Offer call times in the prospect's own time zone with n8n

When a reply is labeled Interested, a webhook sends it to n8n, which works out the prospect's time zone, writes it to a custom field and asks the reply agent for a fresh draft that uses it.

AI agents

n8n

Cal.comFounderRevOpsTeam plan

When

Add LabelInterested

Then

Send a webhookSend the prospect id, signature, phone and thread URL to n8n, which sets custom_timezone and calls generate-reply

Why teams run it

Fewer back-and-forth emails to agree on a time.

Set it up in Master Inbox

In Master Inbox, open Settings, then Workflows, and click Add a workflow.
Name it Offer call times in the prospect's own time zone with n8n.
Set the trigger to Add Label and choose Interested.
Add the action Send a webhook: Send the prospect id, signature, phone and thread URL to n8n, which sets custom_timezone and calls generate-reply.
Save the workflow and switch it to Active.

Or create it with the API

Everything in the workflow builder is also in the Master Inbox API. This request creates the same workflow. Replace the example ids with your own label, list and campaign ids from GET /workflows/filter-fields.

curl -X POST https://api.masterinbox.com/api/api-webhook/v1/api/workflows/create-workflow \
  -H "Authorization: Bearer $MASTER_INBOX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "name": "Offer call times in the prospect's own time zone with n8n",
  "trigger_type": "add_label",
  "trigger_config": {
    "label_ids": [
      176479
    ]
  },
  "action_configs": [
    {
      "action_type": "webhook",
      "webhook_url": "https://hooks.example.com/master-inbox",
      "webhook_payload_variables": [
        "name",
        "email",
        "company_name",
        "label_names",
        "thread_url",
        "text"
      ]
    }
  ]
}'

Full reference: workflow API guide and API docs.

Or ask Claude, ChatGPT or Grok to build it

Our workflow guide is written for AI agents to read. Give your assistant your API key and this prompt:

Read https://app.masterinbox.com/public-workflow-api.md and use my Master Inbox API key to create this workflow: "Offer call times in the prospect's own time zone with n8n". First call GET /workflows/filter-fields and look up my label, list and channel ids, then create the workflow and tell me what you set up.

Questions

Which endpoints does n8n call?

PATCH /update-prospect for the time zone, then POST /reply-agent/generate-reply for the draft.

How long does generate-reply take?

It runs synchronously, so give the n8n step a generous timeout.

Can I build this workflow through the API?

Yes. Send the create-workflow request shown on this page with your Master Inbox API key. The API checks the payload first and lists every problem by field if anything is off.

Which plan includes this?

This workflow works on the Team plan. Every plan has unlimited users and starts with a free 7-day POC.