Software Engineer
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Before you apply
LocationBarcelona, Spain
Typefull-time
SenioritySenior
DepartmentEngineering
EquityIncluded
Company size5+ people
PostedAug 18, 2025 · 1y ago
Verified live2d ago
May no longer be actively hiring
Posted by the company on Aug 18, 202580% of this company's open roles have been listed for 90+ days
At a glanceSummarised by Seekless from the posting.
Fluent in modern Python and async programming
Experience building scalable, event-driven systems
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
Skills
Python
FastAPI
Asyncio
Redis
PostgreSQL
AWS
Terraform
React
GitHub
Datadog
Linear
LLMs
TTS
STT
browser automations
About the company
🚀 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
🧩 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
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Scale a real-time, event-driven backend architecture where milliseconds matter
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Design and implement low-latency APIs using FastAPI and Asyncio
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Solve engineering challenges in performance optimization, observability, and resilience
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End to end contributions from frontend to infrastructure.
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Collaborate on prompt engineering, LLM behaviors, LLM fine-tuning and UX
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Build and maintain infrastructure-as-code with Terraform and AWS
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Contribute to 0→1 product development with a small, fast-moving team
Our Stack
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Backend: Python, FastAPI, Asyncio, Redis, PostgreSQL
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Infra: AWS, Terraform, CI/CD
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Frontend: React
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Tooling: GitHub, Datadog, Linear
Bonus Points
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Experience with LLMs (prompting, training, alignment)
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Experience with TTS, STT and real-time voice
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Experience with browser automations
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Deep knowledge of AWS, Terraform, and distributed systems
•
Experience shipping 0→1 products in a startup
What You’ll Get
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Significant equity in a company backed by A16z
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Full ownership, real impact, and fast learning cycles
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A tight-knit team that values clarity, speed, and smart execution
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