Senior Full Stack Developer (Java, React) at Aperia Solutions

Join **Aperia Solutions**, a fast-growing FinTech and managed consultancy building B2B accounts payable and payments platforms. You’ll work with a mid-size, distributed team across the full stack—from **Terraform** infrastructure to **Spring Boot** services, **React** interfaces, and database migrations. Aperia serves banks, processors, payment facilitators, merchant service providers, ISOs, and government entities. This role offers technical ownership, a collaborative culture, and opportunities to shape product and architecture.

Core Responsibilities

• Design, create, maintain, and optimize applications using **Spring Boot** (MVC and WebFlux), **React**, and the Microsoft/Java tech stack where applicable.
• Translate business requirements into functional, secure, and scalable solutions.
• Build and maintain APIs (REST), integrate messaging queues, and implement async/event-driven patterns.
• Manage DB schema design and migrations for MySQL/PostgreSQL; optimize queries and performance.
• Participate in infrastructure-as-code efforts (**Terraform**) and deploy to multi-environment AWS (ECS, Lambda, RDS, S3, SSM).
• Secure APIs using OAuth2/**Spring Security** with JWT and policy-based authorization.
• Maintain, upgrade, and refactor existing codebases to improve efficiency and performance.
• Write and maintain unit and integration tests (JUnit, Mockito), and support CI/CD and observability (**OpenTelemetry**/distributed tracing).
• Collaborate with product, QA, and distributed engineering teams; participate in Agile sprints and code reviews.
• Ensure error-free code that follows best practices, design patterns, and security standards.
• Mentor peers, investigate and resolve production issues, and support continual improvement.

Functional Responsibilities

• Work with Business Analysts and US-based stakeholders to clarify requirements.
• Propose technical approaches and detailed implementation plans.
• Implement daily tasks, investigate issues, and support team members to deliver high-quality work.
• Perform unit and cross testing; document results.
• Conduct technical research and internal training.
• Other duties as assigned.

Required Technical Skills & Experience

• Minimum 6 years hands-on experience with Java and **Spring Boot** (MVC and/or WebFlux/Reactor).
• Strong experience with **React**, REST APIs, HTML5, CSS3, and Bootstrap-based responsive UI.
• Solid experience with relational databases (MySQL, PostgreSQL): schema design, migrations, and performance tuning.
• Experience with messaging systems (RabbitMQ, AWS SQS/SNS, or similar) and event-driven patterns.
• Practical AWS experience (Lambda, ECS, S3, RDS, SSM).
• Knowledge of OAuth2/**Spring Security**, JWT, and policy-based authorization.
• Testing discipline with JUnit, Mockito, or similar frameworks.
• Strong understanding of performance, security, best practices, and design patterns.
• Experience with Web Services; familiarity with WCF or .NET is a plus but not required.

Desirable Experience (will separate you from the rest)

• Fintech/payments domain knowledge (ACH, NACHA, reconciliation, FBO models).
• **Terraform** or equivalent IaC and multi-environment infrastructure management.
• Deep experience with reactive programming (Mono/Flux).
• Observability experience: **OpenTelemetry**, distributed tracing, metrics, and logging.
• Hands-on experience with multi-tier/layer distributed applications.
• Comfortable working in Agile/Scrum environments and with distributed teams.
• Strong communication skills.

Education or Certifications

• Bachelor’s Degree in Computer Science, Information Systems, or related field (or equivalent experience).