Senior Full-Stack Engineer

Company Description LVJ Soft helps organizations optimize software development and operations, adopt transformative technologies, and drive sustainable growth. The company focuses on delivering actionable insights and practical implementations that improve engineering efficiency and product quality. We are looking for an experienced Senior Full-Stack Engineer to join a growing FinTech platform. The ideal candidate will have strong hands-on experience across mobile development, backend services, databases, and AWS infrastructure, with a focus on application security, performance, and scalability. Responsibilities Develop and maintain cross-platform mobile applications using React Native for iOS and Android. Build, maintain, and troubleshoot backend services using Python and Node.js. Design and maintain REST APIs and third-party integrations. Manage and optimize MySQL databases, including queries, indexing, and performance tuning. Support AWS production infrastructure, including EC2, RDS, IAM, and VPC. Maintain CI/CD pipelines and support production deployments. Diagnose and resolve application, database, and infrastructure performance issues. Apply secure coding practices and troubleshoot production incidents. Review code, document critical workflows, and contribute to architectural improvements. Requirements 7+ years of professional software engineering experience, or equivalent demonstrated senior-level experience. Strong hands-on experience with React Native for both Android and iOS. Strong backend development experience with both Python and Node.js. Solid experience designing and maintaining REST APIs. Strong experience with MySQL or similar relational databases. Hands-on AWS production experience, particularly with EC2, RDS, IAM, and VPC. Experience building or maintaining CI/CD pipelines. Strong understanding of application performance, scalability, and secure coding practices. Proven ability to troubleshoot complex production systems and work independently with existing codebases. Preferred Qualifications Experience in FinTech, banking, payments, lending, or financial-data integrations. Experience with AWS S3, SQS, Lambda, and API Gateway. Experience with load testing, capacity planning, microservices, and application security testing. C# and modern .NET / .NET Core backend development experience. Experience developing or supporting ASP.NET Core REST APIs, services, or microservices. Show more Show less