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Backend .NET Developer

Paris, Ile-de-France💼 Full-time🗓 2026-06-21 → 2026-08-05

Core

Designing and developing robust payment APIs and modules for card, wallet, and PSP flows, ensuring resilience and performance in monetary transaction management.

Role type

Backend .NET Developer (Payment Systems)

Builds

Payment APIs, payment method eligibility modules, connectivity with payment partners, and transaction management systems.

Domain

Fintech / Payments / Financial Services

Deliverable

production ML models | product features | dashboards & analysis | research | client delivery | infrastructure | physical/clinical work

Required skills

C# .NET 10, Web API, MS SQL, Payment flows (CIT/MIT, 3DS, retries, idempotence), Messaging systems (Kafka), Azure Container Apps, Observability tools (Datadog)

Preferred skills

Microsoft Dependency Injection, Dapper, xUnit, Moq, Postman, CI/CD (GitLab), AI usage for time-to-market improvement

Technologies

.NET 10, MS SQL, Kafka, Azure, Datadog, GitLab, Postman

Responsibilities

Designing and developing various payment modules including payment method eligibility and connectivity with multiple payment partners; Designing, developing, and maintaining robust payment APIs; Contributing to card (CB), wallet, and PSP flows including authorization, capture, refund, and 3‑D Secure (3DS); Improving the resilience, performance, and quality of the payment information system; Implementing unit tests; Documenting the developed APIs.

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