Photon raises $4.5M to expand its messaging-agent platform

The funding will help Photon push its hosted platform for agents that run on messaging channels instead of mobile apps.

Photon, a startup that lets developers build AI agents that run over messaging channels like iMessage and WhatsApp instead of traditional mobile apps, has raised a $4.5 million seed round to expand its managed platform. The round was led by Gradient and A*, with additional investors including Vercel, HongShan, Z Fellows, Llama Ventures, Karman and several angels. Photon started as an open-source iMessage bot project that still represents the majority of its usage, but in April the team launched a hosted, subscription-based service with 99.95% uptime and compliance certifications such as SOC 2 Type II and HIPAA. The company says it has attracted more than 40,000 developers, multiplied its revenue tenfold in four months, kept churn under 3%, and increased messaging volume fivefold in the last month. Its tooling — including a unified API, channel framework, CLI and observability — underpins agents for customers like Corgi Insurance, Rho and Ditto, and is integrated by partners such as Vercel, Nous Research, Tencent’s QClaw and NanoClaw, as well as frameworks like LangChain and infrastructure providers like Render and Railway.