Principal Software Engineer, Programmable Comms

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 Team: Communications Platform is the part of Aircall that makes a call connect, a message arrive and a number work. Voice, messaging, numbers, carriers, routing and the APIs on top of them. Every product Aircall sells, from the Workspace to our AI voice and messaging agents, runs on it. That platform is changing shape. Aircall is becoming an AI-native company, and the systems we built for humans on web and mobile now have to serve AI agents as first-class users and participants. That means programmable, well-contracted voice and messaging, reliability that holds as agent traffic grows, and cost that works at enterprise volume, not just in a demo. Key Responsibilities: As a Principal Engineer you set the technical direction for that evolution. You are based in Communications Platform, but at this level your influence is company-wide: the decisions you make shape how every other engineering team builds on voice and messaging. You'll be one of a small group of Principal Engineers in the department, each with a distinct area of focus, working together on a shared architecture. What the job involves:

• Setting technical strategy, Define and drive the target architecture for the platform, write it down, get it adopted, and keep it honest as reality changes.
• Align it with where the business and the product are going.
• Solving the hardest problems, Take on the challenges with the biggest business impact and the least obvious answers, across several domains at once, and lead them from problem definition to production.
• Raising the bar, Set quality standards in architecture, security and DevOps, and make the right way the easy way.
• Lead the TDD and ADR process on the decisions that span teams.
• Leading on reliability, Own the long-term reliability and performance strategy for a tier-1 platform: target architecture, resilience and DR posture, SLOs and the KPIs that show up in roadmap trade-offs.
• Making AI compound, Identify where AI can fundamentally change our architecture, our engineering workflows and our cost structure.
• Lead build-versus-buy decisions, and establish the principles and reference architectures that stop AI adoption from fragmenting.
• Growing people, Mentor and coach engineers and engineering leaders across teams, and help shape what senior technical growth looks like here. Qualifications: What We're Looking For You have set technical strategy across several teams or domains and can point to architecture that others have successfully built on. You have deep experience designing and operating large-scale, high-availability distributed systems . Experience in real-time communications — such as VoIP, SIP, WebRTC, media, messaging, or carrier networks — is a strong plus. You understand products and customers , not just systems. You anticipate business needs and translate them into clear technical direction. You have led reliability at scale , including: SLOs and reliability standards Incident management practices Resilience and disaster recovery Capacity planning Performance and latency You use AI to work at a higher level yourself , and you have thought seriously about designing systems with non-deterministic components, including: Failure modes Observability Guardrails Human-in-the-loop approaches You influence and persuade through clear writing, strong technical judgment, and sound reasoning , rather than seniority. You are comfortable navigating ambiguity, complexity, and disagreement . You actively make the engineers and teams around you better. Required Skills & Experience 10+ years of experience building and operating production distributed systems, with significant time spent in technical leadership roles. Strong cloud experience, ideally with AWS , together with hands-on experience with Kubernetes and the operational realities of running services at scale. A security-first mindset , with practical experience in observability and incident management. The ability to credibly review code, architecture, and technical designs across the different stacks and domains you influence. Fluent written and spoken English . What This Role Is Not Not a people management role. You will have no direct reports; your influence comes from the quality of your technical judgment, communication, and leadership. Not a detached architecture role. You will stay close to the code, technical designs, production systems, and incidents. How We'll Measure Success in Your First Year A clear and agreed technical direction for the platform , visibly reflected in team priorities and quarterly plans. At least one significant cross-domain technical challenge moved from an open question through to production. A measurable improvement in reliability standards and practices , consistently applied across the platform. Other engineering teams are able to build on the platform more easily , with fewer escalations and dependencies required to move forward. Engineers around you are visibly developing toward Staff and Principal-level engineering roles . 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 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 judgme