The Binary source fills this in from the binary metadata, and the URL source needs nothing extra.

The OpenWA Trigger node (events)

The trigger node starts a workflow when a WhatsApp event occurs. When you activate the workflow, the node registers a webhook in OpenWA pointing at n8n's webhook URL; when you deactivate it, that webhook is removed. You never manage the webhook by hand.

Select one or more events to subscribe to:

Event	Description
message.received	New incoming message
message.sent	Message successfully sent
message.ack	Message delivery or read acknowledgement
message.failed	Message failed to send
message.revoked	Message deleted for everyone
message.reaction	Reaction added to or removed from a message (server ≥ 0.7.2)
session.status	Session status changed
session.qr	QR code generated for scanning
session.authenticated	Session authenticated
session.disconnected	Session lost connection

Message Reaction needs server ≥ 0.7.2

Selecting the message.reaction event against an older server returns a 400 when the webhook is created.

Reserved events

The group.join, group.leave, and group.update events are accepted when you subscribe but are not yet emitted by OpenWA. Don't depend on them until a release notes them as live.

Signature verification

The trigger has an optional Webhook Secret. When set, the secret is registered with OpenWA, and OpenWA signs every delivery with HMAC-SHA256 in the X-OpenWA-Signature: sha256=<hex> header. The node verifies each delivery against the raw request body and rejects any that fail with HTTP 401. Leave it empty to skip verification.

note

Changing or clearing the secret takes effect on the next activation. Deactivate and reactivate the workflow to re-register it.

Trigger payload

The trigger emits one item per event. The event is wrapped in an envelope; the actual event data lives under data:

{
  "event": "message.received",
  "timestamp": "2024-01-15T10:30:00Z",
  "sessionId": "default",
  "idempotencyKey": "a1b2c3d4e5f6",
  "deliveryId": "9f8e7d6c5b4a",
  "data": {
    "id": "3EB0F5A2B4C1",
    "chatId": "628123456789@c.us",
    "from": "628123456789@c.us",
    "body": "Hello!",
    "type": "text",
    "timestamp": 1705312200
  }
}

Reference fields in downstream nodes with n8n expressions — for example {{$json.data.body}} for the message text and {{$json.data.chatId}} for the chat to reply to.

A few notes from the payload contract:

• Read message fields from data (data.body, data.chatId), and the message identifier from data.id — incoming payloads use id, not messageId.
• type is engine-neutral: voice notes are voice, shared contacts are contact, and plain chats are text.
• Check Exists returns whatsappId, the engine-canonical chat id, which may differ from the number you sent (for example an @lid id).

Deduplicate retries

OpenWA retries failed deliveries with the same deliveryId. If your downstream actions aren't idempotent, add a dedup step (a Remove Duplicates node or an IF check) keyed on deliveryId so a retried delivery isn't processed twice.

Example: auto-reply to incoming messages

This is the smallest useful workflow — trigger on an incoming message, check the text, and reply.

1. OpenWA Trigger — select your OpenWA API credential and subscribe to message.received.
2. IF — condition: {{$json.data.body}} contains hello (case-insensitive).
3. OpenWA → Send Text — on the true branch, configure:
   • Session ID: default
   • Chat ID: {{$json.data.chatId}}
   • Message: Hi! Thanks for reaching out — how can we help?
4. Activate the workflow. The trigger registers its webhook with OpenWA automatically.

Send "hello" to your WhatsApp number, and you'll get the reply within seconds.

From here, swap the IF for a router to branch on keywords, append each new lead to Google Sheets before replying, or post a Slack alert when session.disconnected fires. The trigger gives you the inbound event; the action node sends the response.

Troubleshooting

Symptom	Cause	Fix
Credential Test fails	Server unreachable, wrong key, or a trailing slash in Server URL	Confirm the server is running and reachable from n8n, the key is correct, and Server URL has no trailing / or /api.
Trigger never fires	OpenWA can't reach n8n's webhook URL	Confirm n8n's webhook URL is reachable from the gateway (check firewalls and proxies) and that the session is connected.
Webhook creation fails with 400	message.reaction selected against a server older than 0.7.2	Upgrade OpenWA to ≥ 0.7.2, or remove that event from the subscription.
Send Text returns 400	Session not connected, or invalid chat id	Confirm the session status is ready and the chat id format is correct (628123456789@c.us).
Send Text returns 404	Session id doesn't exist	Set the node's Session ID to a real session.
Message sends but never arrives	Recipient isn't on WhatsApp	Use the Check Exists operation before sending to unverified numbers.

Next steps

• n8n Node Reference — every operation and field in detail
• Webhooks — the event model behind the trigger node
• Sending messages — every send operation and its fields
• API reference — every endpoint the action node can call
• n8n Community Nodes documentation — installing and managing community nodes