Launch HN: Chert (YC P26) – Twilio for iMessage

The Blue Bubble Revolution: How Chert Is Building the “Twilio for iMessage”

In a world where SMS feels transactional and RCS struggles for adoption, iMessage stands apart—not just as a messaging protocol, but as a cultural phenomenon. The blue bubble is more than a color; it’s a signal of trust, immediacy, and human connection. Now, a new startup called Chert is aiming to unlock that power for businesses at scale, effectively building what many are calling the “Twilio for iMessage.” Founded by Gary and Ian and backed by Y Combinator’s P26 batch, Chert is tackling a surprisingly overlooked gap in enterprise communication: the lack of a native, scalable API for iMessage.

Unlike SMS or RCS, iMessage doesn’t offer a straightforward developer interface. Sending and receiving messages requires complex infrastructure, often involving physical Apple devices, SIM cards, and custom routing logic. For startups and enterprises alike, this has made iMessage automation a technical minefield—until now. Chert’s platform allows businesses to programmatically send, receive, and automate iMessage conversations, routing replies to human agents or AI systems, and integrating seamlessly with existing tools like Salesforce, Slack, and HubSpot.

The iMessage Advantage: Why Blue Bubbles Beat Green

The appeal of iMessage isn’t just technical—it’s psychological. When a customer receives a message in a blue bubble, they perceive it as more personal, secure, and trustworthy than a green SMS. This perception translates into real business outcomes. Chert’s founders discovered early on that agentic conversations—those powered by AI or human agents—felt significantly more “human” when conducted over iMessage, thanks to features like typing indicators, read receipts, and message reactions.

These subtle cues mimic real-time conversation in a way that SMS never could. Imagine a customer service rep typing a response and the customer seeing “… is typing”—it creates a sense of presence and responsiveness that static SMS lacks. In one of Chert’s early experiments, a one-shot iMessage agent builder gained 2,000 users in just one week, demonstrating the hunger for more natural, conversational interfaces.

Moreover, iMessage is deeply embedded in the iOS ecosystem. Over 90% of smartphones in the U.S. run iOS, and Apple users are typically higher-income, more engaged, and more likely to respond to branded messages. For verticals like DTC brands, property management, and home services, this audience alignment is invaluable.

The Hidden Challenge: No Native API

Despite its popularity, iMessage has a fundamental flaw for developers: no public API. Unlike Twilio for SMS or Google’s RCS APIs, Apple has never opened iMessage to third-party developers in a scalable way. This means businesses wanting to send iMessages must either jailbreak devices, use unofficial workarounds, or build complex internal systems involving real iPhones, SIM cards, and custom routing.

Chert’s founders encountered this firsthand while building their earlier iMessage-based tools. They built an automated outbound sequencer that sent thousands of messages daily—but maintaining the infrastructure was a nightmare. Device failures, carrier throttling, and Apple’s strict ecosystem controls made reliability a constant challenge.

This led them to a pivotal realization: the real opportunity wasn’t in building another iMessage app, but in solving the infrastructure problem itself. They pivoted to Chert, a platform that abstracts away the complexity of iMessage, offering a clean REST API that behaves like Twilio—but for blue bubbles.

Real-World Use Cases: Where iMessage Shines

While B2C AI agents and sales outreach were early experiments, Chert’s founders discovered that the highest-volume, highest-impact use cases were in customer service, lead capture, and operational messaging. These aren’t flashy applications, but they’re where iMessage delivers outsized ROI.

Take home services, for example. A plumbing company can use Chert to send automated iMessages to customers after a missed call: “Hi Sarah, we saw you called about a leak. We’re available now—reply to book a slot.” The message appears in a blue bubble, feels personal, and includes a clear call to action. Because it’s iMessage, the customer is more likely to respond—and faster.

