The most affordable dedicated iMessage API: $49/month

What is the ZeroSettle iMessage API?

ZeroSettle gives your business its own phone number on real iMessage, running on Apple hardware we operate in a server facility. The number is used only for iMessage. Your code sends from it with POST /api/imessage/send and hears every reply on a signed webhook, so customers on iPhone see blue bubbles, your brand name and photo, typing indicators and tapbacks. For background, see what an iMessage API is.

How much does the ZeroSettle iMessage API cost?

Pro costs $49/month for one dedicated number and Growth costs $599/month for three. Both are billed monthly by Stripe with a 30-day money-back guarantee: ask within 30 days and you are refunded in full and the subscription is cancelled.

Pro is $49/month flat, no per-message fees on API texts. Credits pay for the hosted AI agent, one per text it sends; texts your own server sends through the API never use any. Packs are 1,000 for $50 or 5,000 for $200, paid once, and never expire. The money-back guarantee covers the subscription, not packs. More on plans in ZeroSettle pricing.

How does $49/month compare with other iMessage APIs?

ZeroSettle Pro is $49/month for a dedicated iMessage number that can message first. No managed iMessage API we checked publishes a lower price for a dedicated number (checked October 25, 2026). Courio also lists $49 (Starter: 500 outbound/month, then $0.02/message). Cheaper offers exist, but they are shared numbers or run on hardware you supply.

Prices are each vendor's own published figures in US dollars. Sendara's figures come from its own guide page; myCRMSIM's pricing page could not be read, so its figure comes from press reports. More detail is in iMessage API pricing compared and the most affordable dedicated iMessage API.

The $49 price does not come with a larger allowance. Pro opens 5 new contacts a day per number, fewer than the 30–50 most $99+ plans allow; people who text first are never limited. If you need more first messages a day, Growth or a 30–50-a-day plan fits better; if you need SMS fallback for Android, Sendblue, Linq or LoopMessage offer it.

What are the limits?

The limits keep a number out of Apple's spam filters, and the API enforces them for every caller, the console included.

• New contacts: 5 a day per number on Pro, 50 a day (and 3 per 15 minutes) on Growth, reset at 3 AM Eastern. Over the limit, a send returns 429 new_contact_limit.
• Known contacts: anyone who texted first, and every ongoing conversation, share the number's 10,000 messages a day.
• Unanswered messages: at most 2 to a contact who has never replied; a third returns 403 awaiting_reply.
• Attachments wait for a reply: photos, voice messages and polls go only to contacts who have replied at least once (403 attachment_before_reply).
• iMessage only: no SMS or email fallback; 422 not_on_imessage means nothing was sent.
• STOP: a contact who texts STOP is blocked on every number on the account (403 recipient_opted_out).
• One send at a time per number: a send that waits about 12 seconds returns 429 line_busy; retry after 2 seconds.

Every error code is in Errors, limits, and compliance.

What do a send and a webhook look like?

A send is one HTTPS POST with a bearer token (Send a message). It returns once the number has handed the message to Apple, normally in 2–5 seconds.

curl -s -X POST -H "Authorization: Bearer $TOKEN" -H 'Content-Type: application/json' \
  -d '{"to":"+18055559876","text":"Hi from the line"}' https://portal.zerosettle.io/api/imessage/send

A reply reaches your webhook as compact JSON with sorted keys, signed in the X-ZeroSettle-Signature header:

POST https://abc123.trycloudflare.com/webhook
Content-Type: application/json
User-Agent: ZeroSettle-iMessage/1
X-ZeroSettle-Event: message.received
X-ZeroSettle-Signature: t=1757400012,v1=3f0c…(64 hex chars)

{"event":"message.received","message":{"direction":"in","guid":"5A6F…","handle":"+18055559876","id":44,"status":"received","text":"hey!","ts_ms":1757400012000}}

