Senior Developer

Senior Developer
atwork · Full-time · Remote within Spain or hybrid (Santander / Barcelona)
About the role
We are looking for a Senior Developer to work on our multi-tenant B2B SaaS platform, used by HR teams and by employees across the organisations we work with. The role combines hands-on development with architectural decisions and code review, and carries direct ownership of the areas you work on.
What you will do
Develop across the stack: .NET 10 and Entity Framework on the back end, Angular 21 on the front end, Azure SQL Database for persistence.
Participate in architectural decisions: service boundaries, data modelling, tenant isolation and API design.
Work on multi-tenancy, platform performance, our design system and integrations with third-party systems.
Review code before it is merged.
Write automated tests: unit and integration tests on the back end, Playwright UI tests on the front end.
Contribute to the management of our Azure environment and to infrastructure defined as code with Terraform.
Maintain technical documentation: architecture decisions, runbooks and onboarding material.
Work in an agile environment, collaborating with product, data science and design.
How we work
AI tools support our developers in their day-to-day work and are integrated into how we build software. Keeping that setup growing is part of the team’s work and part of this role. If you are excited about AI and where it is heading, you will have room to run with it.
What you bring
Bachelor’s or master’s degree in Computer Science or a comparable qualification
Substantial professional experience building and operating production web applications end to end (typically 5+ years)
Strong .NET and Entity Framework skills, with solid SQL Server experience
Extensive Angular experience
Proficiency with Git and a pull-request-based workflow
Demonstrated command of clean code, SOLID principles and testing methodology, with the ability to explain why, not only apply the rule
Experience working with AI coding agents and reviewing their output
Fluent English and Spanish
Nice to have
Multi-tenant SaaS architecture and tenant isolation experience
Infrastructure as code (Terraform) and hands-on Azure (App Service, Azure SQL, Redis)
Azure DevOps (repos, pipelines)
Experience configuring agentic development environments such as Claude Code, agent instruction files, MCP and custom tooling
A product-oriented mindset and experience working closely with Product Owners
Tech stack
.NET 10 · Entity Framework · Angular 21 · Azure SQL Database · Azure (App Service, Managed Redis, Azure OpenAI, Key Vault, Storage) · Terraform · Playwright and xUnit · Azure DevOps · Claude Code
What we offer
Full-time contract in a growing, international scale-up
Fully remote within Spain or hybrid in Santander or Barcelona, whichever suits you
Flexible hours, Fridays until 3 pm and reduced summer hours
25 holidays plus 2 additional Personal Time Off days
One additional week of salary or holiday per three years with us
Career Path & Learning budget
Cobee & Wellhub
Regular team events, including two team weeks a year on location
About atwork
atwork is a B2B SaaS scale-up on a mission to make HR a strategic business driver. Powered by our proprietary “AI Middle Layer”, atwork connects employee feedback, selected HR data, and business KPIs in a single platform, giving HR teams the power to act on feedback with predicted, quantified business impact, grounded in scientific precision.
We’re a diverse, remote-first team of psychologists, data scientists, and engineers spread across Switzerland, Germany, and Spain.
We look forward to hearing from you, and are happy to answer any questions along the way.

Work arrangement
Yes