Freelance Mainframe Network Engineer Jobs in Boston, MA

At BBH, Partnership is more than a form of ownership-it's our approach to business and relationships. We know that supporting your professional and personal goals is the best way to help our clients and advance our business. We take that responsibility seriously. With a 200-year legacy and a shared passion for what's next, this is the right place to build a fulfilling career.
Mainframe Programmer - SWIFT & Financial Messaging Platform
Brown Brothers Harriman is seeking an experienced Mainframe Programmer to join our Data Movement Technology team. This role is ideal for a highly skilled mainframe professional with extensive experience in enterprise transaction processing, COBOL development, DB2, CICS, z/OS, and IBM middleware. While knowledge of SWIFT messaging is beneficial, the primary focus of this position is the support, maintenance, and optimization of mission-critical mainframe applications that support financial messaging and payment processing operations.
The successful candidate will play a key role in the full software development lifecycle, including analysis, design, coding, testing, implementation, troubleshooting, performance tuning, and production support within a high-availability mainframe environment.
The successful candidate will play a key role in the maintenance, support, and operational stability of business-critical mainframe applications. Responsibilities will include incident analysis and resolution, production/testing support, performance tuning, monitoring system health, application upgrades, troubleshooting, and ensuring the reliability and availability of high-volume financial transaction processing systems within a 24x7 environment. Limited development work may be required to support enhancements, defect remediation, and regulatory or business-driven changes.
In addition this position also provides an excellent opportunity to expand technical expertise by gaining hands-on experience with the SWIFT network, financial messaging technologies, and distributed platforms that support BBH's global payment and data movement infrastructure.
Key Responsibilities

• Support and maintain critical mainframe applications that support financial transaction processing and messaging.
• Provide application support using COBOL, JCL, DB2, MQ, CICS and z/OS and technologies.
• Troubleshoot production issues, perform root-cause analysis, and ensure system stability.
• Support, install and administer IBM Financial Transaction Manager (FTM).
• Monitor application and system performance and implement improvements as needed.
• Collaborate with operations, infrastructure, database, network, and support teams.
• Participate in code reviews and support application enhancements and defect fixes.
• Create and maintain technical and operational documentation.
• Follow change management and release processes using tools such as ChangeMan.
• Participate in an on-call rotation to support high availability requirements.
• Support Business Continuity Planning (BCP) and Disaster Recovery (DR) activities.
• Support SWIFT Customer Security Programme (CSP) requirements.
• Contribute to platform reliability, operational efficiency, and modernization initiatives.

Required Qualifications

• 10+ years of hands-on mainframe development and support experience in large-scale enterprise environments.
• Strong expertise in:
  • COBOL
  • JCL
  • DB2
  • CICS
  • MQ
  • z/OS (MVS)
  • ChangeMan or equivalent source control/change management tools
• Experience installing, configuring, and supporting IBM software products.
• Experience with IBM Financial Transaction Manager (FTM) or similar financial transaction processing platforms.
• Strong SQL, and performance tuning experience within DB2 environments.
• Experience troubleshooting complex production issues and conducting root-cause analysis.
• Experience with system monitoring and application performance optimization.
• Excellent verbal and written communication skills.
• Ability to work effectively in a fast-paced, high-availability financial services environment.
• Strong analytical and problem-solving skills with a focus on delivering reliable, scalable solutions.

Preferred Qualifications

• Experience supporting financial services transaction processing systems.
• Familiarity with SWIFT messaging standards and infrastructure.
• Experience with IBM Integration Bus (IIB) or related integration technologies.
• Knowledge of payment processing, settlements, or banking operations.
• Bachelor's degree in Computer Science, Information Technology, or a related discipline (preferred but not required).

Ideal Candidate Profile
You are a seasoned Mainframe Engineer who thrives in a mission-critical financial environment. You bring deep expertise in COBOL, DB2, MQ, CICS, JCL, and z/OS, enjoy solving complex technical challenges, and have experience supporting high-volume transaction processing platforms. SWIFT knowledge is valuable, but your primary strength is the support, maintenance, and optimization of mission-critical mainframe financial messaging applications.
Salary Range
MA: $110,000 - $160,000 base salary + annual target bonus
BBH and its affiliates' compensation program includes base salary, discretionary bonuses, and profit-sharing. The anticipated base salary range(s) shown above are only for the indicated location(s) and may differ in other locations due to cost of living and labor considerations. Base salaries may vary based on factors such as skill, experience and qualification for the role. BBH's total rewards package recognizes your contributions with more than just a paycheck-providing you with benefits that enhance your experience at BBH from long-term savings, healthcare, and income protection to professional development opportunities and time off, our programs support your overall well-being.
We value diverse experiences. We value diverse experiences and transferrable skillsets. If your career hasn't followed a traditional path, includes alternative experiences, or doesn't meet every qualification or skill listed in the job description, please do go ahead and apply.
About BBH:
Brown Brothers Harriman (BBH) is a premier global financial services firm, known for premium service, specialist expertise, technology solutions and partnership approach to client management. Across Investor Services and Capital Partners, we work with an enviable roster of sophisticated clients who make BBH their first call when they are tackling their hardest challenges. Delivering for our clients and each other energizes us.
We believe that how we do our work is just as important as what we do. We are relentless problem solvers who know our best ideas come from collective debate and development-so we are never possessive about our ideas. Every day we come together as a diverse community of smart and caring people to deliver exceptional service and expert advice-creating success that lasts. No matter where you sit in the organization, everyone is empowered to contribute their ideas. BBHers can pick up the phone and call any colleague, and they are happy to help. Expanding your impact beyond your daily role is part of how we operate as trusted partners to one another.
We believe stability is a competitive advantage, but being stable means having the knowledge, skill, and discipline to evolve, often-pushing the boundaries of innovation. As a private partnership, every investment we make is in the relationships, technologies, products and development we believe are in the long-term interests of our clients and our people. Our long-tenured leaders are experts in their areas and are actively involved in the day-to day business, taking the time to provide guidance and mentoring to build the next generation of BBHers. Because we know, our success begins with yours.
Go to BBH.com to learn more about our rewards and benefits, philanthropy, approach to sustainability or how we support you to thrive personally, physically and financially.
We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, gender, national origin, age, genetic information, creed, marital status, sexual orientation, gender identity, disability status, protected veteran status, or any other protected status under federal, state or local law.