Senior Full Stack Developer (React + .NET) | Tech6

Description

**About the opportunity** You will serve as the technical reference for evolving an established SaaS platform, used daily by thousands of users in the United States. This is a continuously operating product with direct business impact, high criticality, and real challenges in scalability, performance, and technological sustainability. We are seeking a senior developer with strong analytical ability, autonomy in decision-making, and architectural vision. More than executing tasks, we expect someone who influences technical decisions, contributes to the product’s engineering evolution, and elevates the team’s technical level. We are a team that values collaboration, close customer engagement, and shared responsibility for outcomes. We seek someone who identifies with this environment, enjoys knowledge sharing, supports colleagues, and contributes to resolving the product’s most critical challenges. We seek someone who understands the impact of their work on customers and has a genuine interest in building solutions that deliver value. **Responsibilities** * Develop and evolve front-end applications using React and TypeScript. * Design, implement, and maintain APIs and services using C# and .NET. * Participate in architectural definitions and strategic engineering decisions. * Analyze and resolve complex issues in production environments. * Ensure technical quality through code reviews, automated tests, and development best practices. * Optimize application and database performance. * Provide technical support to less experienced developers via mentoring and knowledge sharing. * Contribute to continuous improvement of development processes, CI/CD, and observability. * Collaborate with cross-functional teams to ensure consistent and sustainable deliveries. **Required qualifications** * Solid experience as a Full Stack Developer in production environments. * Advanced proficiency in React and modern front-end application architecture. * Strong experience with C#, .NET, and REST API development. * In-depth knowledge of SOLID principles, Clean Code, and Design Patterns. * Experience with relational databases, modeling, and query optimization. * Hands-on experience with automated testing (unit, integration, and/or E2E). * Familiarity with CI/CD pipelines and modern software engineering practices. * Ability to operate with technical autonomy and make well-founded decisions. **Preferred qualifications** * Experience with Azure or AWS. * Prior experience with large-scale SaaS platforms. * Knowledge of distributed architecture and microservices. * Experience with observability, monitoring, and production troubleshooting. * History of technical leadership or mentoring teams. * Experience in international projects and English communication. **What we offer** * Opportunity to contribute to an internationally significant product. * An environment with a high degree of technical autonomy and influence. * Real challenges in architecture, scalability, and product evolution. * An experienced and collaborative team. * Room for technical growth. * Health insurance subsidy. * Employee referral program. **Work model** **Contract: PJ or Cooperative.** **Join Tech6!**