Back End Developer

We're building the infrastructure behind real-time voice interpretation. Our tool lets people speak their own language and be understood instantly, whether in a meeting, a taxi, or a video call. Not word-for-word translation, but real interpretation that preserves tone, meaning, and intent.

About us: We're a small, London-based voice AI startup with a working product and multiple modes (translate, share, connect, meet) designed for different real-world scenarios. The founding team is technical, and we're at the stage where the core product works and now needs production-grade backend infrastructure to scale.

The role: You'll be our second backend engineer, working directly with the technical founder. This is a build-from-scratch opportunity. You'll own the core backend infrastructure: designing the unified AI API platform, implementing billing and usage metering, architecting databases and data pipelines, handling high concurrency and auto-scaling, and maintaining real-time voice room infrastructure. You won't be slotting into an existing system. You'll be the person who designs and builds it.

What you'll work on:

• A unified API platform that packages our AI capabilities for scale
• Billing and usage metering systems
• Database architecture and data pipelines
• High-concurrency infrastructure with load balancing and auto-scaling
• Real-time voice room infrastructure
• Monitoring, logging, and analytics dashboards
• System stability, security, and performance optimization

What we're looking for: A backend engineer with 4-8 years of experience who's built production systems, not just maintained them. Strong Python skills are essential. You should be comfortable with distributed systems, cloud infrastructure (we use Azure), and database design. Experience with real-time systems is a strong plus given the nature of our product. Above all, we want someone who takes ownership, makes good decisions independently, and thrives with high autonomy in a small team.

What we offer: Competitive compensation, the chance to shape core infrastructure at a company tackling one of the hardest problems in voice AI, and direct impact from day one. You'll work closely with the founders in a hybrid setup (3 days in office near Liverpool Street).

• If you want to build something technically challenging from the ground up rather than maintain someone else's systems, we'd love to talk.