In property management, landlords use Chert to automate rent reminders, maintenance updates, and lease renewals. A tenant receives: “Hi Alex, your rent is due tomorrow. Tap here to pay online.” The message includes a link, a reaction option (👍), and even a typing indicator if a human agent steps in. This reduces friction and increases payment rates.

DTC brands are using Chert for cart abandonment flows. Instead of a generic email, a customer gets: “Your cart is waiting! Complete your order in 2 taps.” The message feels like a friend reminding them, not a bot. Early tests show up to 3x higher conversion rates compared to email.

Building for Scale: Infrastructure That Doesn’t Break

One of Chert’s most impressive technical feats is its ability to scale reliably. Sending iMessages at scale isn’t just about volume—it’s about maintaining Apple’s strict ecosystem rules. Too many messages from one line? Apple might flag it as spam. Device offline? Messages queue up or fail.

To solve this, Chert built a phone line health monitoring system that continuously checks device status, carrier performance, and message delivery rates. If a line goes down, the system automatically reroutes traffic to healthy lines. If iMessage fails entirely, Chert falls back to SMS or RCS—ensuring no message is lost.

The platform also supports local presence, allowing businesses to use area codes that match their customers’ regions. A home services company in Austin can use 512 numbers, making messages feel local and increasing answer rates. This is especially powerful for lead capture, where a “local” number can double response rates.

Integration is another key strength. Chert connects with Salesforce for CRM logging, HubSpot for marketing automation, and Slack for team alerts. A property manager can receive a tenant’s iMessage in Slack, respond directly, and have the conversation logged in Salesforce—all without leaving their workflow.

The Future of Conversational Commerce

Chert’s emergence signals a broader shift in how businesses think about messaging. The era of one-way SMS blasts is fading. Customers now expect conversational, two-way interactions that feel human, even when powered by automation.

As AI agents become more sophisticated, platforms like Chert will enable seamless handoffs between bots and humans. A customer starts with an AI chatbot via iMessage, then escalates to a live agent—without switching channels. The conversation history, context, and sentiment are preserved, creating a smooth experience.

Looking ahead, Chert could become the backbone for agentic commerce—where AI agents not only respond to messages but proactively engage customers based on behavior. Imagine a DTC brand’s AI agent noticing a customer browsing winter coats, then sending a personalized iMessage: “Saw you checking out our parkas. They’re 20% off today—want to try one on?”

This level of personalization, delivered through the most trusted messaging channel in North America, could redefine customer engagement.

Challenges and Ethical Considerations

Of course, with great power comes great responsibility. Automating iMessage at scale raises questions about spam, consent, and privacy. Apple has historically been protective of its ecosystem, and any misuse could lead to platform restrictions.

Chert addresses this with strict compliance protocols: opt-in requirements, message rate limiting, and transparent sender identification. Businesses must verify ownership of phone lines and adhere to carrier guidelines. The platform also logs all messages for auditability.

There’s also the risk of over-automation. If every business starts sending iMessages, the channel could lose its “special” feel. Chert’s founders are aware of this and emphasize intentional use—reserving iMessage for high-value, high-trust interactions.

Still, the potential is enormous. As RCS adoption lags and SMS feels increasingly outdated, iMessage remains a golden opportunity for businesses that want to stand out.

Final Thoughts: The Blue Bubble Era Is Here

Chert isn’t just building an API—it’s enabling a new era of conversational business. By making iMessage accessible, scalable, and reliable, they’re giving companies a powerful tool to connect with customers in a more human way.

From plumbers to property managers, from DTC brands to sports programs, the demand is clear. The blue bubble isn’t just a design choice—it’s a competitive advantage. And with Chert, that advantage is finally within reach.

As Gary and Ian put it: “We’re not just sending messages. We’re building the infrastructure for the future of customer conversation.” In a world of noisy inboxes and ignored emails, that future might just be a blue bubble away.

This article was curated from Launch HN: Chert (YC P26) – Twilio for iMessage via Hacker News (Top)