[Remote] Staff Backend Engineer (AI Native), Family AI Lab

Note: The job is a remote job and is open to candidates in USA. Life360 is a company dedicated to keeping families connected through innovative technology solutions. The Staff Backend Engineer will own the inference pipeline and ensure seamless integration of deterministic backend systems with probabilistic AI models, focusing on performance, cost, and data safety.ResponsibilitiesArchitect the inference pipeline that turns Life360 into a context layer LLMs can reason over: soul files, family context, behavioral signals, document understandingChoose models. Choose hosting. Decide what is self-hosted, API-based, fine-tuned, or prompt-engineered. Revisit those decisions as the landscape changesBuild the serving infrastructure. Latency budgets, batching, caching, fallbacks, graceful degradation. Make it run at scale before scale gets hereBuild the eval loop. Know whether changes make the product better or worse, not just whether the demo works. This is the difference between a real product and a magic trickOwn the cost model. Track spend per user, per feature, per family. Find the levers (context compression, model routing, pre-computation) that keep unit economics working from a test group to millionsDefine what gets persisted, what gets summarized, and what gets thrown away. The architecture decision of "what does our data look like to an LLM" lives with youSet the bar for safety, privacy, and trust at the infrastructure layer. Sensitive categories filtered before they propagate. Encryption, access controls, audit trails built in, not bolted onSkillsDeep engineering experience, with significant time spent building and running AI systems in production at meaningful scale. Real users, real load, real on-callFluent in modern LLM serving (vLLM, TGI, SGLang, hosted APIs — whatever's right for the job). No religion about itYou think in evals. You've built harnesses. You know the difference between vibes-based iteration and real progress because you've felt the pain of not having oneYou can build a cloud system from the ground up. Pick the services, wire them together, make them reliable, keep the bill in checkStrong opinions about cost. You've seen inference bills run out of control and have instincts for where the leaks come fromAI-native in your daily workflow. Hands-on with Claude Code, Cursor, or equivalent. You think natively in agentic workflows, prompt engineering, context window management, MCP / function callingComfortable deciding with incomplete information. The spec will be a moving target. You don't need it to settle before you start buildingStrong written communication. You write specs, decision records, and playbooks that an agent (and a human) can act on preciselyExperience with agent systems, retrieval pipelines, or long-context personalizationPrivacy architecture experience in multi-user systems where context is shared across people with different rights to see itYou've built something where the data itself was the moat — and you understand why that's different from building on public dataBenefitsCompetitive pay and benefits.Medical, dental, vision, life and disability insurance plans (100% paid for US employees). We offer supplemental plans for medical and dental for Canadian employees.401(k) plan with company matching program in the US and RRSP with DPSP plan for Canadian employees.Employee Assistance Program (EAP) for mental wellness.Flexible PTO and 12 company wide days off throughout the year.Learning & Development programs.Equipment, tools, and reimbursement support for a productive remote environment.Free Life360 Platinum Membership for your preferred circle.Company OverviewLife360 creates a mobile app for families that helps families feel closer together. It was founded in 2008, and is headquartered in San Francisco, California, USA, with a workforce of 501-1000 employees. Its website is http://www.life360.com.Company H1B SponsorshipLife360 has a track record of offering H1B sponsorships, with 4 in 2026, 15 in 2025, 22 in 2024, 17 in 2023, 21 in 2022, 17 in 2021, 7 in 2020. Please note that this does not guarantee sponsorship for this specific role.