Senior/Staff Backend Engineer

Senior/Staff Backend Engineer About Blue Blue is building a new mobile platform: an AI-first phone operating system, custom models and custom hardware. True autonomous delegation isn't possible from an app or VM sandbox—it requires owning the entire stack. Blue operates at the OS level, giving our models continuous, system-wide context to proactively triage incoming information, and execute multi-step tasks. Imagine having a chief of staff that can handle all notifications on your behalf and do any task you can conceivably do from your phone, all while maintaining the highest level of security and privacy. Today, Blue runs as a custom operating system on Google Pixel devices while our own dedicated hardware is in development. Our first users already rely on Blue as their primary daily phone, and we ship OS updates daily. We’re a small, seed funded high-velocity team going into a series A. We are now preparing to scale the platform from tens of daily active users to thousands. The role You will own the servers behind every Blue phone: the assistant's backend, messaging, the password vault, iPhone migration, and the infrastructure they run on. You will set the bar for how we review, deploy and operate code. Because we are working on an OS, this role is as much about reliability, security and review, as new features. What you'll own Reliability. Monitoring and alerting, on-call, incident response and postmortems, and tested backups with regular restore drills. Deploys. Repeatable, staged releases with a fast rollback. Data and security. Least-privilege access to production, secrets management, and the systems that hold customers' passwords and personal data. Capacity and limits. Rate limits, payload and token budgets, query costs, and LLM spend per user, worked out, and smoothly balanced with on device models before they cause an outage. Review and mentoring. Reviewing changes from teammates and AI agents, and helping early-career engineers grow into strong ones. Our stack Node.js (Express, WebSockets), PostgreSQL, AWS (RDS, S3, ECS), Google Cloud KMS, Firebase and Twilio. We use LLM APIs from Anthropic, OpenAI and Google, including realtime voice. What we're looking for You have carried a pager for a product with real users. You have been through a launch or a growth spurt, and you know what breaks first. Strong PostgreSQL: schema design, migrations without downtime, query tuning, and locking under concurrency. Security instincts: you treat a password vault and production access with the care they need. You do the arithmetic early: body sizes, token budgets, timeouts, growth. You give real reviews, keep PRs tidy, and have mentored junior engineers. You are comfortable owning infrastructure end to end, from architecture to on-call You work well with ambiguity and can move quickly without sacrificing quality You want to make a Blue Phone your daily phone Nice to have Production experience with LLM APIs: latency, cost, streaming, and evaluating quality. Experience with infrastructure as code and observability tools. OS, Security, or Android development experience. Experience reviewing AI-generated code, or working with coding agents. Why join now You will be the most senior engineer in your domain on a small team, hired to set our standards for running in production. Your work goes straight to customers who rely on their phone every day. Even though we use AI tools for most of our development, we have gone through a lot of effort to ensure that our infra is not AI generated slop, and you get to carry that torch. Logistics Onsite in Santa Clara, CA 160K-240K base salary plus meaningful equity We are also hiring for other engineering roles across ML, backend, security, OS. We only posted our top priority positions, get in touch if you are interested in working with us! #J-18808-Ljbffr