Hiring | Senior Java/.NET Integration Engineer | San Antonio, TX | Contract

Role : Senior Java/.NET Integration Engineer
Location : San Antonio, TX
Duration : Long-term Contract

Position Overview

We are looking for a highly experienced Senior Java/.NET Integration Engineer with strong hands-on experience across Java, .NET/C#, REST APIs, application integration, and enterprise application development.

The ideal candidate will be a versatile senior engineer who can work across multiple applications and technology stacks rather than being narrowly specialized in one platform. The candidate should be able to quickly understand existing systems, learn new SDKs and technologies, develop and integrate APIs, troubleshoot complex issues, and provide technical mentoring to internal development teams.

Java is the primary technology focus, with strong .NET capability required or highly preferred.

• Design, develop, and maintain enterprise applications using Java and .NET/C#.
• Develop and integrate RESTful APIs across multiple applications and platforms.
• Design and implement reliable application-to-application integrations.
• Work with Java, Spring/Spring Boot, .NET Core/.NET 6 and C#.
• Develop and maintain microservices and integration services.
• Analyze existing applications, interfaces, dependencies, and integration points.
• Troubleshoot complex application, API, and integration issues.
• Participate in architecture and technical design discussions.
• Develop reusable services, components, APIs, and integration frameworks.
• Work across both Java and Microsoft technology environments as business needs require.
• Quickly learn and work with new SDKs, APIs, frameworks, and third-party platforms.
• Collaborate with architects, product owners, business analysts, QA, DevOps, and engineering teams.
• Conduct code reviews and promote engineering best practices.
• Mentor and provide technical guidance to internal developers.
• Conduct technical knowledge-transfer and training sessions.
• Support application modernization and technology transformation initiatives.
• Contribute to CI/CD, automated testing, deployment, and production support activities.

Java Primary

• 7 years of hands-on Java development experience.
• Strong knowledge of Java 8 , preferably Java 11/17/21.
• Strong Spring Framework / Spring Bootexperience.
• Experience developing enterprise applications and microservices.
• Strong understanding of object-oriented programming and design patterns.

.NET / C# Required or Strongly Preferred

• Strong hands-on experience with C# and .NET.
• Experience with .NET Core / modern .NET.
• Experience developing enterprise applications and APIs using .NET.
• Strong understanding of object-oriented programming and common design patterns.
• Experience working with ASP.NET Core Web API.
• Ability to understand and contribute to applications built on both Java and .NET platforms.
• Experience modernizing or integrating legacy .NET applications is a plus.

• Strong experience designing and developing REST APIs.
• Experience consuming and integrating with third-party APIs.
• Strong understanding of API authentication, authorization, security, error handling, and versioning.
• Experience with application-to-application and system integrations.
• Experience troubleshooting API and integration issues.
• Strong understanding of JSON and XML.
• Experience with API gateways and integration platforms is desirable.
• Experience with event-driven architecture and messaging is a plus.

• Experience with React, Angular, JavaScript, or TypeScript.
• Ability to work across front-end and back-end components.
• Experience integrating web applications with REST APIs.
• Understanding of modern web application architecture.
• Ability to move between Java/.NET backend services and front-end applications when required.

• Experience with AWS, Azure, or other cloud platforms.
• Experience with CI/CD pipelines.
• Experience with Git, Jenkins, GitHub Actions, Azure DevOps, or similar tools.
• Experience with Docker/Kubernetes is desirable.
• Exposure to Kafka, RabbitMQ, Azure Service Bus, or similar messaging technologies.
• Experience with infrastructure and application monitoring is a plus.

• Strong SQL skills.
• Experience with SQL Server and/or Oracle.
• Experience working with relational databases in enterprise applications.
• Understanding of ORM technologies such asHibernate/JPA or Entity Framework.

The successful candidate should:

• Demonstrate senior-level technical capability and ownership.
• Be comfortable working across Java and .NET technology stacks.
• Be able to understand complex enterprise applications quickly.
• Have strong problem-solving and analytical skills.
• Be comfortable learning new SDKs, APIs, frameworks, and systems.
• Be able to work across multiple applications rather than being limited to one system.
• Communicate technical concepts effectively with both technical and non-technical stakeholders.
• Be comfortable mentoring and training internal developers.
• Demonstrate strong collaboration and interpersonal skills.
• Take ownership of technical issues and drive them through resolution.

Experience in banking, credit unions, financial services, payments, lending, or other regulated industries is highly desirable.

Experience with:

• Banking applications
• Loan/lending systems
• Digital banking
• Payment platforms
• Customer/member applications
• Financial services APIs
• Security and regulatory requirements would be an advantage.