Senior Backend Engineer (FIX & Identity)

Company: Avenga
Location: Banja Luka, BA
Type:
Posted: Nov 7, 2026
Views: 3

✨ AI Summary

Avenga, an international engineering firm specializing in AI-native solutions, is hiring a Senior Backend Engineer in Banja Luka to build FIX protocol and identity services for a trading platform. The role requires 5+ years of backend experience, ideally in C#/.NET, with strong expertise in the FIX protocol, OAuth2/OpenID Connect, and event-driven systems. The tech stack includes MongoDB, Datadog, and SignalR, with a focus on financial accuracy and high-reliability infrastructure.

Avenga is an international engineering firm helping businesses operate with AI at the core. With 6,000+ experts worldwide, we combine engineering expertise with AI-native thinking to turn ambitious ideas into real-world impact across industries, technologies, and markets.

Core skills you’ll bring

  • 5+ years building backend systems, ideally in C#/.NET. Strong Java engineers are welcome too, and we will give you time to move to .NET

  • Real experience with the FIX protocol on electronic trading platforms in fintech or capital markets

  • Hands-on work with login and access control (OAuth2, OpenID Connect, IdentityServer or similar)

  • Designing and building APIs that other teams rely on

  • Solid experience with message-based, event-driven systems

  • Experience with financial calculations, such as pricing, where small rounding errors matter

  • Comfort with MongoDB or another NoSQL database

  • Some experience with monitoring tools such as Datadog, Sentry or Elasticsearch

  • Clear communication and a habit of working well with product, frontend and DevOps colleagues


Nice-to-have

  • Knowledge of fixed income or securities pricing

  • Experience with QuantLib or other quantitative finance libraries

  • Live data streaming with SignalR or WebSockets

  • Exposure to Pulsar, Databricks or Lakehouse setups

  • Some React and Redux for light frontend work

The impact you'll create

  • Build the services behind a trading platform, where speed and accuracy matter every day

  • Connect the platform to banks, brokers and venues through FIX

  • Make sure the right people have the right access across all our services

  • Shape how pricing and financial calculations are done, with exact results

  • Help keep the system reliable and easy to monitor as it grows

  • Share your experience with other engineers and help set good engineering standards

People are at the core of Avenga. We provide equal opportunities regardless of race, ethnicity, gender identity, sexual orientation, disability, age, religion, or any other characteristic. We are committed to a respectful environment where everyone can be themselves, share their ideas, and feel that they belong.

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About the Company

Name: Avenga
Location: 16 presence countries
Website: https://career.avenga.com

At Avenga, we believe that human creativity empowers technology that matters. We’re an international team of over 6000 curious minds, bold thinkers, and tech experts working together to build solutions that solve complex business and societal challenges.

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