ZipRecruiter

Log In

1

Senior Mainframe Developer Jobs in Gaithersburg, MD

System One

Senior Mainframe Developer (COBOL)

Reston, VA · Remote

$83/hr

Senior Mainframe Developer (COBOL) Location: Primarily Remote Onsite Expectations: Monthly travel to Reston, VA for PI Planning Compensation: $83/HR Employment Type: W2 only About the Role We're ...

System One

Senior Mainframe Engineer

Merrifield, VA · Remote

Senior Mainframe Engineer Location: remote Pay rate: open to W2 and established 1099s Position type: multiyear contract We are currently seeking a Senior Mainframe Programmer/Support Analyst with a ...

TekCommands Inc

Sr Mainframe Developer / Support

Mclean, VA · On-site

$49.50 - $63.75/hr

Experience in mainframe systems Experience in Application Support Strong communication skills A minimum 8 - 10 years of systems analysis/application development experience Background in development ...

New

Navy Federal Credit Union

Senior Mainframe Engineer

Vienna, VA · On-site

$123K - $162K/yr

Experience with SMP/E maintenance and z/OS system programming concepts. * Familiarity with Ansible, REST APIs, and mainframe modernization technologies Additional Information Hours: * Monday - Friday ...

New

System One

.NET Mainframe Developer

Vienna, VA · Remote

$50.25 - $64.50/hr

Serve as a senior technical contributor responsible for translating business and platform ... Expertise in programming languages / standards / build tools including Java, XML, Open API, Maven ...

System One

.NET Mainframe Developer

Vienna, VA · Remote

$50.25 - $64.50/hr

Serve as a senior technical contributor responsible for translating business and platform ... Expertise in programming languages / standards / build tools including Java, XML, Open API, Maven ...

System One

.NET Mainframe Developer

Vienna, VA · Remote

$50.25 - $64.50/hr

Serve as a senior technical contributor responsible for translating business and platform ... Expertise in programming languages / standards / build tools including Java, XML, Open API, Maven ...

System One

.NET Mainframe Developer

Vienna, VA · Remote

$50.25 - $64.50/hr

Serve as a senior technical contributor responsible for translating business and platform ... Expertise in programming languages / standards / build tools including Java, XML, Open API, Maven ...

System One

.NET Mainframe Developer

Vienna, VA · Remote

$50.25 - $64.50/hr

Serve as a senior technical contributor responsible for translating business and platform ... Expertise in programming languages / standards / build tools including Java, XML, Open API, Maven ...

System One

.NET Mainframe Developer

Vienna, VA · Remote

$50.25 - $64.50/hr

Serve as a senior technical contributor responsible for translating business and platform ... Expertise in programming languages / standards / build tools including Java, XML, Open API, Maven ...

next page

Showing results 1-20

All JobsMainframe Developer JobsSenior Mainframe Developer JobsSenior Mainframe Developer Jobs in Gaithersburg, MD

Senior Mainframe Developer information

See Gaithersburg, MD salary details

$41

$62

$71

How much do senior mainframe developer jobs pay per hour?

As of Aug 1, 2026, the average hourly pay for senior mainframe developer in Gaithersburg, MD is $62.29, according to ZipRecruiter salary data. Most workers in this role earn between $58.46 and $68.03 per hour, depending on experience, location, and employer.

What are the key skills and qualifications needed to thrive as a Senior Mainframe Developer, and why are they important?

To thrive as a Senior Mainframe Developer, you need deep expertise in mainframe programming languages (like COBOL, JCL, and PL/I), systems analysis, and a strong understanding of legacy application architectures, typically supported by a degree in computer science or related experience. Familiarity with tools such as IBM z/OS, DB2, CICS, and version control systems is essential, along with relevant certifications like IBM Certified System Programmer. Excellent problem-solving, communication, and leadership skills help you collaborate effectively and mentor junior developers. These skills are crucial for maintaining mission-critical systems, ensuring reliability, and guiding modernization efforts in complex enterprise environments.

What are some common challenges faced by Senior Mainframe Developers when integrating legacy systems with modern technologies?

