We are seeking a Backend AI Platform Engineer to design and build core backend services that power our Agentic AI Platform, enabling reasoning-driven agents, multi-agent orchestration, dialog management, and outcome-based workflows.You will work closely with the Principal AI Agentic Architect to implement high-performance APIs, orchestration runtimes, agent lifecycle management, and integration with frameworks like LangChain, LangGraph, and LangSmith. This role is hands-on and ideal for someone passionate about building robust, scalable backend systems in a fast-paced, startup-like environment. Key Responsibilities: Platform Backend DevelopmentExperience building agent runtime systems, orchestration layers, or reasoning engines. Implement agent runtime orchestration services for reasoning, planning, and tool invocation (integrating LangChain/LangGraph). Develop APIs and SDKs for building, deploying, and managing agent workflows and tools. Build stateful dialog management and memory services to support multi-turn, context-aware agents. Implement multi-agent communication (A2A) protocols and shared context for collaborative agent behavior. System Architecture & ScalabilityWork with the Architect to build cloud-native, event-driven backend services using microservices or service mesh architecture.Design task scheduling and workflow orchestration (e.g., Temporal/Airflow) for agent planning and long-running operations.Develop real-time message buses (Kafka/Pub-Sub) for agent communication and event propagation.Optimize LLM orchestration performance and cost efficiency with caching, batching, and token usage monitoring. Integrations & Data ServicesImplement integrations with enterprise systems, APIs, and knowledge sources (REST, GraphQL, gRPC). Work with vector DBs (e.g., ElasticSearch, Pinecone, Weaviate, FAISS) and RAG pipelines for knowledge-augmented reasoning agents. Support metadata and telemetry pipelines for LangSmith-based evaluation and observability. Security, Compliance & GovernanceBuild secure multi-tenant backend services with RBAC, API authentication, and tenant isolation. Ensure agent action auditability and reproducibility for compliance and governance. Collaborate on implementing platform guardrails (rate limiting, content filtering, safe tool usage). Testing, Observability & ReliabilityWrite automated test suites (unit, integration, load testing) for backend services.Implement logging, tracing, and metrics (OpenTelemetry, Prometheus, Grafana) for full observability. Participate in on-call rotations and improve platform resiliency and fault tolerance. 
Please note: This is a hybrid role that will be based in San Mateo, CA or Bellevue, WA and requires an in-office presence three days per week (Tuesday - Thursday).