Senior Backend Engineer

About the job

We are looking for a senior backend engineer to build and operate the core AI/ML-backed systems that power large-scale, consumer-facing products. You will work on production-grade AI runtimes, retrieval systems, and ML-adjacent backend infrastructure, making pragmatic tradeoffs across quality, latency, reliability, and cost. We are hiring applied AI engineers, not engineering-for-ML profiles. This role is not an entry point into AI/ML. You are expected to already have hands-on experience shipping ML-backed backend systems in production. Responsibilities: • Own and deliver end-to-end backend systems for AI product runtime, including orchestration, request lifecycle management, state/session handling, and policy enforcement. • Design and implement retrieval and memory primitives, end-to-end document ingestion, chunking strategies, embeddings generation, indexing, vector/hybrid search, re-ranking, caching, freshness, and deletion semantics. • Productionize ML workflows and interfaces, including feature and metadata services, online/offline parity, model integration contracts, and evaluation instrumentation. • Drive performance, reliability, and cost optimization, owning P50/P95 latency, throughput, cache hit rates, token and inference costs, and infrastructure efficiency. • Build observability by default, including structured logs, metrics, distributed tracing, guardrail signals, failure taxonomies, and reliable fallback paths. • Collaborate closely with Applied ML teams on model routing, prompt and tool schemas, evaluation datasets, and release safety gates. • Write clean, testable, and maintainable backend code, contributing to design reviews, code reviews, and operational best practices. • Take systems from design, build, deploy, and operate, including on-call ownership and incident response. • Continuously identify bottlenecks and failure modes in AI-backed systems and proactively improve system robustness.

Requirements

• Backend Development
• Machine Learning
• APIs

Qualifications

• Bachelor's degree in computer science, engineering, or a related field

Preferred Technologies

• Backend Development
• Machine Learning
• APIs

About the company

Proximity Labs specializes in building AI/ML-backed systems for consumer-facing products.