Senior Mainframe Developers often encounter challenges when integrating legacy mainframe systems with newer technologies such as cloud platforms, APIs, or microservices. These challenges include ensuring data consistency, maintaining system security, and minimizing downtime during migrations. Collaboration with cross-functional teams, such as infrastructure engineers and application developers, is key to developing seamless integration solutions. Staying up-to-date with modernization tools and best practices can help address these complexities and support the organization's digital transformation goals.

What are Senior Mainframe Developers?

Senior Mainframe Developers are experienced professionals who design, develop, and maintain mainframe systems—large-scale computers used by organizations for critical applications, bulk data processing, and enterprise resource planning. They are proficient in languages like COBOL, JCL, and Assembler, and often work with databases and transaction processing systems. Their responsibilities include troubleshooting system issues, optimizing performance, mentoring junior developers, and ensuring the reliability and security of mainframe operations.
What job categories do people searching Senior Mainframe Developer jobs in Gaithersburg, MD look for? The top searched job categories for Senior Mainframe Developer jobs in Gaithersburg, MD are:
What cities near Gaithersburg, MD are hiring for Senior Mainframe Developer jobs? Cities near Gaithersburg, MD with the most Senior Mainframe Developer job openings:
Senior Mainframe Developer jobs near you
Infographic showing various Senior Mainframe Developer job openings in Gaithersburg, MD as of July 2026, with employment types broken down into 83% Full Time, 5% Part Time, 1% Temporary, and 11% Contract. Highlights an 82% Physical, 5% Hybrid, and 13% Remote job distribution, with an average salary of $129,564 per year, or $62.3 per hour.

Senior Mainframe Developer (COBOL)

System One

Reston, VA • Remote

$83/hr

Contractor

Medical, Dental, Vision, Life, Retirement

Re-posted 14 days ago

Job description

Senior Mainframe Developer (COBOL) Location: Primarily Remote Onsite Expectations: Monthly travel to Reston, VA for PI Planning Compensation: $83/HR Employment Type: W2 only

About the Role We’re looking for a Senior Mainframe COBOL Developer to support and enhance large-scale enterprise systems. This role is ideal for someone who thrives in a mainframe environment, enjoys solving complex problems, and is open to evolving technologies. You’ll play a key role in maintaining critical applications, supporting high-volume systems, and contributing to modernization efforts where applicable.
Work Model
  • Primarily remote
  • Must live in the DMV area or nearby states (WV, DE, PA) OR be willing to relocate
  • Ability to travel to Reston, VA approximately once per month for PI Planning
What You’ll Do
  • Design, develop, test, and maintain mainframe applications using COBOL
  • Work across core mainframe tools including CICS, JCL, TSO/ISPF, and related utilities
  • Analyze business and technical requirements to develop scalable solutions
  • Support production systems, troubleshoot issues, and resolve critical defects
  • Perform code reviews, testing, and ensure adherence to quality standards
  • Collaborate with cross-functional teams to deliver reliable, high-performing systems
  • Participate in Agile ceremonies and PI Planning sessions
  • Identify opportunities to improve performance, stability, and maintainability
  • Mentor junior developers and contribute to team best practices
What You Bring Required Experience
  • 5–8 years of mainframe development experience
  • Strong expertise in:
    • COBOL
    • CICS
    • JCL
    • TSO/ISPF
    • Mainframe change management tools (e.g., ChangeMan, Topaz)
  • Experience supporting large-scale enterprise systems
  • Ability to analyze, debug, and work with existing legacy codebases
  • Experience in Agile/Scrum environments
  • Strong problem-solving and communication skills
  • Ability to work independently and as part of a distributed team
? Candidates with prior mainframe experience (even if from 1–3 years ago) are encouraged to apply if they’re confident returning to hands-on COBOL work
Nice to Have
  • Exposure to Java or modern integration technologies
  • Experience with web services (REST/SOA)
  • Familiarity with AWS or cloud concepts
  • Experience with DevOps / CI-CD pipelines
  • Healthcare domain experience (especially working with enrollment or benefits data)
  • Experience with Git / Bitbucket
Education
  • Bachelor’s degree in Computer Science, IT, or related field
  • OR equivalent experience (additional 4 years of relevant work)

System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.

System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.

#M-1 #LI-AJ1

Ref: #851-Rockville-S1