Senior C# Developer
Expereo
Senior C# Developer
Expereo
Global connectivity and cloud migration services
Expereo · Katowice, Poland (Hybrid) · Full-time · Posted 2026-11-05
Workplace: hybrid
Department: Information Technology
Information is the lifeblood of every business. And no matter how small, each piece plays its part in transforming where that business can go. But it’s nothing if it can’t predictably get to where it needs to be. At Expereo, we understand how vital it is that applications run smoothly in every single location, giving information and teams a seamless experience.
For over 20 years, we have been designing, deploying and managing complex global networks, providing predictability, resilience and performance. Customers get one global experience, with full visibility, control and security through the Expereo platform. As the world’s leading provider of managed internet, SD-WAN, SASE and cloud connectivity, Expereo keeps enterprise and government sites running in 190+ countries. Fast, flexible internet helps every business get more done.
Fortune 500 enterprises trust us as a partner, and our people earn that trust. Talented teams from around the world make Expereo a place where everyone can do great work.
About the role
We are looking for a Backend Developer to join the Supplier onboarding and Quote Management teams and work directly on the computational core of our platform.
You will write dotnet every day. You will work on an existing C# backend and create new services. You will work on solving real-world business problems, like creating and translating our suppliers’ data, working on integrations with our partners and creating and maintaining internal tools.
The core of the role sits at the intersection of three things:
Algorithmic implementation: translating complex commercial requirements into deterministic, auditable logic. You will implement and maintain the engine that drives our quote-firming checks.
API design and contract maintenance: defining clear contracts between services, and ensuring the interface is clean, versioned, and reliable for downstream consumers.
Code quality and engineering discipline: making code production-ready and scalable: writing tests, applying engineering standards, and ensuring the codebase can grow with the platform.
You will work directly with the commercial teams, which handle the customer and supplier lifecycle from onboarding, through to quoting, delivery and billing.
Must Have
Strong proficiency in C#.NET Core.
Experience with API design, microservices, and integration frameworks.
Knowledge of CI/CD pipelines, automated testing, and observability tools.
Experience with enterprise integrations (e.g., ServiceNow) is a plus.
Strong Plus
Proficient in other backend languages (Python preferred)
Front end experience (like React, NextJS,..)
Familiarity with AWS Lambda/ECS/EKS, containerization (Docker/Kubernetes).
Nice to have
Experience with low-code platforms like Mendix or Salesforce.
Understanding of security best practices (RBAC, SBOM, dependency scanning).
Ability to work in a fast-paced, outcome-driven environment with cross-STO collaboration.
Mindset
Builder mentality with strong ownership.
Code-first, automation-first approach.
A full-stack learning approach to ensure team resilience.
Part of a team that is engaged and owning the things they do, highly trustable with direct commercial stakes.
Direct access to production systems, real data, and decision-makers. No layers of process between your work and its impact.
Exposure to cutting-edge technologies and large-scale global networks.
A role designed with trajectory in mind, the knowledge you build here is directly applicable to a senior technical execution path.
Competitive compensation
Hybrid Working
25 Days Holidays
Beyond the Job
We’re proud of our focus on as Environment, Social and Governance as well as the passion we display for the communities where we live and work.
EEO (Equal Employments Opportunities) Statement:
Expereo is an Equal Opportunities employer who aims to support and celebrate every employee that comes through our doors. We respect and support all of our people regardless of background, religion, nationality, sexual orientation, age, or physical condition.
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Expereo provides global connectivity solutions and managed network services to help businesses improve network performance and migrate to the cloud. It identifies, deploys, and manages tailored network solutions, moving organizations from legacy fixed private networks to flexible, agile connectivity and ensuring reliable, high-speed internet worldwide. Its products work by delivering end-to-end network services through service contracts and ongoing management, spanning deployment, monitoring, and optimization for each client’s needs. The company differentiates itself by serving a large enterprise base (including many Fortune 100 companies) with a global footprint and customized, managed connectivity offerings rather than one-size-fits-all solutions. Its goal is to enable digital transformation for enterprises by providing reliable, scalable connectivity and hands-on management to support cloud adoption and performance.
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