Desenvolvedor(a) Full Stack .NET - Sênior

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Desenvolvedor(a) Full Stack .NET - Sênior based in Brazil.

As a Senior Full Stack .NET Developer, you will build, evolve, and sustain critical digital solutions within a complex financial and regulatory ecosystem.

You will work closely with Tech Leads, Product Owners, and QA professionals to turn well-defined specifications into reliable, testable software.

The role combines strong backend engineering with integrations, distributed systems, SQL optimization, and occasional Angular development.

You will also work with AI coding agents in a controlled, reviewable, secure, and auditable development workflow.

Your contributions will directly support the modernization of legacy systems and their adaptation to new digital financial infrastructure.

You will be encouraged to influence technical decisions, improve engineering practices, and contribute to a culture of quality and continuous learning.

This is an opportunity for a senior engineer who values autonomy, technical excellence, traceability, and meaningful engineering challenges.

Accountabilities:

• Develop APIs, services, business rules, and integrations using C#, .NET, and ASP.NET Core.
• Build and maintain clean, testable, observable code that follows the squad's architectural standards and engineering practices.
• Translate version-controlled specifications and acceptance criteria into robust implementations, proactively identifying and challenging ambiguities before development.
• Develop synchronous and asynchronous integrations with legacy systems, registrars, and other participants in the ecosystem according to defined contracts.
• Implement resilient application patterns, including error handling, idempotency, retries, timeouts, circuit breakers, and reprocessing strategies where appropriate.
• Design and optimize SQL queries, indexes, relational data models, and persistence strategies, while supporting basic performance diagnostics.
• Create and maintain unit, integration, and contract tests, ensuring test data is secure, reliable, and reproducible.
• Use AI agents to accelerate development activities while maintaining human review, security controls, testing standards, and full traceability.
• Record development progress, technical decisions, limitations, and relevant findings in the appropriate project artifacts.
• Participate actively in code reviews, pair programming, refinement sessions, daily meetings, demonstrations, and retrospectives.
• Contribute to technical documentation, including OpenAPI specifications, READMEs, changelogs, and architecture-related materials.
• Investigate failures across CI, testing, and production environments using logs, metrics, and traces.
• Support the Tech Lead in continuously improving the team's knowledge base, development practices, and AI-agent harness rules.
• Contribute to front-end maintenance and enhancements in Angular when required, including components and integrations.

Requirements:

• Solid professional experience with C#, .NET, ASP.NET Core, and REST API development.
• Strong knowledge of object-oriented programming, SOLID principles, design patterns, dependency injection, async/await, error handling, and automated testing.
• Proven experience with relational SQL databases, including data modeling, query development, indexing, and basic performance troubleshooting.
• Experience developing and supporting microservices, APIs, system integrations, and messaging-based architectures.
• Knowledge of application resilience, idempotency, observability, and security practices.
• Hands-on experience with Git, pull requests, code reviews, and CI/CD pipelines.
• Ability to work effectively in regulated environments, following access controls, data protection requirements, and audit-evidence practices.
• Strong communication skills and autonomy to transform technical specifications into implementation and comprehensive tests.
• Familiarity with Angular and TypeScript is a plus.
• Experience with AWS services such as ECS/EKS, SQS/SNS, CloudWatch, IAM, or Bedrock is desirable.
• Knowledge of Kafka or RabbitMQ is an advantage.
• Experience with Docker, Terraform, or AWS CDK is desirable.
• Familiarity with DDD, hexagonal architecture, CQRS, event-driven architectures, or legacy modernization is a plus.
• Experience using Claude Code, GitHub Copilot, or an equivalent AI development agent in a real-world engineering workflow is desirable.
• Background in payments, credit, receivables, banking, or financial integrations is considered a strong advantage.
• A degree or ongoing studies in Computer Science, Information Systems, Software Engineering, or a related field may be relevant, although equivalent professional experience can also be considered.

Benefits:

• Opportunity to work on challenging technology and modernization initiatives within a complex financial ecosystem.
• Exposure to modern software engineering practices, cloud technologies, distributed systems, and AI-assisted development.
• Collaborative environment with experienced technology, product, and quality professionals.
• Opportunities to contribute to technical standards, architecture, knowledge sharing, and continuous improvement.
• Access to an environment that values professional development, community, and knowledge sharing.
• Opportunities to participate in technology communities, training initiatives, and development programs.
• International exposure through collaboration within a globally expanding technology ecosystem.
• Inclusive workplace culture focused on diversity, respect, ethics, and collaboration.
• Remote-friendly work environment, according to the applicable position and project arrangement.