Launch HN: Chert (YC P26) – Twilio for iMessage
Summary
Chert is an iMessage infrastructure API that enables developers to build and deploy AI-powered messaging at scale, positioning itself as 'Twilio for iMessage' with real blue-bubble delivery, read receipts, and webhooks.
Hey HN! We’re Gary and Ian, and we’re building Chert (<a href="https://www.trychert.com/">https://www.trychert.com/</a>), an API for businesses to send, receive, and automate iMessage conversations at scale. Check out our demo: <a href="https://www.youtube.com/watch?v=SRdwvVxMMoI" rel="nofollow">https://www.youtube.com/watch?v=SRdwvVxMMoI</a>.<p>We originally started by building products on top of iMessage because the blue bubble interface, typing indicators, and reactions made agentic conversations feel more human than ones on SMS/RCS. These included a one-shot iMessage agent builder that reached 2,000 users in one week and an automated iMessage outbound sequencer that sent thousands of outbound messages per day.<p>The hard part is that iMessage does not have a native API like SMS/RCS. Sending and receiving iMessages requires a separate infrastructure that is difficult to set up and maintain, especially at scale.<p>As we talked to more companies, we realized that the highest-volume use cases for iMessage were not B2C agents or even sales. They were things like customer service, missed-call text-back, cart abandonment, and inbound lead capture in verticals like home services, DTC brands, and property management that drive the highest volume.<p>Furthermore, these companies often need additional support, such as custom infrastructure setup (e.g. contact card, area code, or local worker sessions), integration support with their existing SMS/RCS or voice agent systems, and a reliable way to scale their volume over time.<p>We built Chert to be an infrastructure layer for businesses to handle iMessage conversations at scale. Businesses can use our API to send and receive iMessages programmatically, route replies to humans or agents, and integrate conversations into the systems they already use.<p>To maintain stability across both outbound and inbound use cases, we built phone line health checks and SMS/RCS fallback systems. We also integrate with existing SMS/RCS systems, voice agents, CRMs such as Salesforce, HubSpot, and Attio, and tools like Slack. Finally, we let businesses reliably scale from a few test lines to hundreds of lines with automated line provisioning and a usage-based pricing structure.<p>We’re working with companies doing conversational messaging in DTC, sports programs, property management, and home services at the scale of hundreds of lines.<p>We’d love to hear your thoughts on this and other similar verticals where iMessage could be useful. All comments welcome!
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# Chert | iMessage Infrastructure for Reaching People at Scale
Source: [https://www.trychert.com/](https://www.trychert.com/)
Backed by
Build and deploy AI on iMessage to reach people at scale while maintainingquality,trust, andpersonalized interaction\.
Hey\! Is the 2BR on Pine still open?
Looking for a Sept 1 move\-in\.
Saturday morning works for me\.
Pine Street · Tour
Sat 10:00 AM · Confirmed
Delivered
Chert
iMessage
Saw the launch, congrats\!
We help GTM teams book meetings via iMessage\.
10x reply rate vs cold email\.
iMessage
First question to your team\.
On it — pulling the numbers now\.
Should have a draft by EOD\.
Perfect\. Free for 15 min next week?
Derrick
kicking off the launch thread
Gary
Heads up, moved you to Tuesday
Sent as SMS
Latest menu, ready to ship?
EXPLORE THE API
\+ many more
Verified phone numbersMessage receiptsWebhooksCompliance audits
0%
average response rate on cold outbound
0%
response rate on warm outbound
<0min
setup via our API and Webhooks
Want a 2 min tour of the dashboard?
Order \#4821 still hasn't shipped
Left the warehouse this morning\. ETA Wednesday\.
Can I move my haircut to Saturday?
Saw your post on scaling the AE team\.
Built something that books meetings on iMessage\.
Salesforce
Attio
GoHighLevel
Slack
Close
Vapi
HubSpot
Chert
FAQ
## Everything you need to know\.
Answers to the questions we hear most\.
Is this real iMessage, or just SMS branded as iMessage?
Real iMessage\. Outbound and inbound flow over Apple’s iMessage protocol with the blue\-bubble UX your customers already trust\. We fall back to SMS only if a recipient isn’t on iMessage, and we surface that distinction in the API so you always know which channel a message landed on\.
How is this different from sending SMS through Twilio?
Twilio is an A2P SMS pipe: carrier\-filtered, 10DLC\-registered, and visibly automated\. Chert delivers a peer\-to\-peer iMessage thread that opens with the blue bubble, supports read receipts and tapbacks, and lives in the same inbox as a recipient’s family and friends\. Open and reply rates are categorically different because the channel is\.
What about deliverability and spam flags?
Because iMessage is end\-to\-end and tied to Apple ID, it doesn’t inherit the carrier\-side filtering that hammers A2P SMS\. We rotate sending identities, warm them gradually, and cap volume per identity per day to stay well below the heuristics Apple uses to throttle abusive senders\. Anyone promising "unlimited blast" volume is one ban away from disappearing\.
How do I connect Chert to the tools my team already uses?
We expose a REST API and webhooks for every inbound and outbound event, so you can wire conversations into your CRM, sales tools, voice agents, or internal data store with a few hours of work\. We also ship native sync for the common cases \(lead created, meeting booked, opt\-out received\)\. If you’d rather not build, we’ll handle the integration during onboarding\.
Let's talk
## Build with *iMessage\.*
20\-minute kickoff\. We'll talk through your use case and work on integrating iMessage into your application\.
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