AI Engineer (f/m/x)

Hey, it's great that you've found us. Are you ready for a challenge? Perhaps we have just the right opportunity for you. At holi.social, we believe in the power of community and want to help people turn their ideas into reality and make a positive impact together.

That's why we're working to create a new digital ecosystem. A digital hub that removes obstacles for all involved, allowing them to channel their energy into the social projects they believe in. At the same time, we're building the digital home for social initiatives with the goal of collectively scaling their impact digitally. To learn more about holi, we invite you to have a closer look into our vision and dive into our web app.

To make this vision reality, we’re building powerful tools behind the scenes - and that’s where you come in.

About the role

Our Data & Matching team is building the data backbone for social impact. We develop intelligent recommendation systems that connect people with the opportunities where they can make the greatest difference - turning intention into meaningful action.

You'll be working closely with our Product Manager to develop ambitious product visions and transform them into appropriate and evolvable technical solutions. We have already created a few data pipelines, but we are looking for someone that can take our efforts to the next level in creating a production-grade data infrastructure that is cost efficient and flexible.

What You'll Build

Data Infrastructure & Pipelines

• Design and maintain robust data pipelines for recommendation
• Build a data architecture supporting content-based and behavioural recommendations
• Ensure high data quality, freshness, and reliability in production systems
• Crawl and enrich external data sources, calculate embeddings for matching algorithms

Product-Driven Recommendations

• Extend our recommendation system across all content types (e.g. volunteering opportunities, events, posts, etc.)
• Power personalized content feeds, search results, and recommendations using behavioural data
• Implement smart filtering (e.g. hide previously viewed content, boost content with higher engagement probability)
• Design A/B testing frameworks to validate recommendation performance

Strategic Technical Leadership

• Co-create a long-term data strategy and roadmap with Product Management
• Break down complex product ideas into feasible technical phases
• Challenge current approaches and bring modern data stack perspectives
• Drive technical decisions balancing innovation with pragmatic delivery

Core Technical Skills

• Production experience building and evolving data pipelines
• Strong background in recommendation systems (content-based, collaborative filtering, behavioural)
• Experience with modern data stacks and cloud platforms (preferably Google Cloud)
• Understanding of data quality testing, monitoring, and observability
• A sound engineering background

Product & Communication Excellence

• Think from the users perspective - you want to solve real problems, not just build cool tech
• Excellent written and verbal communication for our remote-first environment
• Ability to translate technical complexity into clear business impact

• Experience validating features and measuring success in production

Working Style

• High autonomy with strong alignment - you can drive initiatives independently while staying connected with the team
• "More engineer than scientist" - you apply sound methodologies but focus on shipping reliable solutions
• Strategic thinking - you can be a sparring partner for product and technical strategy, not just an executor
• Curious about the latest innovations in AI & data engineering

Our Tech Stack
We build holi in a way that allows the vast majority of people to participate, regardless of the device they are using. That's why we're building a web technology-based foundation for cross-platform apps that work on popular mobile devices as well as on computers.

The app is based on an up-to-date React Native codebase that drives Expo-delivered mobile apps and a Next.JS web app. The frontends connect to a monolithic Django/Python-based backend and a range of Deno Typescript services via Apollo-mediated GraphQL. The data pipeline codebase you’ll spend most of your time in is written in Python, uses Prefect as task orchestrator, processes data from BigQuery & Google Cloud Pub/Sub, uses Vertex AI and ingests into Typesense as search engine & vector database.

We already achieved a high grade of automation with regards to Continuous Integration, Testing and Deployment and are at home in the Google Cloud Platform. We are Open Source, if you’re interested in details, check our documentation.

Find your WHY: holi.social is changing the way people engage in social causes - empowering initiatives to thrive and individuals to take meaningful action. Join us and become part of a growing movement for social impact.

Remote-first: Work from anywhere in Europe with flexible hours (CET ±2). Join us for biannual retreats, and help shape social change through technology. Prefer in-person connection? You're always welcome at our offices in Hamburg or Berlin.

Flexible time off: We believe in balance. That’s why we offer a minimum of 25 vacation days - with no set maximum. Whether you need rest, time with family, or space for personal growth, it’s all possible here.

Genuine team spirit: Beyond our digital routines, we come together at least twice a year for in-person co-working, connection, and shared learning. The Data & Matching team also gathers annually for dedicated team-building activities.

Give back: Every quarter, you can use one workday to support a social cause close to your heart.

Mental Health First: Your wellbeing matters. We have trained Mental Health First Aiders on our team and provide all employees with access to Nilo Health’s mental health support platform.

Recruiting Process:

1. Cultural Fit Interview

2. Case Study & Technical Interview

3. Meet the team 

Ready to turn data into social change? 

If our mission resonates with you, we'd love to get to know you better. Send us a few lines about yourself and why we should connect. If you have any questions, don't hesitate to reach out to us.

Let's create change together – perhaps with you on our team. We're excited to hear from you!