Mill API & webhooks

Customer support.
Connected to
your tools.

Bring customer support into the systems you already use. Create tickets, send replies and keep your team in sync with one REST API.

Start building with Mill Explore the API

Every plan. The same API. Room to grow.

INTEGRATION OVERVIEW

CRMYour appAnalytics

MillAPI & webhooksConnected

ticket.createdYour workflow

message.createdYour system

01 Create & reply02 Assign & resolve03 Listen & sync04 Measure & grow

From a request to a result

Less copying.
More connected work.

Build your own connection between Mill and your CRM, internal tools or reporting pipeline. Your developer controls the workflow; your team keeps working in Mill.

Turn a request into a ticket

Create an email ticket from your app. Add a private description and choose whether to send a customer confirmation.

POST /tickets

Reply from your own tools

Send public replies to an existing chat or email ticket. Email responses use Mill’s delivery queue.

POST /messages

Keep your systems informed

Receive ticket, message and contact events. Fetch current data through the API for your downstream workflow.

Signed webhooks

Behind every API request, a real workspace

Your integration starts it.
Your team takes it forward.

Tickets created through the API join the same ticket workspace your operators use. Keep the customer conversation, owner and status in one place.

YOUR APP POST /tickets

YOUR TEAM Assign · Reply · Resolve

View the ticket workspace

Explore everything in Mill Tickets

Your integration control centre

Clear permissions.
Visible usage.

Create a separate key for each connection. Choose what it can read or change, track the company’s monthly usage and revoke access when it is no longer needed.

View full screen

Company-scoped keysSeven explicit permissionsNo automatic overage charges

Built for developers

Small requests.
Useful actions.

Standard HTTP methods. JSON payloads. Explicit scopes. A predictable starting point for your next integration.

Read contacts, chats, public messages and email tickets.
Create contacts and tickets, including tickets linked to a chat.
Send replies and update status or operator assignment.
List active agents and verified support mailboxes.

Open the developer guide in Mill

POST /tickets

curl https://app.mill.chat/api/v1/tickets \
  -H "Authorization: Bearer $MILL_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $REQUEST_UUID" \
  -d '{
    "mailbox_id": "YOUR_MAILBOX_UUID",
    "email": "maya@example.com",
    "subject": "Help with order #1042",
    "body": "Customer needs a delivery update.",
    "send_confirmation": true
  }'

POST /messages

curl https://app.mill.chat/api/v1/messages \
  -H "Authorization: Bearer $MILL_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $REQUEST_UUID" \
  -d '{
    "conversation_id": "YOUR_CONVERSATION_UUID",
    "body": "Thanks, Maya. We are checking your order."
  }'

PATCH /tickets

curl -X PATCH https://app.mill.chat/api/v1/tickets \
  -H "Authorization: Bearer $MILL_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $REQUEST_UUID" \
  -d '{
    "id": "YOUR_CONVERSATION_UUID",
    "status": "resolved",
    "assigned_to": "YOUR_AGENT_UUID"
  }'

Use a new UUID for each operation. Reuse it for identical retries.

Keep the next step moving

An event in Mill.
An action in your system.

Subscribe your HTTPS endpoint to customer support events. Verify each signature, then let your integration decide what happens next.

ticket.createdmessage.createdcontact.updatedconversation.updated

View full screen

Signed events

HMAC-SHA256 signatures and timestamps help your receiver verify where each event came from.

Retries with visibility

Up to eight delivery attempts. Inspect recent results, HTTP statuses and attempts in Mill. History is kept for 30 days.

Safe request retries

Idempotency keys protect new ticket, reply and update operations from accidental duplication. Results are retained for 30 days.

Included from day one

One API. Every plan.

Choose the monthly capacity that fits your integration. The operations and webhooks stay the same.

Starter

10,000API requests / month / companyCompare plans

Professional

50,000API requests / month / companyCompare plans

Business

100,000API requests / month / companyCompare plans

Scale

200,000API requests / month / companyCompare plans

60 requests per minute per company. Monthly usage resets on the first day of the month (UTC). Requests with a valid key and permissions count, including invalid parameters. HTTP 429 pauses API requests at the limit; your portal, chat and apps continue working. No automatic overage charges. Webhook deliveries do not use API requests.

Start with one useful connection

Three steps.
A connected workflow.

New to Mill? Start here

Create a scoped key

Open Settings → API & webhooks in your company. Select only the permissions your integration needs.

Make a server-side request

Keep your key on your server. Start with a read request, then add actions using the guide in Mill.

Connect your event receiver

Add an HTTPS webhook endpoint, verify signatures and test delivery. Deduplicate events and fetch the latest state.

The practical details

Questions,
answered.

Talk to Mill support

Is the Mill API included in every plan?

Yes. Starter includes 10,000 requests per month, Professional 50,000, Business 100,000 and Scale 200,000. All plans include the same API operations and signed webhooks.

What can I build with the customer support API?

Read contacts, conversations, public messages and tickets; create contacts and tickets; send replies; change status and assignment. You can also list active agents and verified mailboxes.

How are API limits counted?

Usage belongs to each company and is shared by its API keys. Requests with a valid key, permission and active company count, including invalid parameters. Monthly limits reset on the first day of the month in UTC. Each company also has a 60-request-per-minute limit.

What happens when I reach a limit?

The API returns HTTP 429 and a Retry-After header. There are no automatic overage charges. Your portal, chat and apps continue working. Webhook delivery attempts do not consume API requests.

How does Mill prevent duplicate replies?

New ticket, reply and status or assignment operations require an Idempotency-Key UUID. Retry an identical request with the same key to reuse its result. A different payload returns HTTP 409. Results are retained for 30 days.

How do I secure webhook events?

Verify the HMAC-SHA256 signature against the raw request body and timestamp using your endpoint secret. Reject old timestamps and deduplicate event IDs. Mill retries delivery up to eight attempts; events may arrive more than once or out of order.

Do I need a developer?

For a custom API connection, yes. Your developer creates a server-side integration using the guide in Settings → API & webhooks. This page describes the API; it does not imply a prebuilt connector for every CRM or workflow tool.

Make support part
of your bigger picture.

Connect the tools behind your customer experience.

Start free trial Find your plan

14 days. No credit card required.

Customer support.Connected toyour tools.

Less copying.More connected work.