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.