The signature is HMAC-SHA256 with your webhook secret over "<t>." + raw body. Verify the raw bytes before parsing and reject a t more than 300 seconds from now (Webhooks, step by step):

import hmac, hashlib, time

def verify(secret: str, header: str, raw_body: bytes, tolerance: int = 300) -> bool:
    try:
        parts = dict(p.split("=", 1) for p in header.split(","))
        t, v1 = int(parts["t"]), parts["v1"]
    except Exception:
        return False
    if abs(time.time() - t) > tolerance:
        return False
    expected = hmac.new(secret.encode(), f"{t}.".encode() + raw_body, hashlib.sha256).hexdigest()
    return hmac.compare_digest(expected, v1)

Answer 2xx within 10 seconds; otherwise ZeroSettle retries 3 more times, after 1, 5 and 20 seconds. React only to message.received in an auto-responder, because your own sends come back as message.sent. How to receive iMessages with a webhook covers retries and dedupe, and how to send an iMessage from code without a Mac covers the errors.

What can a ZeroSettle number send and receive?

Beyond text, a number handles most of what people use in Messages:

• Photos with captions and voice messages, both ways (Attachments).
• Tapbacks and typing indicators, both ways (Typing indicators).
• Inline replies, 13 iMessage effects and polls (Send a message).
• Chat backgrounds on iOS 26, received as a background.changed event.
• Your brand name and photo, shared with each conversation.
• Several numbers working as one behind one API key and webhook (Your iMessage number).
• Group chats of up to 31 people, enabled per number on request (Group chats).
• Sign in with iMessage: verify a user by the iMessage they send (Sign in with iMessage).

Can an AI agent set it up or answer texts?

Yes, both. ZeroSettle runs a remote MCP server at https://portal.zerosettle.io/mcp, speaking Streamable HTTP with OAuth 2.1 (dynamic client registration and PKCE). Connected to Claude, Cursor or any MCP client, the agent can sign you up, set your name and photo, mint an API key, register and test your webhook, and send a test message to your own number. It is a setup tool: the server you build owns the conversation with your customers. See Connect your AI agent, MCP and connecting Claude Code or Cursor to an iMessage number.

With no server at all, the hosted AI agent answers your number for you from the business context you write, using one credit per text it sends (AI agent).

Where is the full API reference?

The docs are at portal.zerosettle.io/docs, and agents can read the raw markdown at https://portal.zerosettle.io/docs.md. Each page has its own URL:

1. Your iMessage number: plans, getting a number, and more than one number
2. Authentication: bearer tokens and what 401, 402 and 403 mean
3. Quick start for an agent: the whole API in a few curl calls
4. Send a message: texts, inline replies, effects, polls, and your name and photo
5. Attachments: photos and voice messages, both ways
6. Read messages: conversations and message history
7. Typing indicators: show and receive “…”
8. Retention offers: a worked use case
9. Customer support: a worked use case
10. Sign in with iMessage: verify a user by the iMessage they send
11. AI agent: your own model, or the hosted agent with no server
12. Webhooks, step by step: events, signing, retries
13. Live stream (SSE): watch a number in real time
14. Connect your AI agent: Claude, Cursor or any MCP client
15. MCP: every tool the connector exposes
16. Errors, limits, and compliance: every error code and limit
17. CRM integrations: log conversations in your CRM
18. Group chats: groups of up to 31 people, enabled per number on request
19. Switch from Photon: a migration guide
20. Switch from Linq: a migration guide
21. Switch from Sendblue: a migration guide

How do I get a number?

1. Open Get started and sign in with your phone number (you get a one-time SMS code).
2. Answer one question about what you will use the number for. That claims the number.
3. Set your brand name and photo, and text your own phone a test message from the new number.
4. Subscribe. The console and the API open once the subscription is active.

Numbers can sell out; when they do, there is a waitlist. Growth customers sign up from a Growth link instead.

How we checked

We checked everything on this page on October 25, 2026.

• ZeroSettle facts come from its API docs, and we confirmed that each docs page linked above loads.
• Competitor prices come from each vendor's own pricing page. Courio's page renders in the browser, so we read its prices from the site's own script; Sendara's come from its own guide because its pricing page did not load; myCRMSIM's come from press reports. We tested no competitor accounts.

Prices change often. We log changes to this page in the changelog.