Senior .NET Backend Developer (C#/.NET Core/Fintech) - Full Remote Portugal

ABOUT THE OPPORTUNITY

A high-stakes fintech environment is looking for a Senior .NET Backend Developer with genuine experience in trading, brokerage, or financial services platforms. This is not a generic backend role — the client operates live financial systems where performance, security, and reliability are non-negotiable. If you've built and supported backend services in a regulated financial context and take pride in clean, scalable architecture, this is a strong opportunity to work on meaningful, complex systems from anywhere in Portugal.

Language: English B2 minimum | Level: Senior | Location: Portugal-based, fully remote

PROJECT & CONTEXT

You'll be working on backend services and application integrations within a fintech platform, connecting back-office systems with in-house and third-party applications. The environment is live and demanding — you'll be expected to design, build, and support production-grade systems where traceability, security, and data integrity are critical. The stack centres on modern .NET, with RESTful APIs, domain-driven service architecture, and SQL Server or Oracle data layers.

WHAT WE'RE LOOKING FOR

• At least 4+ years of C# and .NET backend development experience in production environments
• Minimum 2 years of hands-on experience with .NET Core 8 or .NET 10
• Proven experience in application integration — connecting back-office systems with in-house and third-party platforms
• Strong command of RESTful API design and domain-driven service architecture principles
• Mandatory: prior hands-on experience in fintech, trading, or brokerage projects — this is a hard requirement, not a nice to have
• Experience optimising database queries and data access layers in SQL Server or Oracle
• Solid knowledge of secure coding practices and financial data handling requirements
• Familiarity with API versioning, OAuth/JWT authentication, and integration patterns
• Experience supporting live production systems — tracing issues, diagnosing root causes, and delivering fixes under pressure
• Ability to deliver scalable, maintainable backend services using modern .NET practices
• Strong problem-solving and analytical skills with the ability to work independently across multiple workstreams
• Clear communication skills in English (B2 or above)
• Based in Portugal, available to work fully remotely

NICE TO HAVE

• Experience with event-driven architectures or message brokers (e.g., Kafka, RabbitMQ) in financial contexts
• Familiarity with CQRS and Clean Architecture patterns in .NET solutions
• Exposure to cloud platforms (Azure, AWS) in fintech deployments
• Knowledge of financial regulatory requirements or compliance frameworks (e.g., MiFID II, PCI-DSS)
• Experience with Docker/Kubernetes in production backend environments

Compensation: €2,050 – €2,700/month net, depending on experience and seniority level.

Why HumanIT people stay (4.4 Glassdoor, 89% recommend)

- 15th month salary
- Health insurance covering your family
- Birthday off
- Mobility program for digital nomads
- Real work-life balance

Full benefits https://www.humanit.pt/careers/#perks
What it's really like https://www.humanit.pt/careers/#work-at