About the Role We are seeking a Senior Backend & Infra Engineer to help shape the core infrastructure powering Pika's products. In this role, you will operate at the intersection of systems engineering and advanced AI, taking ownership of the unified architecture that supports our platform—from real-time messaging and scalable APIs to cognitive agent runtimes and orchestration frameworks. You will architect and build robust, distributed backend systems enabling autonomous AI agents to reason, use tools, recall memories, and act across multiple platforms at scale. This high-ownership position means your architectural decisions will directly impact how millions of users experience generative AI. As a senior engineer, you’ll also play a key role in raising the technical bar through guidance, RFCs, code reviews, and mentorship. What You'll Do - Architect Distributed Systems: Build scalable backend, infrastructure, and agentic services for Pika’s web, mobile, and multi-platform products. - Evolve the Agent Runtime: Design and optimize the core execution loop that handles agent reasoning, tool-use frameworks, function calling, memory retrieval, and multi-step orchestration. - Design Real-Time Architecture: Own and scale real-time messaging infrastructure, event-driven architectures, WebSocket connections, and pub/sub patterns for throughput, latency, and reliability. - Implement Core AI Capabilities: Optimize LLM integrations, multi-provider model routing (Claude, GPT, Gemini, open-source), context window management, cost optimization, and streaming responses. - Build Memory & Retrieval Systems: Design semantic search and vector-based embedding infrastructure to handle long-term memory, working memory, and episodic recall for autonomous agents. - Own Backend Logic End-to-End: Drive database modeling (SQL/NoSQL), API design, performance tuning, and production reliability for high-traffic pipelines. - Drive Technical Excellence: Write RFCs, evaluate complex technical trade-offs, mentor junior engineers through code reviews, and build alignment across engineering and product teams. What We're Looking For - Experience: 5+ years of software engineering experience building production services at scale, with 2+ years hands-on with LLM-based orchestration, multi-agent systems, or agentic solutions. - Backend Mastery: Deep proficiency in modern backend technologies (Node.js, Python, Go) and frameworks (Express, FastAPI, TypeScript, etc.). - Systems & Infra Knowledge: Strong understanding of distributed systems, event-driven microservices, message queues, cloud infrastructure (AWS/GCP), Kubernetes, and CI/CD workflows. - AI & Agentic Expertise: Solid grasp of LLM capabilities and limitations, prompt engineering (system prompts, chain-of-thought, structured output), tool-use execution, and embedding models. - Real-Time Patterns: Comfort designing and debugging real-time streaming pipelines, long-polling, and highly concurrent networking setups. - Product & Data Intuition: Deep understanding of database design and the product sense needed to make an AI system feel "alive" and responsive. - Mindset: Ownership mentality—identify systemic bottlenecks and ship solutions without waiting for exact specifications. Strong communication and a collaborative, team-first attitude. Nice to Have - Experience with multi-modal AI architectures (image generation, TTS, speech-to-text, video generation) - Experience with agent frameworks (LangChain, CrewAI, AutoGPT) or building custom, high-performance execution runtimes - Experience with fine-tuning, RLHF, or DPO pipelines - Background in multi-tenant SaaS or internal tooling and operational automation - Previous startup experience—comfortable with ambiguity and rapid experimentation - Competitive coding background (IOI, ICPC, Olympiad medalists, etc.) What We Offer - Competitive salary in the AI industry - Equity in a fast-growing startup shaping the future of AI - Comprehensive health benefits, monthly stipends, company retreats - A supportive and collaborative office culture—we’re all building and launching together About Pika At Pika, we’re crafting a future where video creation is seamless, intuitive, and universally accessible. Our vision is a world where videos serve as a canvas for everyone's unique expression, not just entertainment. Harnessing AI's transformative power, we aim to remove the technical barriers that have traditionally limited video production. We focus on building the best technology to empower creativity—not only within our products, but as a core part of our culture. We are a small, energetic team of smart and curious individuals valuing efficiency, collaboration, and creativity. We're looking for team members with sharp intellect, a strong work ethic, and the ambition to make a meaningful impact. You’ll find significant growth opportunities here, supported by a culture that nurtures both individual and collective development. Our headquarters is in Palo Alto, CA, and we work from the office 3-5 days a week.