Staff Backend & AI Engineer, Madrid

Aircall is a unicorn, AI-powered customer communications platform used by 22,000+ companies worldwide to drive revenue, resolve issues faster, and scale customer-facing teams. We’re redefining customer communications by bringing voice, SMS, WhatsApp, and AI together into one seamless workspace.   Our momentum comes from a simple idea: help teams work smarter, not harder. Aircall’s AI Voice Agent automates routine calls, AI Assist streamlines post-call work, and AI Assist Pro delivers real-time guidance so people can do their best work. The result is higher revenue, faster resolutions, and teams that scale with confidence.   Aircall is headquartered in Paris, our European HQ, with a strong North American presence anchored in Seattle, our North American HQ, and teams across Madrid, London, Berlin, San Francisco, New York City, Sydney, and Mexico City. We’ve built a product customers love and a business that’s scaling quickly, backed by world-class investors and driven by rapid AI innovation across multiple product lines. At Aircall, you’ll join a company in motion. We’re ambitious, product-driven, and execution-focused, with visible impact, fast decisions, and real growth.   How we work at Aircall: We’re customer-obsessed, data-driven, and focused on delivering meaningful outcomes. We value ownership, continuous learning, and thoughtful speed. If you thrive in a collaborative, fast-moving environment where trust and impact matter, you’ll feel at home here. 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. Why join us?   🚀 Key moment to join Aircall in terms of growth and opportunities 💆‍♀️ Our people matter, work-life balance is important at Aircall 📚 Fast-learning environment, entrepreneurial and strong team spirit 🌍 45+ Nationalities: cosmopolite & multi-cultural mindset 💵 Competitive salary package & benefits 🏨 Medical, dental, and vision insurance is 100% covered 📈 401k plan with company matching! ✈️ Unlimited PTO — take the time you need to come to work feeling great! ⭐️ Wellness, commuter, and childcare reimbursements 💚 Generous parental leave policy   DE&I Statement:  At Aircall, we believe diversity, equity and inclusion – irrespective of origins, identity, background and orientations – are core to our journey.    We pride ourselves on promoting active inclusion within our business to foster a strong sense of belonging for all. We’re working to create a place filled with diverse people who can enrich and learn from one another. We’re committed to ensuring that everyone not only has a seat at the table but is valued and respected at it by providing equal opportunities to develop and thrive.     We will constantly challenge ourselves to make sure that we live up to our ambitions around diversity, equity and inclusion, and keep this conversation open. Above all else, we understand and acknowledge that we have work to do and much to learn.   Want to know more about candidate privacy? Find our Candidate Privacy Notice here. We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.