Photon Raises $4.5 Million to Bring AI Agents Into Messaging Apps

Photon has raised $4.5 million to help developers put AI agents inside messaging services people already use, rather than persuade them to download another app. TechCrunch reported the seed financing on October 1. Co-led by Gradient and A*, the round backs a startup claiming substantial developer interest—but whose open-source software still accounts for nearly all its use.

Vercel, HongShan, Z Fellows, Llama Ventures, Karman and angel investors also participated. Photon will use the seed funding to develop its products, which supply the tools for agents to work across conversations rather than operate as standalone mobile apps.

An app-download problem becomes a messaging business

Co-founders Daniel Tian and Ryan Zhu arrived at the idea while building consumer apps as students. Finishing the software was not their only problem: getting people to discover it repeatedly became a bottleneck. An agent inside iMessage offered a different route, reaching users through Apple's existing Messages app.

Tian had built a bot that texted his friends back as him. When the founders released the technology as open source on GitHub, thousands of developers adopted it. Photon now provides infrastructure for other developers' agents, rather than asking consumers to adopt one Photon assistant.

The company made its distribution thesis unusually literal on September 17, holding an “app funeral” in a San Francisco church. The developer event included panels from Vercel, Stripe and OpenAI, along with a coffin for app icons. Tian told TechCrunch that replacing apps would take time, but he believes the shift is inevitable.

The product is less theatrical. Photon packages several tools for building and operating agents across iMessage, WhatsApp, Telegram, SMS or RCS, email and voice. Its offering includes:

• A unified application programming interface, or API, giving developers a common way to connect their software.
• An extensible channel framework for adding messaging interfaces.
• A command-line interface and an observability suite—tools for working with the software and monitoring its operation.

Free adoption and paid operation are different measures

In April, the founders began selling a managed version through subscription tiers. The hosted platform offers 99.95% uptime, according to TechCrunch, and is described as SOC 2 Type II and HIPAA-compliant. That is a different proposition from running the open-source software on a local Mac for a hobby project.

98%Open-source share of use

Photon says its open-source version accounts for 98% of its use. This measures usage, not the share of customers or revenue.

Photon has paying clients, and usage beyond 10 users requires moving from the free tier to one of three paid tiers. Customers named by TechCrunch include Corgi Insurance, social introductions app Boardy, dating platform Ditto, business banking platform Rho, finance assistant Fliptexts and AI email client Slashy.

Its reported growth is fast, but the financial scale remains undisclosed. Photon says more than 40,000 developers have signed up and revenue grew tenfold in four months. It is not sharing revenue figures, so that growth rate does not reveal the size of the subscription business.

Connecting people now, other agents later

Photon's integrations extend beyond individual customers. Nous Research's Hermes agent uses Photon as its default iMessage layer, and Vercel is both an integration partner and an investor. Those relationships put the infrastructure inside other companies' agent products, alongside its direct developer offering.

Tian sees a further opportunity in connecting agents to one another, not just to humans. He described a travel assistant bringing in flight-booking and hotel-booking agents when needed. That is his future vision for Photon; today's business centers on helping agents reach people through existing communication channels.