AI Developer - LLM Applications

Reaktor Group konserni; Helsinki; Hybrid; EUR 70,000 - 110,000; Full time

Benefits offered by this job

Top-spec computer and phone

Unlimited phone plan

Lunch benefit

Recreational benefit (sports & culture

Extensive occupational healthcare

Family support

Extensive insurance package

Juice program

Equal opportunity employer

Job summary

Reaktor is seeking AI developers in Helsinki to design and build end-to-end AI-enabled applications. You’ll work across backend, frontend, and infrastructure, integrating OpenAI and open-source LLMs, and deploying in cloud environments with Docker and Kubernetes.

You’ll contribute to end-to-end AI use cases, participate in RAG pipelines, and collaborate with client teams to choose the right technologies. A passion for solving real human problems with AI is essential.

Qualifications

• Experience building AI-enabled applications in production
• Experience deploying AI apps in cloud env (Azure, AWS, GCP) with containers
• Knowledge of vector databases (pgvector, chromaDB, pinecone) and data privacy considerations
• Familiarity with end-to-end AI use cases and client collaboration

Responsibilities

• Designing and implementing end-to-end LLM-enabled applications from backend to frontend.
• Integrating commercial and open-source LLMs into production workflows.
• Working with RAG pipelines, embeddings, vector databases and guardrails.
• Designing evaluation pipelines to benchmark model performance and safety.
• Collaborating with cross-functional teams to address complex business challenges.
• Helping clients pick technologies suitable for their needs.

Skills

LLM integration

Backend development

Frontend development

Cloud deployment

DevOps / CI/CD

Python

Node.js/TypeScript

PostgreSQL / vector DB

Tools

Docker

Kubernetes

LangChain

FastAPI

LlamaIndex

PostgreSQL

pgvector

ChromaDB

Pinecone

Job description

Reaktor's award-winning tech community is looking for AI developers to join us in Helsinki.

If you thrive on applying cutting-edge AI technologies, building LLM-powered applications, and driving projects through the full software development lifecycle — and you’re passionate about solving real human problems with a holistic approach — we’d love to meet you. Join us to experience a truly collaborative, low-hierarchy environment where your curiosity and ideas can make a real impact.

As an AI Developer at Reaktor, your job is to be an expert in a range of AI-related software development responsibilities spanning the entire software development lifecycle, from front-end to production.

Your daily tasks include:

• Designing and implementing end-to-end LLM-enabled applications from backend architecture to user-facing components, ensuring scalability and maintainability.
• Integrating commercial and open source LLMs (e.g. OpenAI, Anthropic, Meta Llama etc.) into production applications and workflows, using APIs or fine-tuning.
• Working with end-to-end RAG pipelines, including embeddings, vector databases (e.g. PostgreSQL + pgvector, chromaDB, pinecone), robust prompt engineering strategies and guardrails
• Designing and implementing evaluation pipelines to benchmark the model performance and safety
• Collaborating with cross-functional teams, contributing to the development of AI use cases to address complex business challenges
• Working together with the client’s tech and business teams and helping them to pick the right technologies suitable for their needs.
• Delivering the client and the team with world-class technical expertise.
• Developing the agentic software development process and ways of working, to better leverage the use of AI.
• Other software development-related tasks like contributing to the overall software architecture and design, building test automation and debugging problems.

You are a curious-minded AI developer who is comfortable working with LLMs, backend, and front-end of an application. Additionally, you understand the role of infrastructure and understand the underlying workings of transformer-based models.

To thrive in this position, you’ll need:

• Experience working with AI software development technologies (LLMs, backend, frontend, ops, and consulting skills) in a production environment.
• Experience in deploying AI applications in cloud environments (Azure, AWS, GCP) with containerization/orchestration (Docker, Kubernetes)
• We don’t have a hard limit on years of experience, but we’ve noticed that some of these competencies take several years to accumulate.
• Foundational knowledge in DevOps, including Continuous Integration (CI), automated deployment, and test automation.
• Know-how on vector databases and databases (e.g., PostgreSQL + pgvector, pgvectorscale, chromaDB, pinecone).
• Awareness of data privacy (GDPR), security and ethical considerations when handling sensitive data with AI.
• To be comfortable engaging with the client stakeholders when needed.
• Fluent verbal & written Finnish and English skills.

RE: Technologies in our projects

• Some projects require proficiency in Python or Node.js/TypeScript, including experience with frameworks like LangChain, FastAPI or LlamaIndex.
• Some projects require JVM-based languages.
• Our philosophy is that tech is a tool. This role is quite new to the industry and there will be some grey areas when it comes to exact techs in our projects. Do not let lack of a specific technology hinder you from applying to this job.

For two decades, we’ve been developing qualities and capabilities for adapting, reacting, and supporting change – building Reaktor to hold up in a fast-paced environment while ensuring the well-being of our people.

At Reaktor, you'll have the opportunity to work across a range of industries, such as Healthcare, the Public Sector, Industrial and Retail. You might also be collaborating with clients in Defense & Security, Aero or Gaming & Entertainment.

Read more about the different industries we work with here .

While working at Reaktor, we’ll provide you with:

• The ability to impact how you work. Together with the client, your team chooses the approach, technologies, and methodologies you think will work best in any given situation.
• A community with as much support as your heart desires.
• A team that’s not only experienced but considerate as well – they all want you to succeed.
• A sustainable work-life balance and support for your daily life outside of work. (e.g., free moving day, Reaktor car share, sick child care services, office space to use for your private events, etc.).
• An opportunity to grow as a professional. In addition to the day-to-day work, we offer internal training courses, community events, and 15-minute coffee breaks to discuss hot topics in tech and design.
• A possibility to take part in more extended academy-like studies like Cloud Academy.
• 300+ hobby clubs, from winter swimming and running to knitting and archery, that bring people together outside of (and sometimes inside) office hours. Many of these are supported by Reaktor.

Together, we are committed to making Reaktor an environment that embraces and values all of our employees for the whole of who they are. We encourage applicants from all backgrounds to apply, knowing that studies show that members of underrepresented communities don’t apply for jobs unless they fully satisfy all of the requirements. If you're thinking twice about applying for this reason, we invite you to send us your application anyway. You could be just the person we're looking for.

At Reaktor Helsinki, our benefits and perks evolve with our community, and we’re always open to new ideas that will support the wellbeing of Reaktorians. Currently, we offer the following perks:

Tools

We offer everyone a top-spec computer and a phone of their choosing to work with and use at work and home. If you need other tools, like a keyboard or a mouse, we'll figure it out, too!

Phone & internet

To keep you connected, we’ll cover an unlimited phone plan – and a proper internet connection to your home.

We offer the monthly lunch benefit in addition to your salary, which means you only pay the taxes.

Recreational benefit (sports & culture)

At Reaktor, the recreational benefit is an addition to your salary – and it’s tax-free.

If you want one, we offer an optional commuting benefit card and a bicycle benefit.

Extensive occupational healthcare

Extensive occupational health care services include specialists’ appointments, operations, vaccinations, dental care, and mental health services, including e.g. psychotherapy.

Family support

We support all types of families with encouraging types of parental leave and more, offering support for child care.

An extensive insurance package

Our extensive insurance package safeguards you for accidents, travel, and more.

Our subsidized massage deals keep those shoulders nice and loose.

The Juice-program enables you to work on open source projects – and get compensated for it!

We're an equal opportunity employer

All applicants will be considered for employment without attention to race, color, religion, sex, sexual orientation, gender identity, national origin, veteran or disability status.

FAQ

01 What are we looking for?

We believe there’s more that matters than just the resume. We’re looking for an exciting overlap of curiosity, creativity, people skills, and experience: people who are willing to learn, participate, and share new perspectives.

02 What does the hiring process look like?

We take the time to learn about your skills and aspirations and help you learn about ours. Our interview process usually involves three or four conversations over the course of a few weeks. From application to closing, our process takes about four weeks. Your recruiter will keep you up to date on what to expect from each stage of our interviewing process.

03 What kinds of projects do you have?

We do a variety of different kinds of projects, with the aim of each being meaningful and critical to a client’s business. Our typical engagements are from 6 months to 18 months and involve between 3-6 Reaktorians collaborating closely with our clients. When it comes to picking and choosing, we look at a number of things from the business side. For example, we tend to be interested in the multi-functional growth potential of the project as well as the technological and digital maturity of the client, their product, and the project overall. However, not all good business is a good fit for us culturally. We only take on new business that aligns with our values, is interesting for our people to work on, and has a great local or global impact.

The core idea behind how we staff is that you will never be alone in a project. When staffing our projects, we first start by going through your preferences and ambitions for learning, be it customer location, the field of business, or some particular technology. We then go through your learning and self-development targets and do our best to match all of the above to a project. We get multiple projects and new openings in existing projects each month. If there isn’t a perfect fit immediately, we try to find a spot for you in an existing project or take some time while you work on internal projects, or get deeper into onboarding.

05 What do people do in between projects?

Client work is our number one priority, but we’ve gotten pretty good at making the most out of the normal in-between time in the consulting business. Maybe you’ve just joined us, your project has just ended, or you’re rotating ...

06 Is it ok to work remotely?

It depends on the project in question, as we choose the option that fits best with each client. Sometimes projects are multisite, at other times, there are more on-site visits, and on rather rare occasions, we are 100% remote. That said, we love to see each other every once in a while and spend time together at get-togethers and occasional in-person meetings.