Senior .NET Backend Engineer - FinTech & FIX Protocol in Warsaw

KARIER in Warsaw, Poland, seeks a strong backend engineer with fintech focus to help design scalable microservices in .NET, MongoDB, Redis, RabbitMQ, Pulsar, and Elasticsearch. You will collaborate with a 7-person engineering team and contribute to API design and distributed systems. The ideal candidate has 5+ years of backend development, deep C# / .NET experience, and hands-on knowledge of FIX Protocol, quantitative finance libraries like QuantLib, OAuth2/OIDC, and NoSQL databases.