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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Full Stack Java Engineer (React) - **Company:** Aperia Solutions, Inc. - **Location:** United States (Remote available) - **Experience:** Expert - **Contract:** Permanent contract - **Skills:** Java (Programming Language), .NET Framework, Spring Security, Application Programming Interfaces (APIs), Amazon Web Services, Amazon S3, HTML5, Bootstrap (Software), Cascading Style Sheets (CSS), Cloud Computing, Code Review, Information Systems, Continuous Integration, Relational Databases, Database Schema, Software Design Patterns, Payment Systems, Windows Communication Foundation, Junit, PostgreSQL, Enterprise Messaging Systems, Microsoft Message Queuing, MySQL, Model View Controller (MVC), OAuth, Performance Tuning, Scrum Methodology, RabbitMQ, Mockito, Systems Integration, Web Services, Data Logging, ReactJS, Spring-boot, Software Security, Backend, Integration Tests, Information Technology, Reactive Programming, Front End Software Development, Restful APIs, Terraform, Dynatrace - **Published:** July 17, 2026 - **Apply:** https://www.indeed.com/viewjob?jk=536896edf65d81ca ## About the Role Job Description We're seeking a Senior Full Stack Developer comfortable across backend, frontend, and cloud/infrastructure. You'll design, build, and maintain secure, high-performance payment systems and integrations. The ideal candidate has strong Java/Spring Boot experience, React front-end skills, relational database expertise (MySQL/Postgres), messaging/event-driven architecture experience, and practical AWS and infrastructure-as-code exposure. Testing discipline, API security (OAuth2/JWT), and familiarity with distributed tracing are important., * Minimum 4 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). Eligibility Requirements * Must be willing to submit to a background investigation and drug test as part of the selection process. ## Description Summary Join Aperia Solutions, a fast-growing FinTech and managed consultancy building B2B accounts payable and payments platforms. You'll join a mid-size, distributed team working across the full stack - from Terraform infrastructure to Spring Boot services to 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., * 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 or equivalent) 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. ## Related Videos - [Migrating half a million users to a new payment service provider](https://www.wearedevelopers.com/videos/730-migrating-half-a-million-users-to-a-new-payment-service-provider) - [How Unit Testing Saved My Career](https://www.wearedevelopers.com/videos/1642-how-unit-testing-saved-my-career) - [Keeping applications secure by evolving OAuth 2.0 and OpenID Connect](https://www.wearedevelopers.com/videos/100152-keeping-applications-secure-by-evolving-oauth-2-0-and-openid-connect) - [MySQL Protocol Features You Should Be Aware Of](https://www.wearedevelopers.com/videos/100267-mysql-protocol-features-you-should-be-aware-of) - [Build and Deploy a Fullstack App with Open Source Tooling](https://www.wearedevelopers.com/videos/775-build-and-deploy-a-fullstack-app-with-open-source-tooling) - [From boy scouting to redrawing the landscape](https://www.wearedevelopers.com/videos/1140-from-boy-scouting-to-redrawing-the-landscape) ## Related Articles - [React Developer Salary [2023]](https://www.wearedevelopers.com/magazine/198-react-developer-salary-2023) - [Fully Remote Software Engineer Jobs](https://www.wearedevelopers.com/magazine/447-fully-remote-software-engineer-jobs) - [Find a Developer Job: 12 Best Job Sites For Developers](https://www.wearedevelopers.com/magazine/165-find-a-developer-job-12-best-job-sites-for-developers) - [Frontend Developer Salary in Germany [2023]](https://www.wearedevelopers.com/magazine/195-frontend-developer-salary-in-germany-2023) - [Dev Digest 121 - AI goes offline](https://www.wearedevelopers.com/magazine/456-dev-digest-121-ai-goes-offline) - [Highest Paying Tech Companies for Developers](https://www.wearedevelopers.com/magazine/220-highest-paying-tech-companies-for-developers)