Sr. Java Developer

Mavensoft Technologies LLC; Denver (CO); Hybrid; USD 96,000 - 165,000; Full time

Job summary

Mavensoft Technologies LLC is seeking a Senior Java Developer contractor in Denver (Hybrid). You will design, develop, and maintain Java-based web applications and backend services, leveraging Spring Boot, REST APIs, and AWS services.

The role emphasizes hands-on development, CI/CD practices, and collaboration with stakeholders. The ideal candidate will be proficient with Java 21+, JSON, HTML/CSS/JS, and GitLab workflows, while contributing to Terraform-managed infrastructure and code quality

Qualifications

• Strong professional experience developing Java applications.
• Experience with Java 21 or newer Java SDK versions.
• Solid experience with Spring Boot and Spring-based application development.
• Experience designing, building, and consuming REST APIs.
• Strong working knowledge of JSON and API integration patterns.
• Familiarity with HTML, CSS, and JavaScript.
• Experience with Git-based source control, preferably GitLab.
• Experience with CI/CD pipelines, preferably GitLab CI/CD.
• Practical experience deploying or supporting applications in AWS.
• Ability to work independently, communicate clearly, and deliver high-quality work in a contractor capacity.

Responsibilities

• Design, develop, test, and maintain Java-based applications using Java SDK 21.
• Build and enhance applications using Spring Boot and the Spring Framework.
• Develop and maintain REST APIs and JSON-based integrations.
• Support web applications using Thymeleaf, HTML, CSS, and JavaScript.
• Work with AWS services including ECS, API Gateway, and DynamoDB.
• Contribute to source control and development workflows using GitLab.
• Build, maintain, and troubleshoot GitLab CI/CD pipelines.
• Participate in application architecture, implementation decisions, code reviews, and deployment practices.
• Support infrastructure-as-code efforts, particularly using Terraform.
• Use IntelliJ IDEA as the primary development environment.
• Apply sound software engineering practices including maintainable code, testing, documentation, and operational awareness.
• Leverage AI-assisted coding tools where appropriate to improve productivity and code quality.

Skills

Java

Spring Boot

REST APIs

JSON

HTML/CSS/JS

GitLab

CI/CD

AWS

Contractor mindset

Communication

Tools

Terraform

Job description

Title: Sr. Java Developer

Location: Denver, CO – Hybrid ,MST ( Candidate Must Be Local )
Hybrid, 1 day On-site on Tuesdays. Remote work rest of days
Duration: 7 Months – W2 Contract

Job Description

Our Client is seeking an experienced Java Developer Contractor to support the design, development, and maintenance of web applications, backend services, and cloud-based solutions.

The ideal candidate will be comfortable working across the Java/Spring ecosystem, building REST APIs, integrating with AWS services, and contributing to modern CI/CD-driven development workflows. The candidate should be hands‑on, pragmatic, able to work independently, and comfortable collaborating with technical and business stakeholders.

Responsibilities

• Design, develop, test, and maintain Java-based applications using Java SDK 21.
• Build and enhance applications using Spring Boot and the Spring Framework.
• Develop and maintain REST APIs and JSON-based integrations.
• Support web applications using Thymeleaf, HTML, CSS, and JavaScript.
• Work with AWS services including ECS, API Gateway, and DynamoDB.
• Contribute to source control and development workflows using GitLab.
• Build, maintain, and troubleshoot GitLab CI/CD pipelines.
• Participate in application architecture, implementation decisions, code reviews, and deployment practices.
• Support infrastructure-as-code efforts, particularly using Terraform.
• Use IntelliJ IDEA as the primary development environment.
• Apply sound software engineering practices including maintainable code, testing, documentation, and operational awareness.
• Leverage AI-assisted coding tools where appropriate to improve productivity and code quality.

Required Qualifications

• Strong professional experience developing applications with Java.
• Experience with Java 21 or recent versions of the Java SDK.
• Solid experience with Spring Boot and Spring-based application development.
• Experience designing, building, and consuming REST APIs.
• Strong working knowledge of JSON and API integration patterns.
• Familiarity with HTML, CSS, and JavaScript.
• Experience with Git-based source control, preferably GitLab.
• Experience with CI/CD pipelines, preferably GitLab CI/CD.
• Practical experience developing, deploying, or supporting applications in AWS.
• Ability to work independently, communicate clearly, and deliver high-quality work in a contractor capacity.

Preferred Qualifications

• Experience with Thymeleaf.
• Hands‑on experience with Amazon ECS, API Gateway, and DynamoDB.
• Familiarity with Terraform or other infrastructure-as-code tools.
• Professional experience using IntelliJ IDEA.
• Familiarity with AI-assisted development tools such as Claude Code, GitHub Copilot, Cursor, or similar tools.
• Experience troubleshooting cloud deployments, application logs, build pipelines, and environment-related issues.
• Understanding of secure coding practices and cloud application security concepts.