Every channel decision is a comparison, so these guides make the comparisons properly: iMessage against SMS, against email, against WhatsApp Business, and the recurring question of whether Twilio can send iMessage at all. Each one states where the other channel genuinely wins, because a channel-mix decision built on a dishonest comparison fails in production, not in the deck.
4 guides
Cold email replied at 0.45% across 7.5 million sends in 2025 and roughly one in eight commercial emails never reached an inbox. A dated-numbers comparison of the two channels across deliverability, reply behavior, and thread persistence, plus the jobs where email still wins outright.
Meta has paused WhatsApp marketing templates to US numbers since April 2025, which settles the US outbound question before reach or reply rates enter it. A concrete comparison: who is on each app, how opt-in actually works on each, and where the channel choice is determined by geography.
The short answer is no: Twilio's messaging channels are SMS, MMS, RCS, and WhatsApp, and no CPaaS sends iMessage. What Twilio offers instead, why Apple Messages for Business is a different product than people expect, and how teams actually send blue bubbles at work.
A dimension-by-dimension comparison of iMessage and SMS for B2B outbound, including the volume crossover where a flat line beats per-segment pricing and a decision rule for picking the right channel per job.