Back to Careers page

Senior Full Stack Engineer with .NET


We are a healthcare technology company, and our mission is to help our clients build world-class products. We are proud that our first client is still our client. We trust our teams to deliver without constantly watching over their shoulders. And we have employees who have been with us for more than 20 years.


We are looking for a talented Senior Full Stack Engineer with .NET to join our efforts in building and growing an AI-powered tool for therapists and mental health professionals. You will join our agile development team in Bulgaria and collaborate with our stakeholders and colleagues in the US. Proactivity and self-discipline, exceptional collaboration and communication skills will be key for the successful candidate. Our product is called TheraPro ( It uses HIPAA secured artificial intelligence to summarize therapy sessions into progress notes. Notes can be easily copied and pasted into an Electronic Health Record system such as TherapyNotes or Simple Practice. Our technology stack includes .NET Core, Angular, Microsoft Azure, Containers (Docker) and MS SQL.


  • Participate in the Design, Implementation, Testing, Deployment, and Maintenance of new and existing data components, microservices, and UI components.
  • Participate in DevOps processes.
  • Take part in a team that transforms every task into an exciting, valuable experience.
  • Convert business needs into technical implementation.


  • Experience in deploying and supporting software using DevOps principles and tools (Azure Pipelines and Docker).
  • Experience with audio streaming and processing in software solutions.
  • Experience with SignalR.
  • Experience with Frontend Frameworks (Angular or other).
  • Experience in developing products in the healthcare sector.


  • Knowledgeable in Object Oriented Programming, Design Patterns, SOLID principles.
  • 7+ years of experience in developing software solutions in .NET (C#) or comparable framework.
  • Experience with relational databases (MS SQL preferred).
  • Team player with excellent communication skills.
  • Passionate – You search relentlessly for the right solution and would like to work with equally passionate people;
  • Humble – Focused more on the team than yourself; ability to disagree but commit to others’ ideas;
  • Hungry – Having a strong work ethic, determined to solve problems and get things done;
  • Smart – Intellectually, with an eagerness to learn; but also, emotionally, recognizing team dynamics;
  • Fluent in English.


  • A competitive salary and social benefits;
  • Quarterly performance review process;
  • Friendly work environment and nice attitude;
  • Work-life balance;
  • Modern and comfortable office close to the metro station “Konstantin Velichkov;
  • Opportunities for career development in an international company

Why We Do It? We care.

At OSI, we care about our clients, we care about each other, and we care about producing great software.

CLIENTS — We admit that the organization we most want to see succeed is our own. But we’ll quickly acknowledge that we can’t win unless our clients win. There’s no way around this symbiotic relationship. Fortunately, at OSI, we genuinely love to see our partners have breakthroughs in top-line growth, innovation and efficiency.

TEAM — If you’ve ever experienced the excitement that comes from being part a high-functioning team, you’ll understand why people matter. Trust. Accountability. Purpose. Self-confidence. These are all part of that exhilaration, but the whole is more than the sum of its parts. Great teams can get you through the tough times and can unlock greater potential than a group of individual contributors ever will.

PEOPLE – We care about individuals and humankind. That’s why we invest in talent and push people to do their best work. That’s also why we have given colleagues help when they’ve encountered personal crises; paid for surgeries people couldn’t afford; funded capital improvements and arts projects to improve our communities; and closed the office to attend colleagues’ weddings.

SOFTWARE – We care about the code that we write. We take pride in it. We constantly try to improve on it. We adopt best practices when they suit us. We geek out over data and make it work for us. We are not afraid to try the latest & greatest and to support the last year’s. We are ready to make mistakes and learn from them. We know that building great software requires a lot from us and we committed to it.


If this sounds like you and we look like the kind of people that you would like to work with simply reach out to us with your CV in English and anything else, you are proud of.

All applications will be treated as strictly confidential.
Only short-listed candidates will be contacted.

    Your name*:

    Your Email*:

    Your subject*:

    Your Message:

    Back to Careers page