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Open nowPosted 439 days ago

Software Engineer

Supersonik5 open roles

Where
Barcelona
Work mode
On site
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Your applicationOpen nowSoftware EngineerSupersonik · Barcelona

  1. YouYes, apply to this one.

  2. CV RocketCV written for this posting.

  3. 25 readersRecruiter, hiring manager, skeptic. Round after round.

  4. CV RocketApplied on Supersonik's own form.

The reply lands in your private mailbox

3×more interviews than doing it yourself with ChatGPT.

The clock on this job

Early applications get read.

12.9% of postings close within 7 days. Measured by our own scanner across the market. Supersonik postings stay open a median of 6 days.

Share of postings closed within
  1. 2.2%1 day
  2. 4.7%3 days
  3. 12.9%7 days
  4. 21.0%14 days
  5. 35.6%30 days
  6. 58.5%60 days
This job: posted 439 days ago

Supersonik median: 6 days open

The posting

🚀 About Supersonik Supersonik 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. We’re backed by Andreessen Horowitz (a16z) and work with leading SaaS companies worldwide.

🧩 About the Role We’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: 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 Experience shipping 0→1 products in a startup What You’ll Get Significant equity in a company backed by A16z Full ownership, real impact, and fast learning cycles A tight-knit team that values clarity, speed, and smart execution

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    The review screen in CV Rocket: how each CV was read, round by round.

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