About SupersonikSupersonik helps B2B SaaS companies sell faster with AI-powered product demos. On a live video call, our AI Agent shares the screen to walk buyers through a personalized, interactive demo in any language. This lets teams skip long sales calls and focus on closing deals.

Si le interesa solicitar este empleo, por favor, asegúrese de cumplir los siguientes requisitos que se enumeran a continuación.
We’re backed by Andreessen Horowitz (a16z) and work with leading SaaS companies worldwide.
About the RoleWe’re hiring Senior Engineers to join our core team in Barcelona.
You’ll be solving complex, technical problems and shaping the product and architecture from day one. You should thrive in high-growth startup environments, be fluent in modern Python and async programming and know how to build scalable, event-driven systems. You care about fast, real-time systems and enjoy working at the intersection of performance, AI and great user experience.
If you love solving first-principles problems, navigating ambiguity and want to build a product people love you’ll fit right in.




What You’ll Work On
- Scale a real-time, event-driven backend architecture where milliseconds matter
- Design and implement low-latency APIs using FastAPI and Asyncio
- Solve engineering challenges in performance optimization, observability, and resilience
- End to end contributions from frontend to infrastructure.
- Collaborate on prompt engineering, LLM behaviors, LLM fine-tuning and UX
- Build and maintain infrastructure-as-code with Terraform and AWS
- Contribute to 0→1 product development with a small, fast-moving team

Our Stack
- Backend: Python, FastAPI, Asyncio, Redis, PostgreSQL
- Infra: AWS, Terraform, CI/CD
- Frontend: React
- Tooling: xghoner GitHub, Datadog, Linear

Bonus Points
- Experience with LLMs (prompting, training, alignment)
- Experience with TTS, STT and real-time voice
- Experience with browser automations
- Deep knowledge of AWS, Terraform, and distributed systems

📌 Software Engineer (Barcelona)
🏢 Supersonik
📍 Barcelona