About Replika

Replika is an AI companion loved by 35M+ users around the world. We’re redefining what it means to connect with technology — emotionally, intelligently, and personally. From mobile to VR, we’re building an experience that feels less like software and more like someone who gets you.

We’ve been featured in TED Talks, Stanford and Harvard studies, the Lex Fridman podcast. All for one reason: people connect with Replika in a deeply human way.

We're scaling fast and taking on bold challenges to become the most human AI on the planet.

About the Role

We’re looking for a Staff Applied AI Engineer to design and scale the systems powering Replika’s emotional AI. This is not an infrastructure or ops role—it’s a software engineering role focused on building robust APIs, integrating cutting-edge AI technologies, and delivering systems that scale. You will work directly with the CTO and partner closely with AI researchers and product teams to bring next-generation emotional AI to millions of users.

What You’ll Do

• Design and build APIs that deliver real-time emotional AI experiences at scale (sub-second latency for millions of requests).
• Integrate with industry-standard LLMs (OpenAI, Anthropic, LLaMA, Mistral) and vector DBs (Pinecone, Weaviate, Milvus).
• Apply AI developer frameworks such as LangChain, LangFuse, Guardrails AI, and emerging observability tools for LLMs (e.g., Weights & Biases, OpenTelemetry for AI).
• Lead design reviews, set technical direction, and ensure scalability and reliability of applied AI services.
• Collaborate with researchers to productionize models into robust APIs that work at consumer scale.
• Optimize for global growth: high-availability systems, cost-effective API integrations, and scalable embeddings search.

What We’re Looking For

• 10+ years of professional experience in backend software development (5+ Python required; FastAPI a plus).
• Deep experience with LLM APIs, embeddings, and vector DBs (Pinecone, Weaviate, FAISS, Milvus, etc.).
• Proven experience designing API-driven systems at scale (hundreds of thousands to millions of DAUs).
• Production level experience, and familiarity with AI frameworks such as LangChain, LangFuse, Guardrails, Haystack, or similar.
• Strong software engineering practices: testing, code reviews, performance optimization, API versioning.
• Docker experience (for packaging/deployment).
• Track record of collaborating across product, research, and engineering teams.
• Startup mindset: adaptable, hands-on, ownership-driven, fast execution, focus on what’s important.
• Knowledge of observability/monitoring for AI systems.

Nice to Have

• Experience with streaming data or real-time personalization.
• Prior exposure to conversational AI, gaming, or social platforms.
• Scala or other JVM languages.
• Experience in leadership roles such as Team Lead, Engineering Manager, or Staff Engineer

Why Join Us

• Direct impact: Your systems will touch tens of millions of users within months.
• Work directly with the CTO and be part of Replika’s core technical leadership.
• Push the boundaries of applied AI in a consumer setting.
• Fully remote across EMEA.

Work at Replika

At Replika, growth isn’t a maybe—it’s built in. Do the work. Deliver. One great project could double your salary. Seriously. Who do we think we are? Replika. We move fast. Very. Join us at the forefront of emotional AI.