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Java Software Engineer Jobs in O Fallon, MO (NOW HIRING)

Artius Solutions

Lead Java Engineer

Saint Louis, MO · On-site

$140K - $150K/yr

Experience delivering high-quality software in regulated or large-scale enterprise domains. * Active involvement in tech communities, workshops, or mentoring engineers. Must-Have Technologies * Java ...

Mastercard, Inc.

Senior Software Engineer

O Fallon, MO · On-site

$114K - $151K/yr

The ideal candidate brings strong software engineering fundamentals, hands-on Java development experience, and a quality-first mindset, with the ability to build automation frameworks, contribute to ...

MasterCard

Senior Software Engineer

O Fallon, MO · On-site

$114K - $151K/yr

The ideal candidate brings strong software engineering fundamentals, hands-on Java development experience, and a quality-first mindset, with the ability to build automation frameworks, contribute to ...

MasterCard

Software Engineer II

O Fallon, MO · On-site

Title and Summary Software Engineer II Overview The Mastercard Authentication Program owns how ... Design, develop, and own Java-based backend services and REST APIs in a distributed architecture.

Ask IT consulting

JAVA Engineer

Saint Louis, MO · On-site

$50.25 - $69/hr

... software design and development and should be comfortable in a Linux shell Experience with build systems such as: Ant or Maven PREFERRED EXPERIENCE Project experience with JPA Project experience with ...

MasterCard

Software Engineer II

O Fallon, MO · On-site

Our patented Java-based platform processes billions of transactions per month in tens of ... MasterCard software engineering teams leverage Agile development principles, advanced development ...

ACI Infotech

Java Developer

Lake Saint Louis, MO · On-site

$48.25 - $62.50/hr

... software engineer will have: Bachelors or Masters degree, preferably in Computer Science, Computer Engineering or other technical (STEM) field or an equivalent combination of education and experience ...

Mastercard, Inc.

Software Engineer II

O Fallon, MO · On-site

As a Software Engineer II, you will contribute to building scalable backend services using Java/Spring and modern user interfaces using Angular and Node.js within a distributed architecture. You will ...

The Giant Bullseye

Senior Java Engineer

Saint Louis, MO · On-site

$55.75 - $71/hr

Overview We are looking for a highly skilled Senior Java Engineer to design, develop, and maintain ... quality software solutions * Participate in code reviews, performance optimization, and ...

CACI

Software Engineer

Saint Louis, MO · On-site

Engineering Time Type: Full time Minimum Clearance Required to Start: TS/SCI with Polygraph ... Develop, test, and maintain software applications using Java and/or Python. Design and implement ...

MasterCard

Senior Software Engineer

O Fallon, MO · On-site

$114K - $151K/yr

About the Role As a Java Site Reliability Engineer (SRE) within the Mastercard Send team, you will ... You will combine strong software engineering expertise with operational excellence practices to ...

CACI

Software Engineer

Saint Louis, MO · On-site

Engineering Time Type: Full time Minimum Clearance Required to Start: TS/SCI with Polygraph ... Develop, test, and maintain software applications using Java and/or Python. Design and implement ...

Mastercard

Software Engineer II

O Fallon, MO · On-site

$91K - $124K/yr

Our patented Java-based platform processes billions of transactions per month in tens of ... MasterCard software engineering teams leverage Agile development principles, advanced development ...

Equifax, Inc.

Senior Software Engineer

Saint Louis, MO · On-site

$119K - $157K/yr

Bachelor's degree or equivalent experience * 5+ years of software engineering experience * 5+ years experience writing, debugging, and troubleshooting code in mainstream Java, SpringBoot, TypeScript ...

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Java Software Engineer information

See O Fallon, MO salary details

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How much do java software engineer jobs pay per hour?

As of Sep 9, 2026, the average hourly pay for java software engineer in O'Fallon, MO is $56.50, according to ZipRecruiter salary data. Most workers in this role earn between $46.54 and $63.85 per hour, depending on experience, location, and employer.

What does a Java software engineer do?

A Java software engineer designs and develops computer applications using the Java programming language. In this job, you work with web developers and other software engineers to integrate java software into online platforms or other types of computer software. You are present for the entire development lifecycle, from design through quality testing. Your other duties may include documenting the programming code for other users or developers and writing reports to management or department heads. Java engineers work in large teams, so you must be able to collaborate with many people to complete a project.

What does a Java software engineer do?

A Java Software Engineer is responsible for designing, developing, and maintaining software applications using the Java programming language. They work on building efficient, scalable, and robust systems, often collaborating with other developers, testers, and stakeholders. Their tasks can include writing code, debugging, testing, and optimizing Java applications for various platforms, such as web, mobile, or enterprise environments. Java Software Engineers also help ensure that software solutions meet client or business requirements and adhere to industry best practices.

What are some typical challenges Java software engineers face when working on large-scale enterprise applications?

Java Software Engineers working on large-scale enterprise applications often encounter challenges such as managing complex codebases, ensuring high performance under heavy loads, and maintaining backward compatibility during system upgrades. Collaborating with cross-functional teams, like QA and DevOps, to streamline deployments and resolve integration issues is common. Additionally, keeping up with evolving frameworks and best practices is important for maintaining code quality and system reliability.

What are the key skills and qualifications needed to thrive as a Java software engineer, and why are they important?

To thrive as a Java Software Engineer, you need strong programming skills in Java, a solid understanding of object-oriented design, and typically a degree in computer science or a related field. Familiarity with development tools such as Eclipse or IntelliJ IDEA, version control systems like Git, and frameworks such as Spring or Hibernate is often required. Analytical thinking, problem-solving abilities, and effective teamwork distinguish high-performing individuals in this role. These skills ensure the efficient design, development, and maintenance of robust software applications in collaborative and dynamic technical environments.

