Staff Backend & AI Engineer, Madrid

The Role

As a Staff Backend & AI Engineer, you will be responsible for the design, development, deployment, and operation of business-critical AI features. Previous experience implementing AI features is a must. Best practices, evangelization, and mentoring in your team and across all of Engineering will be a part of your day to day job. Quality, excellence, and agility drive our delivery processes and you will help us level these up. You will be building practical applications such as chatbots, virtual assistants, automated content generation, and other NLP-powered tools. You will use and fine-tune existing LLMs to cater to specific business needs and domains, ensuring high performance in real-world applications.

Your Responsibilities @ Aircall

Collaborate on requirements analysis to design the right technical and business solutions for our customers.

Propose innovative solutions by staying ahead of AI landscape trends and emerging technologies.

Own key responsibilities in the design, architecture, and end-to-end delivery of AI-driven modules.

Write clean, scalable, and maintainable code while ensuring proper testing, deployment, and monitoring.

Continuously improve code quality through regular refactoring, debugging, and performance enhancements.

Contribute to building secure, high-quality AI solutions that power Aircall’s customer experience.

Optimize product and platform performance and ensure reliability through live site monitoring.

Participate in an on-call rotation to handle critical incidents and maintain system uptime.

Qualifications:

AI experience is a must for this position: Strong knowledge of LLMs and hands-on experience building with them - including usage, prompting and model integration.

Familiarity with AI frameworks (e.g., LangChain, LlamaIndex, AutoGen) and modern AI architectures such as RAG, vector databases, reranking, and performance optimization.

5+ years of experience in back-end development using Python, TypeScript/Node.js, or Java, with a focus on security, scalability, availability, and performance.

Full-stack development experience is a strong plus.

Nice to have: Ideally you will have worked with AWS in a production environment and understand how to design for, deploy on and get the best out of, the environment and services provided by Amazon.

Security is at the forefront of your mind in everything that you do.