Sendblue vs Twilio: iMessage API vs SMS API (2026)
Twilio is the dominant SMS API, but it cannot send iMessages. With SMS deliverability declining due to A2P filtering and carrier spam blocking, businesses are adding iMessage via Sendblue. Here's how they compare.
| Feature | Sendblue | Twilio |
|---|---|---|
| iMessage Support | Yes | No |
| SMS Support | Yes | Yes |
| RCS Support | Yes | Yes |
| A2P 10DLC Required | No (for iMessage) | Yes |
| Carrier Spam Filtering | Bypassed (iMessage) | Subject to filtering |
| Response Rate | ~30-45% (iMessage) | ~5-10% (SMS) |
| Contact Card (vCard) API | Yes | No |
| FaceTime Audio | Yes | No |
| Blue Bubbles | Yes | No |
| Read Receipts | Yes | No |
| Rich Media (native) | Yes | MMS with limits |
| SOC 2 | Yes | Yes |
| HIPAA | Yes | Yes |
Why Businesses Add Sendblue to Twilio
Twilio is an excellent SMS/MMS API — but SMS is becoming less effective. Since December 2024, U.S. carriers have blocked 100% of unregistered SMS traffic. Even registered, compliant businesses face declining deliverability, rising costs, and aggressive spam filtering.
iMessages bypass all carrier filtering. They travel through Apple's servers, not carrier networks. There's no A2P 10DLC registration, no carrier spam filters, no short code stigma. Messages arrive as trusted blue bubbles in the recipient's native Messages app.
Most businesses don't replace Twilio with Sendblue — they use both. Sendblue handles iPhone users via iMessage (with higher response rates), while Twilio handles Android users via SMS. This Twilio + Sendblue integration maximizes reach across all devices.
The A2P Problem
Twilio requires A2P 10DLC registration for all business SMS from 10-digit long codes. This involves:
- Registering your brand with The Campaign Registry
- Submitting campaign use cases for carrier approval
- Waiting weeks or months for vetting
- Paying per-message surcharges
- Facing throughput limits even after approval
iMessage through Sendblue requires none of this. You sign up, get API keys, and start sending immediately. There's no carrier approval process, no campaign registration, and no per-message surcharges from carriers.
Response Rate Comparison
The fundamental reason businesses add iMessage to their SMS stack is response rates:
- SMS response rates: 5-10% for most outbound business messages
- iMessage response rates: 30-45% for the same content sent as blue bubbles
This 3-5x improvement comes from three factors: (1) iMessages aren't filtered by carriers, so they actually reach the recipient; (2) blue bubbles signal a personal, trusted conversation rather than marketing; and (3) iMessage supports richer media, read receipts, and tapbacks that create a more engaging experience.
For sales teams, this translates to approximately 50% improvement in demo and meeting show rates when switching from SMS to iMessage outreach.
Using Sendblue and Twilio Together
The optimal setup for most businesses is to use both platforms:
- Sendblue detects whether the recipient has iMessage and sends blue bubble messages to iPhone users
- Twilio handles Android users and any recipients without iMessage via SMS
- A simple routing layer checks iMessage availability via Sendblue's detection API, then routes to the appropriate platform
This gives you the best of both worlds: maximum deliverability across all devices, with the highest possible response rates for the ~60% of U.S. smartphone users who have iPhones.
Read the full Twilio + Sendblue integration guide to get started.
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Get API AccessFrequently Asked Questions
Can Twilio send iMessages?
No. Twilio only supports SMS, MMS, and RCS. Twilio cannot send iMessages (blue bubbles). To send iMessages programmatically, you need an iMessage API provider like Sendblue.
Should I replace Twilio with Sendblue?
Most businesses use both. Sendblue handles iPhone users via iMessage for higher response rates, while Twilio handles Android users via SMS. Sendblue also supports RCS and SMS fallback, so it can serve as a standalone solution if preferred.
Does Sendblue require A2P 10DLC registration?
No. iMessages sent through Sendblue bypass carrier networks entirely, so there is no A2P 10DLC registration required. This eliminates weeks of registration time and ongoing compliance overhead.
What are the response rate differences?
Businesses typically see 30-45% response rates with iMessage compared to 5-10% with SMS. This 3-5x improvement is due to iMessages bypassing spam filters, appearing as trusted blue bubbles, and supporting richer media.