If you have ever built anything that sends a text, you have probably used Twilio. It is the default, it is excellent at what it does, and it cannot send an iMessage. Not as a missing feature — as a structural impossibility.
Why not
Twilio is a communications platform built on carrier infrastructure. It sends SMS, MMS and RCS by connecting to the phone network, which is a regulated system with formal interconnect agreements.
iMessage does not travel over that network at all. It goes over the internet to Apple's servers, between devices tied to Apple IDs, end-to-end encrypted. There is no carrier interconnect to buy, because Apple is not a carrier and has never sold access — the full explanation is here.
So Twilio cannot add iMessage support the way it added RCS. There is nothing to integrate with.
What each one is for
| Twilio | iMessage API | |
|---|---|---|
| Channels | SMS, MMS, RCS, voice, WhatsApp, email | iMessage, usually with SMS/RCS fallback |
| Reaches Android | Yes | Only via fallback |
| Bubble colour on iPhone | Green | Blue |
| Pricing | Per message segment | Per phone line, flat |
| 10DLC registration | Required | Not required for iMessage |
| Time to first message | Days to weeks | Same day |
| Delivery guarantees | Formal, contractual | Best effort |
| Platform sanctioned | Yes | No |
When Twilio is right
- Anything that must arrive. Security codes, outage notices, regulatory notifications. Twilio has decades of formal delivery guarantees; iMessage providers do not.
- Your list is Android-heavy. You would be paying for a channel that reaches a minority.
- Very high volume, low value per message. Metered pricing wins at scale.
- You need voice too. Nobody in the iMessage category competes on that.
When an iMessage API is right
- The message needs to be believed. A green bubble from an unsaved number is judged before it is read — that is the whole argument.
- Photos matter. MMS compression makes your work look worse; iMessage carries full quality.
- You want a conversation. Read receipts, typing indicators and tapbacks change the reply rate.
- You need to launch this week. No 10DLC registration to wait on.
Running both
Plenty of businesses do, and it is a reasonable architecture: transactional and must-arrive traffic through Twilio, relationship and conversational traffic through an iMessage line.
The cost is operational — two vendors, two sets of copy, two reporting surfaces, and a suppression list that must stay synchronised across both. If that sounds like more than you can maintain, pick a provider with built-in fallback instead and run one system. Sendblue handles RCS and SMS automatically; the full comparison covers who else does.
The suppression trap
If you run two vendors, an opt-out honoured in one and not the other means you will message someone who told you to stop. That is the single most common compliance failure in multi-vendor messaging, and it is entirely an integration problem — see connecting iMessage to your CRM.