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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Backend Engineer (LLM / AI Experience) - **Company:** Unith - **Location:** Barcelona, Spain (Remote available) - **Salary:** €50,000.0 - €65,000.0 - **Contract:** Temporary contract - **Skills:** Application Programming Interfaces (APIs), Artificial Intelligence, Amazon Web Services, Amazon Elastic Compute Cloud, Amazon S3, Computing Platforms, Cloud Computing, Program Optimization, Profiling, Code Review, Continuous Integration, Information Engineering, Database Queries, Distributed Systems, Python (Programming Language), Machine Learning, Performance Tuning, RabbitMQ, Redis, WebSocket, Data Logging, Chatbots, Large Language Models, Caching, Technical Debt, Backend, Fastapi, Kubernetes, Low Latency, Deployment Automation, Video Streaming, Functional Programming, Grpc, Docker, Golang, Microservices - **Published:** July 29, 2026 - **Apply:** https://www.adzuna.es/contact-us.html ## About the Role + 5+ years of backend engineering experience with distributed systems, microservices, and real-time architectures (WebSocket, gRPC, event-driven) + Experience building and deploying complex, highly-performant Python applications + 2+ years building LLM-powered products in production (2022-2025), including hands-on experience with LLM APIs (OpenAI, Anthropic, AWS Bedrock) and RAG systems + Comfortable balancing architecture design with hands-on implementation + Strong AWS experience with focus on performance optimization, observability, and production operations + Proven ability to optimize production systems (latency, throughput, technical debt) + Excellent collaboration skills across backend, infrastructure, and AI/ML teams Bonus Points + Golang experience + Experience with video streaming, media processing, or conversational AI platforms + Data engineering or ML model serving infrastructure experience ## Description We're looking for a Senior Backend Engineer with recent LLM product experience who combines strong architectural thinking with hands-on development. You'll work closely with the Head of Engineering, playing a key role in technical decisions while remaining deeply involved in day-to-day coding, feature delivery, and system optimization. You'll be a senior technical voice on the team - someone who designs systems and builds them. ️ What You'll DoArchitecture & System Operations (50%) + Actively participate in architectural decisions with the Head of Engineering + Collaborate with the Cloud Infrastructure Engineer on platform architecture, observability (monitoring, logging, alerting), and deployment strategies + Design and optimize systems: performance profiling, database queries, caching, and resource usage + Own production operations: troubleshooting, incident response, and on-call + Provide technical guidance through code reviews, design discussions, and best practices + Collaborate on real-time streaming architecture with the Video Synthesis Engineer Feature Development & Implementation (50%) + Implement backend features and services in production-grade Python and Go + Build conversation features: state management, history, and intelligence improvements + Implement multi-document knowledge bases using AWS Bedrock + Integrate LLM APIs (OpenAI, AWS Bedrock) and build RAG pipelines + Develop APIs and service integrations (gRPC, REST) + Work on core backend services: orchestration, caching, and platform APIs + Own testing, CI/CD pipelines, and deployment automation Tech Stack + Python (FastAPI) and Go (gRPC services) + AWS (S3, EC2, Lambda, Bedrock, managed services) + Docker, Kubernetes, RabbitMQ, Redis + LLM APIs (OpenAI, AWS Bedrock), + Backend systems you've built and maintained + LLM features you've implemented in production + A performance optimization project you worked on + Your experience with RAG or knowledge bases + Why digital humans excite you Apply via the Easy Apply button, or reach out directly to joyce@unith.ai - creativity is welcome Recruitment Process 1. Intro call with Joyce (30 min) 2. Technical interview with Head of Engineering & Product Manager (90 min) 3. Team meeting with backend video synthesis, and/or infrastructure engineers (90 min) 4. Practical exercise (short, relevant implementation task) 5. Reference check ️ Timeline: 2-3 weeks from application to offer Ready to make digital humans faster, better, and more reliable? Apply now Inscribirse en esta oferta Recibir ofertas similares por correo electrónico Al crear una alerta, aceptas nuestros Términos y condiciones y Política de privacidad, y el uso de cookies. ## Related Videos - [Boosting OpenSearch Performance: gRPC Search in Action](https://www.wearedevelopers.com/videos/1935-boosting-opensearch-performance-grpc-search-in-action) - [Reducing LLM Calls with Vector Search Patterns - Raphael De Lio (Redis)](https://www.wearedevelopers.com/videos/1714-reducing-llm-calls-with-vector-search-patterns-raphael-de-lio-redis) - [Go with the Flow: Stop the Leaks Before Your Memory's a Waterfall!](https://www.wearedevelopers.com/videos/100073-go-with-the-flow-stop-the-leaks-before-your-memory-s-a-waterfall) - [How to Avoid LLM Pitfalls - Mete Atamel and Guillaume Laforge](https://www.wearedevelopers.com/videos/1328-how-to-avoid-llm-pitfalls-mete-atamel-and-guillaume-laforge) - [gRPC Load Balancing Deep Dive](https://www.wearedevelopers.com/videos/1576-grpc-load-balancing-deep-dive) - [LLMs in the wild: Building an AI agent that survives production](https://www.wearedevelopers.com/videos/100319-llms-in-the-wild-building-an-ai-agent-that-survives-production) ## Related Articles - [What Are Large Language Models?](https://www.wearedevelopers.com/magazine/304-what-are-large-language-models) - [Dev Digest 121 - AI goes offline](https://www.wearedevelopers.com/magazine/456-dev-digest-121-ai-goes-offline) - [Dev Digest 132 - Binging WADFlix?](https://www.wearedevelopers.com/magazine/473-dev-digest-132-binging-wadflix) - [How to Become an AI Engineer](https://www.wearedevelopers.com/magazine/331-how-to-become-an-ai-engineer) - [From Prototype to Production: Build AI Agents with This Free 4-Course Learning Path](https://www.wearedevelopers.com/magazine/655-from-prototype-to-production-build-ai-agents-with-this-free-4-course-learning-path) - [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers)