Senior Full-Stack Engineer (Helsinki)

We’re looking for a Senior Full-stack Engineer with strong backend and infrastructure skills who takes ownership and ships with confidence. In this project you'll be focusing on Loyalty Personalised Content for over 2,5 million users/members. The team owns three systems that focuses  on ML-driven recommendations, promotional content and custom CMS for managing promo content. Experience of working with large databases and data-based recommendations is a great benefit.

Start: asap
Duration: end of 2026, extension possible
Location: Helsinki office 3 days/week
Language: Preferably Finnish (environment in Finnish), English also ok
Team: PO, Technical PO, Lead Engineer, Senior Full-Stack Engineers
Allocation: 100%
Industry: retail

What you'll do:

• Design and maintain REST APIs that deliver personalised content to downstream services, especially mobile
• Build and operate AWS infrastructure with Terraform – containerised workloads, monitoring, CI/CD
• Develop the content orchestration service and integrate recommendations from the Loyalty ML & AI team
• Collaborate across teams on API contracts, data flows, and integration points

What we're looking for:

• Stack: TypeScript, AWS, Terraform, Docker, PostgreSQL, OpenSearch, Kafka
• Product thinking: wants to shape what we build, not just how.
• 10+ years in software engineering, weighted toward backend systems.
• Production experience with TypeScript and REST API design.
• Deep AWS knowledge and hands-on IaC experience, preferably Terraform.
• Solid Docker and containerisation skills.
• Experience with relational databases, especially PostgreSQL

Especially valuable is:

• OpenSearch / Elasticsearch experience.
• Experience working with Kafka streams.
• An eye for data engineering or machine learning – not a pro, but someone who spots ways the team's data can augment our services.
• Observability and monitoring know-how.

Interested? Please contact @Lisa_Witted in Slack / lisa.sandstrom@witted.com