Software Architect .NET/Backend Azure - Paris

As a Senior .NET architect, you will contribute to the technical design of the rewrite of an application currently developed using various technologies: .NET, IBM ACE, Service Fabric, Service Fabric.

The target solution will be in .NET, cloud native, containerized and hosted in Azure cloud.

You will design it keeping in mind the need for high resilience and performance.

About the context: The STP tribe operates messaging and group applications that ensure data, files, and messages are processed seamlessly end-to-end. This role directly contributes to that mission and contribute to the company strategy to embrace cloud and scale.

What you'll do

• Design & deliver modern integration services to replace/upgrade the communications layer (message/file ingestion, transformation, routing, delivery; synchronous and async models).
• Architect for resilience and scale: apply patterns such as circuit breaker, retries with backoff, timeouts, idempotency, outbox/inbox, DLQs, bulkheads, and compensating transactions/sagas.
• Design event-driven systems leveraging Azure messaging (Service Bus/Event Hubs) and/or Kafka-style pub/sub; define contracts, schemas, and versioning for backward compatibility.
• Design high-quality .NET services (.NET 7/8, C#, ASP.NET Core, worker services, gRPC/REST), with TDD as a default practice and strong emphasis on code quality, security, and performance.
• Design workloads on Kubernetes (OpenShift/AKS), using Helm and Git-based pipelines (Azure DevOps). Enforce enterprise container standards: image hardening, and Kubernetes network policies.
• Define observability: structured logging, tracing, and metrics (eg, App Insights/Splunk/OpenTelemetry); define SLOs and error budgets; build actionable runbooks. (Logging and cert management are first-class concerns in high-throughput messaging.)
• Collaborate in an agile product setup (Scrum), contributing to backlog refinement, DoR/DoD, iterative delivery, and cross-tribe ceremonies when needed.
• Lead and mentor: pair with, unblock, and coach junior developers; champion engineering best practices across the squad and Communities of Practice.

• 15+ years of professional software engineering, including 5+ years building mission-critical or high-throughput distributed systems (preferably in financial services or similarly regulated domains).
• Expert .NET engineer (C#, .NET 7/8, async/await, DI, testing frameworks).
• Azure hands-on experience: AKS, Functions, Service Bus/Event Hubs, Storage, Key Vault, Application Insights, Azure DevOps (Pipelines/Repos).
• Dapr/KEDA, gRPC, and API gateway experience.
• Containers & orchestration: Docker and Kubernetes (OpenShift and/or AKS), Helm, image life cycle, secure supply chain.
• Event-driven architecture fundamentals: pub/sub, event streaming, consumer groups, schema evolution, and exactly-once/at-least-once processing trade-offs.
• Test-Driven Development (TDD) and automation mindset; CI/CD pipelines and trunk-based development experience.
• Proven resilience engineering knowledge (timeouts, retries, circuit breaker, backpressure, outbox/inbox, DLQ, bulkhead, saga).
• Ability to work autonomously, make sound design decisions, and coach junior developers.
• Professional English (written and spoken).

Nice to have

• Observability stack: OpenTelemetry, Splunk, distributed tracing; performance and load testing at message/file-transfer scale.
• Knowledge of secure file exchange and enterprise integration patterns (SFTP/FTPS, AS2/AS4, MQ).
• Familiarity with financial messaging standards and non-functional controls (availability, integrity, confidentiality).