Founding Engineer
Hybrid (San Francisco, CA)$140k - $250k + equityFull-timePosted 3mo ago
About the role
Founding Engineer at AgentPhone, a YC-backed startup building telephony infrastructure for AI agents. You’ll be the first engineering hire, shipping product, owning infrastructure end-to-end, and directly engaging with customers.
Responsibilities
- Build and scale core telephony infrastructure: SIP trunking, real-time voice (LiveKit), call routing, and media handling
- Own messaging delivery across SMS, iMessage, and RCS, including deliverability debugging when carriers silently drop traffic
- Ship developer-facing surfaces: our API, SDKs, MCP server, webhooks, and dashboard
- Build compliance infrastructure (A2P 10DLC, TCR registration, KYC) so customers don't have to think about it
- Talk to customers directly and turn their problems into features, sometimes the same day
- Set the engineering foundations (testing, CI/CD, observability, on-call) that every future hire inherits
Qualifications
- Experience: Any (new grads ok)
- No telephony experience required; willingness to learn and ship fast
- Ability to use AI tools effectively and move fast in ambiguity
- Shipped real software that people actually use
Skills
Required:PythonTypeScript
Benefits
- Will sponsor visa
Last updated Oct 25, 2026. Interested? Apply on the company site.
About AgentPhone
Phone Numbers for AI Agents
The $2T global telecom industry was built for humans. Agents can't act in the real world today because without a phone number, they lack identity. AgentPhone gives every AI agent its own phone number to reach people and businesses through messages and calls.