Sendblue vs Sinch: iMessage API vs Messaging Super-Network (2026)

Why Businesses Add Sendblue to Sinch

Sinch is a messaging giant. Through acquisitions of companies like SAP Digital Interconnect, Wavy, and MessageMedia, Sinch has built one of the world's largest messaging super-networks. They handle SMS, RCS, WhatsApp, voice, and email at massive scale for enterprises worldwide.

But despite this enormous scale, Sinch has the same limitation as every other CPaaS provider: it cannot send iMessages. This is a significant gap in the U.S. market, where approximately 60% of smartphone users have iPhones.

Sendblue is the dedicated iMessage API that fills this gap. By adding Sendblue to your Sinch stack, you unlock blue bubble messaging to iPhone users with read receipts, typing indicators, and 3-5x higher response rates than SMS.

RCS vs iMessage: Different Protocols, Different Audiences

Sinch is one of the leading RCS providers. But it's important to understand that RCS and iMessage serve entirely different audiences:

• RCS: A carrier-based messaging protocol primarily for Android users. Requires carrier support and is not universally available.
• iMessage: Apple's proprietary messaging protocol for iPhone, iPad, and Mac users. Works on all Apple devices without carrier involvement.

In the U.S., where ~60% of smartphone users have iPhones, iMessage is the dominant rich messaging channel. Sinch's RCS support covers Android users well, but iPhone users still receive green bubble SMS from Sinch, subject to carrier filtering and lower engagement.

Sendblue supports both iMessage and RCS, making it possible to deliver rich messaging to users on both platforms from a single API.

Sinch's Strengths vs Sendblue's Strengths

Where Sinch Excels

• Global scale: One of the largest messaging networks processing billions of messages
• Omnichannel: SMS, RCS, WhatsApp, Facebook Messenger, voice, and email
• RCS leadership: Among the top RCS Business Messaging providers globally
• Enterprise relationships: Direct carrier connections and enterprise-grade SLAs
• Conversation API: Unified API across multiple messaging channels

Where Sendblue Excels

• iMessage API: The only dedicated iMessage API for businesses
• Blue bubble delivery: Messages appear as personal, trusted conversations
• Read receipts and typing indicators: Real-time engagement signals via webhooks
• No A2P registration: Start sending immediately with no carrier approval
• RCS + SMS fallback: Automatic fallback for non-iMessage recipients
• SOC 2 Type II and HIPAA: Enterprise security with BAA available

Using Sendblue and Sinch Together

For enterprises with global omnichannel needs, the optimal approach is to use both platforms:

• Sendblue handles iMessage delivery to iPhone users in the U.S. for maximum engagement
• Sinch handles SMS, RCS, WhatsApp, and voice for Android users and global reach
• Sendblue's iMessage detection API enables intelligent routing: check if a number supports iMessage, then route to the highest-engagement channel available

This gives you Sinch's global messaging super-network combined with Sendblue's high-engagement iMessage channel for the U.S. iPhone audience. Explore Sendblue integrations to see how it fits your communication architecture.