Senior .NET Engineer

Project overview

Objective: strengthen the team with a senior contractor capable of delivering complex features autonomously, in a 'you build it, you run it' logic.

Stakeholders: Core Engineering Manager / Staff Engineer, Product Managers, UX/UI designers, engineering teams of the Client, Merchant, and User tribes.

Hands-on engineering

Design, develop, test, and maintain .NET microservices and shared SDK NuGet packages, consumed by all tribes.

Contribute to the technical design of new features and refactorings. Propose and defend domain breakdowns in design reviews.

Apply and extend the team's architecture patterns: Clean Architecture, DDD, CQRS/MediatR, event-driven patterns, Outbox pattern.

Address performance, scalability, and security challenges of a multi-tenant platform.

Technical quality and engineering practices

Contribute to code quality, performance, security, and observability of the team's services.

Take ownership of the 'run': service health, incident management, blameless postmortems.

Follow and improve engineering practices: CI/CD on Azure DevOps, automated tests, code reviews, ADRs, documentation, pair programming.

Cross-functional collaboration

Work with the Engineering Manager or Staff Engineer on planning, risk management, and delivery trade-offs.

Work with Product Managers and UX/UI designers to build realistic, high-value solutions.

Represent the team's technical perspective in tribe and platform-level discussions.

Expected deliverables

Production code (microservices, SDK NuGet packages) delivered via reviewed pull requests, with automated tests.

Technical documentation and ADRs for design decisions made.

Contribution to the 'run' of the team's services (incident management, postmortems).

Profile sought

Experience

5+ years of professional experience in software engineering.

Real-world exposure to production under load: operated services for which they were responsible for the 'run' (service health, incidents, scaling, contention, infrastructure costs).

Proven ability to deliver complex features autonomously and to support the skill development of more junior engineers.

Technical skills

Strong expertise in .NET / C# and distributed systems on Azure.

Good understanding of Clean Architecture, DDD, CQRS / MediatR, microservices, MongoDB, PostgreSQL, Kubernetes, CI/CD on Azure DevOps.

Modern practices: automated tests, observability, performance tuning, postmortems, ADRs.

Advanced practice of AI-assisted development, beyond simple prompting: AI across the entire engineering cycle (design, implementation, tests, review, debugging), delegation of well-defined tasks to coding agents, systematic verification of all AI-generated output.

Concrete experience with OAuth2 / OIDC, identity management, and authorization on a multi-tenant platform (tokens, scopes/claims, roles and permissions, tenant isolation).

Concrete experience with asynchronous processing:

messaging: idempotence, retries, dead-letter queues, eventual consistency, Outbox pattern;

scheduled jobs / batchs: scheduling, error recovery and restart, monitoring.

Ability to investigate an incident end-to-end across the entire stack: logs, traces, and metrics, monitors/alerts, MongoDB and PostgreSQL queries, Kubernetes pod behavior.

Soft skills and languages

Excellent communication, including explaining technical topics to non-technical stakeholders.

Team spirit, rigor, autonomy, pragmatism in decision-making.

Fluent English and French (mandatory).

Work environment

Mission

Design, deliver, and run in production shared .NET microservices and SDK NuGet packages for the team, as an autonomous contributor. Also contribute to the improvement of the team's working methods, tooling, and best practices.

Project details

• Start: ASAP
• Duration: 1 an renouvelable
• Remote: hybrid
• Location: Paris, France, FR
• Languages: French