What is the difference between Java Software Engineer vs Java Developer?

AspectJava Software EngineerJava Developer
Required CredentialsBachelor's in Computer Science, Java certificationsBachelor's in Computer Science, Java certifications
Work EnvironmentDesigning, developing, and testing Java applicationsWriting, debugging, and maintaining Java code
Employer & Industry UsageTech companies, software firms, enterprise solutionsStartups, software companies, freelance projects
Common Search & ComparisonOften compared for roles involving system design and architectureFocused on coding and implementation tasks

While both roles require similar skills and certifications, Java Software Engineers typically focus on designing and architecting Java applications, whereas Java Developers primarily concentrate on coding and maintaining Java programs. The choice depends on the project scope and career focus.

More about Java Software Engineer jobs

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The top searched job categories for Java Software Engineer jobs in O'Fallon, MO are:

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Cities near O'Fallon, MO with the most Java Software Engineer job openings:

Java Software Engineer jobs near you
Infographic showing various Java Software Engineer job openings in O'Fallon, MO as of August 2026, with employment types broken down into 82% Full Time, 14% Part Time, and 4% Contract. Highlights an 85% Physical, 4% Hybrid, and 11% Remote job distribution, with an average salary of $117,521 per year, or $56.5 per hour.

Lead Java Engineer

Saint Louis, MO • On-site

Artius Solutions
Recruiting and Staffing Services • 11 - 50 employees
Learn more about Artius Solutionsexternal

$140K - $150K/yr

Full-time

Medical, Dental, Vision, Retirement, PTO

Re-posted 24 days ago

Job description

Lead Java Engineer

Location: Saint Louis, Missouri (On-Site/Hybrid/Remote – specify as needed)
Employment Type: Full-Time, Direct Hire

About the Role

We are seeking an accomplished Lead Java Engineer who will drive the end-to-end design, development, and delivery of modern, scalable web and cloud-native applications. This role calls for a hands-on leader who combines strong architectural vision, technical excellence, and a collaborative spirit to build robust enterprise platforms.

You will take ownership of platform architecture, drive technology best practices, and mentor engineering teams. Your work will directly influence project direction, enable delivery of high-quality code, and build a culture of technical excellence.

Responsibilities

  • Lead the architecture, design, development, and testing of web and cloud-native applications in a cross-functional Agile team.

  • Guide end-to-end technical delivery, including architectural assessments and solution design for enterprise platforms.

  • Break down epics/features, define technical strategies, and maintain architectural integrity across the product.

  • Mentor and support junior engineers; take part in hiring, onboarding, and technical knowledge sharing.

  • Champion best development practices: branching strategies, code reviews, library management, robust logging, and error handling.

  • Enforce and document coding guidelines, code scanning profiles, and technical standards to ensure maintainability and reduce technical debt.

  • Advocate for and practice Test-Driven Development (TDD) and automated test coverage (unit, integration, functional, contract).

  • Design and implement microservices using Spring Boot, Spring WebFlux, and modern design patterns (hexagonal architecture, DDD).

  • Build, optimize, and maintain RESTful APIs and implement asynchronous inter-service communication using Kafka.

  • Oversee database schema design, data migration, query optimization, and secure, reliable interactions with relational and NoSQL databases (Oracle, AWS RDS, DynamoDB).

  • Implement and support cloud infrastructure (AWS) using services like EKS, EC2, S3, RDS, SQS, SNS, Lambda, ECS, and Docker/Kubernetes containers.

  • Stay current with industry trends, new technologies, and best practices; contribute to internal tech talks and workshops.

Requirements

  • 7+ years hands-on experience in microservices-based, cloud-native Java application development within enterprise environments.

  • 3+ years of technical leadership/lead engineer experience in agile teams.

  • Expertise in Java (JDK 8 or higher; Java 21 preferred): including lambda expressions, Stream API, CompletableFuture, Virtual Threads, and concurrency APIs.

  • Proven ability with Spring Boot, Spring WebFlux, JPA, Spring Security, Actuator, Kafka, Redis.

  • AWS Cloud: 2+ years hands-on using EKS, EC2, S3, RDS, SQS, SNS, DynamoDB, Lambda.

  • Practical, hands-on experience with RESTful API design and hexagonal architecture.

  • Advanced skills in relational databases (Oracle or AWS RDS), schema design, and data migrations.

  • Proficiency with container and serverless architectures (Docker, Kubernetes, AWS Lambda/ECS).

  • Strong in TDD/DDD, using frameworks such as JUnit, Cypress, WireMock, PowerMock, ArchUnit.

  • Familiar with CI/CD tools and pipelines (DevOps mindset), application lifecycle management tools (e.g., Jira).

  • Strong verbal and written communication, consultant-level client-facing skills, and self-starter mindset.

Preferred Qualifications

  • Prior experience in end-to-end architectural ownership of cloud or enterprise web platforms.

  • Experience delivering high-quality software in regulated or large-scale enterprise domains.

  • Active involvement in tech communities, workshops, or mentoring engineers.

Must-Have Technologies

  • Java (JDK 8+)

  • Spring Boot

  • Microservices

  • Kafka

  • AWS

  • Relational databases

  • Experience with multiple testing strategies (unit, integration, functional, contract tests)

Benefits

  • Competitive salary and performance-based bonus

  • Comprehensive health, dental, and vision coverage

  • 401(k) with match

  • Flexible PTO policy

  • Opportunities for technical and career growth

  • Engaging, collaborative, and innovative team culture

To apply:
Submit your updated resume detailing relevant experience in Java, cloud platforms, AWS, microservices, and leadership. Only candidates with strong hands-on and leadership experience in modern Java stacks will be considered.

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