Senior Backend Engineer (.NET) - FinTech

About the role

Avenga, an international engineering firm with more than 6,000 experts worldwide, is looking for a Senior Backend Engineer specializing in .NET for a FinTech project. You will design and build scalable backend services and APIs, integrate FIX protocols for electronic trading, and develop financial calculation engines and pricing models.

Key responsibilities

• Design and develop scalable backend services and APIs using C#/.NET.
• Build and maintain FIX integrations for electronic trading workflows.
• Develop financial calculation engines, pricing models and quantitative algorithms.
• Implement secure authentication, authorization and identity solutions.
• Build event-driven microservices using distributed messaging technologies.
• Optimize data processing and storage using MongoDB, Redis and Elasticsearch.
• Improve system reliability through monitoring, telemetry and automated testing.
• Collaborate with cross-functional teams, contribute to architecture and mentor engineers.

Required profile

• 5+ years of backend development experience with strong C#/.NET and ASP.NET Core skills (Java also acceptable).
• Experience designing scalable APIs, microservices and distributed, event-driven systems.
• Hands-on experience with the FIX protocol in capital markets or electronic trading.
• Strong communication and cross-functional collaboration skills.

Required skills

• Authentication and authorization with OAuth2, OpenID Connect or IdentityServer.
• Financial calculations, pricing engines or quantitative models with QuantLib or similar libraries.
• MongoDB and messaging technologies such as RabbitMQ or MassTransit.
• Observability tools such as Elasticsearch, Datadog or Sentry.
• Understanding of numerical precision and financial market conventions.

Nice to have: knowledge of fixed-income instruments and securities pricing; Pulsar, Databricks or lakehouse architectures; Redis, event sourcing, SignalR or WebSockets; React, Redux or Rematch; mentoring experience and architectural contributions.