Senior Software Engineer - Backend

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. Within Aircall, we are launching a specialized New Product Unit to build the future of autonomous sales. We are improving the AI Orchestration Layer—a system that records and understands every customer interaction (calls, video, email, WhatsApp) to autonomously execute sales workflows: CRM updates, follow-ups, task creation, and coaching insights.  Our long-term vision is to evolve this into a self-improving, agentic Sales OS—where specialized AI agents collaborate, coordinate, and continuously optimize the revenue process. The Role We’re looking for a strong Senior Python Engineer who’s eager to go beyond traditional backend development. This role is for someone ambitious—someone who takes pride in building things well, but knows how to move fast in a startup environment. You strike the right balance between clean architecture and pragmatism, between perfection and progress. You’re energized by hard technical problems—distributed systems, AI orchestration, architectural trade-offs, performance, and scalability. You can go deep when needed, but you’re equally focused on shipping, learning, and iterating quickly. You’re curious by nature, committed to continuous improvement, and excited to bring the most effective modern approaches—whether agentic patterns or AI-augmented development workflows—into real-world production. This isn’t just another engineering role. It’s an opportunity to help build the intelligence layer behind a next-generation autonomous Sales OS.   What You’ll Do • Design and implement production-grade Python services with clean architecture and strong engineering discipline. • Architect scalable, distributed systems using Domain-Driven Design (DDD) principles. • Integrate with external SaaS systems (CRMs, dialers, meeting tools, OAuth providers). • Optimize performance, latency, cost, and reliability of AI-driven systems. • Build and orchestrate LLM-powered agents (planning, reasoning, tool usage, memory). • Develop internal frameworks to manage: • Agent coordination • Tool execution • Memory layers • Event-driven workflows • Work closely with AI engineers, product, and founders to transform complex sales workflows into autonomous processes. • Use AI coding assistants effectively and experiment with AI-augmented development workflows. What We’re Looking For • 7+ years of strong backend engineering experience. • Advanced Python expertise (async, typing, architecture patterns, testing) • Experience designing scalable distributed systems. • You design thoughtful, well-architected systems and write clean, high-quality code, with a focus on performance and long-term maintainability. • Experience with GCP (preferred) or AWS. • Mindset: You’re energized by building systems that can reason and take action—not just generate responses. • You actively leverage AI coding assistants and are driven to push the boundaries of AI-augmented engineering. • You thrive in fast-paced startup environments where ownership is real and impact is immediate. • Strong communication skills are essential—you’ll collaborate closely with Product, Design, and Business stakeholders, and stay deeply connected to our users and the problems they’re trying to solve. • Fluency in English is required; Spanish is a plus. Tech Stack • Backend: Python, FastAPI, Celery, PostgreSQL, uv (package-manager) • Frontend: NextJS, Tailwind • DevOps: Google Cloud, Kubernetes 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 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 are strongly committed to hiring a diverse and multicultural team and we encourage applications from traditionally underrepresented backgrounds.