Senior Backend & AI Engineer - Kuba English
Thanks to AI, we want to make language learning more fun, more effective, and more accessible than ever before. We focus especially on conversational skills.
💡 About us:
We've successfully built an MVP with an agency in Prague, and are now focused on conquering the CZSK market by the end of 2024.
Our app, Kuba English, inspired by the dynamic and unconventional teaching style of Jakub Čáslava (@kubovaenglish), has already captured the attention of over 220k followers and been purchased by thousands.
We're a tight-knit team of three, all born between '94 and '97, with strong backgrounds in sales, marketing, and management - but we're missing the tech expertise.
🚀 Our next goal?
Expanding into key regions around Europe with Kuba English.
Scaling through a franchise model (think of new apps, such as French, Spanish, German).
We need a technical leader to build the infrastructure that powers multiple language learning brands across Europe.
🎯 What You're Walking Into
We shipped the MVP with an agency (Applifting), then switched to an internal team to scale.
Our current backend dev is leaving for a new opportunity, so we’re hiring a Senior Backend Developer to take over backend ownership.
You’ll inherit the system, optimize and scale it, and drive AI innovation = agentic workflows, faster feature delivery, and clean code that the whole team can be proud of.
Current Tech Stack:
- Backend: Python, PostgreSQL, SQLAlchemy + Alembic, Cloud Functions, FastAPI
- AI/LLM: ElevenLabs + OpenAI/Google APIs for conversations, image generations, grammar feedback, TTS, STT
- Infra: Google Cloud Platform
- Mobile: Kotlin Multiplatform (KMM) for shared logic, SwiftUI (iOS), Jetpack Compose (Android)
- Integrations: Stripe, RevenueCat, DatoCMS, Firebase, Mixpanel, Adjust....
✅ Who We’re Looking For:
We need a Backend Developer knowledgeable with Python to help us grow our platform’s capabilities. Ideally a real founder for Startup.
5+ years backend experience with Python (we run Python 3.12+)
Strong experience with FastAPI and designing REST APIs
Solid backend fundamentals: PostgreSQL, NoSQL, webhooks, background jobs / async processing...
Hands-on experience integrating AI/LLM APIs (OpenAI/Anthropic/Gemini similar APIs)
AI-first mindset: practical, product-driven, not hype-driven
Excited about agentic workflows and modern AI stacks
Experienced with Google Cloud Platform (Cloud Functions, Cloud Run, Firestore)
Docker basics is a plus
Startup mindset = you can work autonomously, ship fast, iterate based on data
English fluency (even though we're Czechs and Slovaks)
Strong Plus:
- Mobile backend experience - Understanding iOS/Android requirements
- LLMOps - Prompt engineering, evaluation, cost optimization
- You follow AI research but ship production code
📊 What You’ll Do:
Build and maintain scalable backend infrastructure.
Collaborate closely with Mobile developers to secure smooth integration between the backend and our iOS/Android apps.
Optimize performance, handle datasets, and ensure a fast and secure user experience. You are a problem-solver who can write clean, efficient, and scalable code.
🧠 And big plus for the synergy:
Thinks big but starts small: You understand the startup grind, but you’re always thinking ten steps ahead.
Loves to be challenged and challenge others: You’re ready to push boundaries, innovate, and disrupt the status quo.
Has a track record of success: Whether you’ve built apps, led tech teams, or launched products, you’ve done it, and you’ve done it well.
🎁 What We Offer:
apart from essential tech gear, including a notebook and phone of your choice
A front-row seat in a high-energy startup with the potential to impact millions of learners worldwide.
The freedom to shape the technology and the product—your ideas and expertise will be at the forefront.
The opportunity to work with a passionate team that’s all-in on our mission.
140,000–160,000 CZK / month (based on experience and fit). Final offer confirmed after the probation period.
📝 Interested? Let's talk about it. Apply now and let’s create something amazing together!
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We’re building a company to be successful, fast-growing, and valuable. But that alone isn’t enough — we’re also building a place where we genuinely want to work. That means people come first: we don’t expect anyone to change who they are just to show up to work. Collaboration is a positive force in our lives, not something we endure for a paycheck. And it means we see diversity as a strength.