Founding Backend Engineer

About the Role Build and operate the backend for an AI assistant that communicates through text, email, and phone. As a hands-on founding engineer, you will own systems where reliable, timely message delivery is essential and help shape the team's engineering standards. What You'll Do Design and operate messaging pipelines for inbound and outbound communications, with reliable ordering, retries, and delivery tracking. Build the background agent runtime, including concurrency controls, timeouts, cancellation, and recovery from model or tool failures. Develop scheduling systems for future actions that must run reliably and in the correct time zone. Plan capacity, load-test services, optimize databases, and make architectural improvements to support growth. Own security and privacy practices, including credential encryption, Postgres schemas and migrations, and data deletion workflows. Build observability and cost tracking that traces messages through downstream model and tool calls. Set backend engineering standards and help recruit and mentor a growing engineering team while remaining hands-on. What We're Looking For At least 4 years of software engineering experience, including substantial production on-call responsibility. Deep distributed systems experience with queues, workers, retries, idempotency, and production failure modes. Experience scaling production systems through rapid growth and making sound tradeoffs about what to address immediately. Production experience with Postgres, including schema design, migrations, and performance tuning, as well as cloud infrastructure and infrastructure as code. Experience shipping production systems in TypeScript or Python. Background in messaging, telephony, or event-driven systems where dropped or duplicated events have real costs. Experience with observability, distributed tracing, capacity planning, and measuring latency and cost. Hands-on technical leadership and familiarity with AI-assisted development workflows, including verifying and owning generated code. Compensation & Benefits Base salary: $200,000 to $300,000 annually. Visa sponsorship is not available. Location Full-time, on-site in San Francisco, California.