About Ragnar Solutions

Ragnar Solutions Romania is the Romanian branch of Ragnar Solutions BV, a growing software company based in the Netherlands.We build and maintain Deimos, an e-invoicing integration platform used for compliance accross PEPPOL (multi-country), France, Poland, Spain and more. E-invoicing is becoming mandatory in more and more countries, but every country has different rules, formats, and government systems. Deimos handles that complexity for our clients, helping make sure their invoices are processed correctly and delivered to the right systems on time.

About the Role

If AI writes all your code then this position is not for you.

We are looking for a Mid-level Full-Stack Developer to join the team building Deimos. You will own features end to end: from the CSV/SFTP intake and the background jobs that talk to national e-invoicing systems (Poland's KSeF, Spain's VeriFactu, the Peppol network) through to the Angular portals where clients see the result.

Our Stack

How it's built

• A multi-tenant platform: two Angular portals (client and admin), an API gateway in front of two ASP.NET Core APIs, and multiple .NET background services
• Services talk over RabbitMQ; calls to external systems go through an outbox with idempotent retries
• Integrations over REST, SOAP and SFTP, with XML built and validated against official schemas (Peppol BIS / UBL, Poland's FA(3))
• BackendC# 14 on .NET 10, ASP.NET Core
• Entity Framework Core with PostgreSQL
• RabbitMQ, Serilog
• xUnit and Moq
• Front-endAngular 20, standalone components and signals
• TypeScript, RxJS, Tailwind CSS
• Nx monorepo with libraries shared by both portals
• Playwright for end-to-end tests
• Tooling and InfrastructureDocker and Docker Compose
• GitLab CI for builds, tests and deployments
• HashiCorp Vault for configuration and secrets

What you will do

• Own features across backend, frontend, tests and docs
• Build and maintain integrations with national e-invoicing authorities
• Work with XML schemas: build documents, validate them, debug rejections from the authority
• Design background jobs: import pipelines, outbox-based sync workers, retries, idempotency
• Investigate production issues independently across services (logs, queues, database)
• Keep tenant isolation and authorization intact in everything you touch
• Review code and mentor junior developers

What we are looking for

• 3+ years professional C#/.NET, including ASP.NET Core APIs
• Solid EF Core and relational DB skills (PostgreSQL preferred): migrations, indexing, query performance
• Angular + TypeScript + RxJS, comfortable with forms, tables, reusable components; signals a plus
• Message-based / asynchronous processing (RabbitMQ or similar): at-least-once delivery, idempotency, retries
• Unit and integration tests as part of "done" (xUnit, Moq)
• Comfortable integrating third-party APIs (REST, SOAP) and reading XML/XSD
• Can debug a distributed issue on your own
• Git/PR workflow, gives useful code review

Nice to have

• E-invoicing, Peppol, UBL or any tax-authority integration
• Multi-tenant SaaS
• Docker Compose, GitLab CI, Vault
• File-based integrations (SFTP, CSV)
• Auth: JWT, FIDO2/passkeys, RBAC
• Nx monorepos, Playwright

What we offer

• Salary range between 7000 and 11000 RON (net), depending on experience
• Remote/hybrid working environment
• Meal tickets
• Medlife Gold private medical insurance
• End of year bonus
• Performance bonus
• Access to courses for continued professional development

Our hiring process

1. We keep it short and transparent: Intro call to talk about your background, the role, and what you are looking for.
2. Take-home assignment, described below.
3. Technical discussion (around an hour) where we go through your assignment together.
4. Final conversation with the team, and an offer.

About the take-home assignment

The assignment is a small full-stack task scoped to around 4 hours: a .NET API that accepts invoice-like records, a background worker that processes them from a queue (idempotent, with retries), and a small Angular page that shows the outcome. We care about how you structure and test it, not about polish. You have one week to hand it in.