Backend Engineer (Python/Scala)

Backend Engineer (Python/Scala)

📍 Hybrid in the Netherlands or 100% remote (EU time zone)

🗓 Start date: November–December 2025

Is this how you build software?

You see the backend as a living ecosystem — where data flows cleanly, APIs hum in harmony, and nothing ships unless it’s rock-solid.

You don’t just write code; you craft systems that stay fast, scalable, and production-ready — code that’s been battle-tested beyond the PoC stage.

You get a kick out of seeing millions of events stream smoothly through the architecture you helped design.

And when someone says, “We’re scaling from prototype to production,” — that’s when you’re at your best.

Why this role?

We’re scaling fast — new features, new clients, new challenges — and our platform processes over 200 million events every day.

You’ll be joining a small, senior engineering team building the next generation of Kaizo’s backend:
where Python powers our AI and LLM features (70%) and Scala drives our event-streaming core (30%).

You’ll take ownership of the full journey — from proof of concept to production-ready service — knowing when to prototype fast in Python and when to refactor for scale, security, and performance.

You’ll also play a crucial role in connecting our Scala engineering team and AI/Data Science group, ensuring our ML models, data streams, and backend systems work seamlessly together.

This is a hands-on role for an engineer who thrives on both experimentation and production rigour — comfortable prototyping in Python, and confident enough in Scala to ensure everything scales, performs, and holds up under load.

What you’ll be doing

• 🧠 Design and build RESTful APIs and streaming services that power Kaizo’s product and analytics layers.

• ⚙️ Develop features across Python (70%) and Scala (30%), from rapid prototypes to hardened production systems.

• 📡 Run data pipelines processing hundreds of millions of daily events using Kafka and Akka Streams.

• 🧩 Optimise performance — offload CPU-bound tasks, design batching/backpressure mechanisms, and tune reliability.

• 🔐 Implement security best practices (OWASP) to protect data and user trust.

• 🤖 Work with LLMs (OpenAI, Anthropic, Vertex AI, Groq, DeepSeek) and help shape scalable AI service patterns — batching, failover, rate limiting, retries.

• 🤝 Act as a bridge between our Scala engineers and AI/Data Science team, helping translate ideas, models, and data workflows into scalable production systems.

• 🪄 Collaborate closely with Product Managers and engineers to architect solutions that balance scalability, speed, and cost.

• 🧰 Contribute to architecture and technical strategy, and stay curious about emerging Scala/Python tools.

Requirements

What we’re looking for

We’d love to see:

✅ 3+ years of experience building backend systems with Python and Scala — strong in one, comfortable in both.
✅ Proven ability to design and optimise Python services under load — balancing I/O and CPU-bound processing, profiling bottlenecks, and knowing when to offload or parallelise workloads.
✅ Solid hands-on experience with Kafka, event-driven systems, and streaming architectures.
✅ Familiarity with Akka Streams or other streaming frameworks.
✅ Strong fundamentals in software design: clean APIs, testing, CI/CD, observability.
✅ Curiosity about AI/LLM stacks and scalable ML service design.
✅ A collaborative spirit and a growth mindset — we value engineers who own their work and elevate others.

Nice to have:
💡 Experience with AI gateways or streaming NLP pipelines

💡 Familiarity with TypeScript runtimes

💡 Security-minded development (privacy by design, PII handling)
💡 Monitoring tools like New Relic or LangSmith

Why Kaizo?

We’re not your typical SaaS company.

Kaizo builds an AI-powered performance platform for customer support teams.
We turn raw data into motivation — helping teams work smarter, perform better, and stay engaged.

Our product blends gamification and machine learning to make work more rewarding and more measurable.
And our engineering culture reflects that: collaborative, pragmatic, and built on trust.

Headquartered in Amsterdam, we work globally — across Europe, North America, and Asia-Pacific — with a fully international team and a remote-friendly setup.

We work as one product and engineering unit — backend, AI, and data science collaborating closely to deliver intelligent, scalable features that make customer support teams more effective.

What it’s like working here

👾 We move fast, trust deeply, and always aim for impact.
💬 We communicate openly — async or live (Slack is our second language).
🎯 We care more about outcomes than hours.
🧠 You’ll learn fast, stretch your skills, and shape real product evolution.

💥 Interview Process

• Intro call with Jo, our Talent Partner

• Deep-dive assessment with a follow up call with Marc and Samuel

• Chat with Dominik, our CEO

• Team Interview: the team jump on a call to say hi and you can ask them anything!

🚀 Ready to Apply?

If you love building systems that scale, streaming data that sings, and AI features that actually work — we’d love to meet you.

📩 Apply now

🌈 Equal Opportunities at Kaizo

We believe great people come from all walks of life.
We’re committed to building a diverse team and a workplace where everyone feels welcome, heard, and empowered to do their best work.