iMessage API for SaaS: a sub-account and number for each customer

Which iMessage APIs create a sub-account and number per customer?

Checked 6 November 2026 on each provider's own documentation and pricing pages. “Not published” means the provider does not list the figure.

How does Claw Messenger Agency work for a SaaS?

1. Request access. Email what each customer's assistant will send and receive and roughly how many customers you start with. Agency is invite-only.
2. Onboard once. You get a single-use signup link, pay the $250 onboarding and save a card. Your parent API key appears in the dashboard.
3. Create a sub-tenant per customer. When a customer turns on texting, your backend calls the create endpoint with your own customer ID as external_id. A repeated call returns the existing sub-tenant instead of a duplicate. Creation charges that sub-tenant's $199 line immediately; a declined card or no available line blocks creation, so no unbilled or numberless sub-tenant exists.
4. Register each end user. Add the phone numbers that customer's assistant talks to. Only registered numbers can reach the sub-tenant.
5. Send and receive with the sub-tenant key. Send over the WebSocket or POST /api/agent/send-message; replies arrive as message events on that sub-tenant's WebSocket.
6. Meter and offboard. Read month-to-date usage per sub-tenant or in total, raise or lower each message_limit, suspend a customer, or delete the sub-tenant. Delete cancels its line subscription, frees its line, revokes its keys and releases its registered contacts.

POST https://claw-messenger.onrender.com/api/agency/subaccounts
Authorization: Bearer cm_live_<parent key>
Content-Type: application/json

{ "name": "Acme Dental", "external_id": "cust_1042", "message_limit": 1000 }

200 OK
{
  "id": "…",
  "api_key": "cm_live_…",          // shown once; store it for this customer
  "sending_number": "+1XXXXXXXXXX", // this customer's visible number
  "status": "active",
  "message_limit": 1000,
  "external_id": "cust_1042"
}

Your customers never sign up with Claw Messenger. You hold the parent key, and each assistant runs with its own sub-tenant key. Full reference: Agency API docs.

What does “its own number” mean on Claw Messenger?

Every sub-tenant sends from a visible number that no other sub-tenant in your Agency account uses, and that differs from the number self-serve accounts send from. Your customers' end users see a different number for each of your customers.

The number is distinct within your Agency account, not reserved for your company alone. If your product promises each customer a number nobody else uses, choose a provider that sells that, such as Photon's Business lines or Sendblue's per-line plans, and confirm the terms with them.

You do not bring your own number, and you cannot pick an area code today. For how numbers work on every plan, self-serve included, see Claw Messenger phone numbers explained.

What limits should a SaaS plan around?

• New conversations per line: at most 50 first-touch conversations per rolling 24 hours. Contacts who text first do not count, and replies in existing conversations are never blocked. Spread a customer's onboarding over days.
• Daily volume per line: 6,000 messages a day (UTC).
• Monthly cap per sub-tenant: message_limit defaults to 1,000 and you can raise it; messages above 1,000 bill at $0.005.
• One owner per end-user number: a phone number registers to one account at a time. If it is already registered under another account, registration returns 409 Conflict.
• Connections: up to 20 WebSocket connections per sub-tenant, and 100 sub-tenant creations per 10 minutes.
• Conversational use only: Agency lines are for two-way conversations with people who expect them. They are not for cold outreach or mass marketing.

What happens when a line reaches each cap is covered in limits and reliability.

When does another option fit better?

• Apple Messages for Business fits when customers should reach a verified brand from Maps, Safari or Search, and you can register each brand through an Apple-approved provider. Apple allows one commercial account per business, and the business never sees the customer's phone number.
• Sendblue fits when procurement needs SOC 2 or HIPAA; its pricing page lists both on Enterprise.
• Photon fits when shared numbers at $25 a month are enough, or when you want a line of its own per project at $250 a line. See Claw Messenger vs Photon.
• Inkbox fits when each assistant also needs its own mailbox; every identity comes with one. See Claw Messenger vs Inkbox.
• Twilio fits when SMS is enough and you want numbers that sit in each customer's own subaccount.

Claw Messenger fits when you want a working iMessage thread per customer from one API call, a published per-customer price, and RCS and SMS fallback, without running Macs.

Can I prototype before Agency?

Yes. A self-serve plan proves the thread: Base costs $5 a month for 250 messages and Pro costs $50 for 15,000 messages and up to 50 registered contacts. A self-serve account is one workspace sending from a number Claw Messenger assigns, so it does not separate your customers. Use it to confirm one reply reaches your backend, then request Agency. See plans and limits.

iMessage API for SaaS: questions

Related

• Agency overview and pricing
• Agency API reference
• iMessage for multiple client accounts
• Pro vs Agency
• Claw Messenger vs Sendblue
• Apple Messages for Business guide
• iMessage API comparison