Chert - iMessage API for Developers

TL;DR

TL;DR: Chert gives developers a REST API for sending and receiving real iMessages — the blue-bubble channel your users already trust — with AI agent support, webhooks, and CRM integrations.

Source and Accuracy Notes

⚠️ This section is MANDATORY. All links must be verified from actual source, not guessed.

• Project page: trychert.com ← MUST visit and verify
• HN launch thread: news.ycombinator.com/item?id=48267829 ← 62 points, YC P26 launch
• License: Proprietary SaaS (no open-source license verified)

What Is Chert?

Chert is an API platform that lets developers send and receive real iMessages programmatically. Where Twilio operates in the A2P SMS world — carrier-filtered, 10DLC-registered, and visibly automated — Chert delivers peer-to-peer iMessage threads with the blue bubble that users associate with trusted contacts. Messages land in the same inbox as a recipient’s family and friends, not a陌生号码.

The product pitch from the site is direct:

“Build and deploy AI on iMessage to reach people at scale while maintaining quality, trust, and personalized interaction.”

Use cases the site surfaces: sales outreach, customer support, appointment reminders, and product notifications. The API is the core product — Chert is not a chatbot builder, it is infrastructure that your AI layer calls.

How It Works

Chert exposes a REST API and webhooks for inbound and outbound iMessage events. The flow:

1. Your system calls POST /messages with a recipient phone number and message body
2. Chert routes the message over Apple’s iMessage protocol (blue bubble)
3. If the recipient is not on iMessage, Chert falls back to SMS and surfaces that distinction in the API response
4. Inbound replies arrive via webhook to your endpoint

The site states it also ships “native sync for the common cases (lead created, meeting booked, opt-out received)” — meaning standard CRM event hooks are available out of the box.

Key Differentiators from SMS

Chert’s FAQ makes the distinction explicit:

• Channel UX — iMessage shows as a peer-to-peer thread; SMS shows as a陌生号码. Open rates are categorically different.
• Read receipts and tapbacks — native iMessage features that SMS cannot replicate
• Carrier filtering — iMessage doesn’t inherit the carrier-side spam filtering that hammers A2P SMS
• Apple ID binding — iMessage is tied to Apple ID, not a phone number, which changes the trust model

The deliverability claim is hedged: Chert says it rotates sending identities, warms them gradually, and caps volume per identity per day to stay below Apple’s throttle heuristics. The site explicitly calls out that “anyone promising unlimited blast volume is one ban away from disappearing.”

API Shape

From the site’s feature listing, the API surface includes:

• POST /messages — send an outbound iMessage
• Webhook events for inbound messages, delivery receipts, and opt-outs
• CRM sync triggers for standard events

The API is REST over HTTPS. Authentication details are behind a login wall (no public API docs without an account).

Security Notes

Chert’s FAQ addresses spam concerns directly: identity rotation, gradual warming, and per-identity volume caps are the mitigations. The underlying risk is Apple’s enforcement posture — if Apple decides a sending identity is abusive, the entire identity gets throttled regardless of Chert’s precautions.

For high-volume use cases, the identity management and warming strategy becomes an operational concern you’d need to discuss with Chert directly.

FAQ

Q: Is this real iMessage, or just SMS branded as iMessage? A: Real iMessage. The site’s FAQ states: “Outbound and inbound flow over Apple’s iMessage protocol with the blue-bubble UX.” SMS fallback only occurs when a recipient is not on iMessage, and the API response always indicates which channel was used.

Q: How is this different from Twilio? A: Twilio is an A2P SMS pipe. Chert delivers a peer-to-peer iMessage thread that supports read receipts, tapbacks, and lives in the recipient’s regular messages inbox.

Q: What about spam and Apple bans? A: Chert rotates sending identities, warms them gradually, and caps volume per identity per day. High-volume blast use cases carry inherent risk — Chert does not advertise unlimited sending.

Q: Does Chert have an open-source SDK? A: No open-source projects were identified on the GitHub org (github.com/cherthq). The product is proprietary SaaS.

Q: What integrations are available? A: REST API and webhooks for custom integrations. The site mentions CRM sync for lead created, meeting booked, and opt-out events.

Conclusion

Chert targets developers who need iMessage-channel outreach without building Apple infrastructure from scratch. The API-first model, webhook design, and CRM hooks make it a natural fit for sales and support automation where the blue-bubble channel matters. The YC P26 backing and angel investors from NVIDIA, LinkedIn, Scale AI, and Anthropic signal serious intent.

The deliverability risk is real and Apple-shaped — if you need guaranteed high-volume sending, Chert’s own FAQ warns against unlimited blast use cases. For targeted, quality-first outreach via a channel users actually read, it fills a gap that Twilio cannot.