Python / PySpark (Mainframe Modernization)

Python / PySpark (Mainframe Modernization)

Location: San Francisco, California (Onsite)

Employment Type: Contract

Duration: 12 months

Role Overview

We are seeking a Senior Software Engineer with backend expertise to join a Scrum-based delivery team modernizing a mission-critical financial system. This role is heavily backend-focused, with an emphasis on Python and PySpark, while also contributing to frontend development using React and Angular as needed. This individual will serve as a technical subject matter expert, guiding a team that is upskilling from mainframe technologies. The position requires mentorship, technical guidance, and communication skills to work with Product Owners, Lines of Business, and Operations teams.

Key Responsibilities

• Design, develop, and modernize backend services to replace legacy mainframe functionality on a distributed platform.
• Build and maintain data ingestion, validation, and transformation pipelines using Python and PySpark.
• Develop and support APIs using FastAPI and/or Flask.
• Collaborate within a Scrum team, partnering closely with Product Owners and stakeholders.
• Act as a Python SME, mentoring engineers transitioning from mainframe technologies.
• Contribute to frontend development using React and Angular when required.
• Ensure data accuracy and integrity for financial feeds flowing into general ledger systems.
• Participate in technical design discussions, code reviews, and architecture decisions.
• Communicate effectively through documentation, presentations, and stakeholder discussions.
• Support CI/CD pipelines and cloud-native deployments using containerized platforms.

Required Qualifications

• 7+ years of relevant professional software engineering experience.
• Strong expertise in Python, with production experience using PySpark.
• Backend experience with FastAPI and/or Flask.
• Frontend experience with React and/or Angular.
• Experience with SQL Server and/or Exadata.
• Hands-on experience with Kafka or other streaming platforms.
• Experience working in Agile / Scrum delivery models.
• Strong communication, presentation, and stakeholder engagement skills.
• Ability to guide and mentor other engineers as a senior technical contributor.

Preferred Qualifications

• Agentic AI frameworks: LangGraph, LangChain, A2A.
• Programming Languages: Java, Scala, SQL, HiveQL.
• Big Data Technologies: Hadoop, Spark, HDFS, Hive, Cloudera, Hortonworks.
• Cloud Platforms: AWS (Glue, Lambda, Redshift, S3, CloudWatch).
• ETL / ELT Tools: AWS Glue, PySpark, Databricks.
• Data Integration & Migration: Hadoop ecosystems, Kafka, real-time streaming, data lakes.
• Data Modeling: dimensional models, structured and unstructured data processing.
• CI/CD & Automation: GitHub Actions, Azure DevOps, Jenkins, Git, Autosys, Airflow.
• Containerization & Orchestration: Kubernetes.
• Experience in financial institutions or enterprise accounting environments.

EEO Employer. Apex Systems is an equal opportunity employer. We do not discriminate or allow discrimination on the basis of race, color, religion, creed, sex (including pregnancy, childbirth, breastfeeding, or related medical conditions), age, sexual orientation, gender identity, national origin, ancestry, citizenship, genetic information, registered domestic partner status, marital status, disability, status as a crime victim, protected veteran status, political affiliation, union membership, or any other characteristic protected by law. Apex will consider qualified applicants with criminal histories in a manner consistent with the requirements of applicable law.

Apex uses a virtual recruiter as part of the application process. Click here for more details.

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Everforth Apex is a world-class IT services company that serves thousands of clients across the globe. When you join Everforth Apex, you become part of a team that values innovation, collaboration, and continuous learning. We offer quality career resources, training, certifications, development opportunities, and a comprehensive benefits package. Our commitment to excellence is reflected in many awards, including ClearlyRateds Best of Staffing® in Talent Satisfaction in the United States and Great Place to Work® in the United Kingdom and Mexico.

Everforth Apex uses a virtual recruiter as part of the application process. Click here for more details. By applying for this job, you agree to receive calls, AI-generated calls, text messages, or emails from Everforth Apex and its affiliates, and contracted partners. Frequency varies for text messages. Message and data rates may apply. Carriers are not liable for delayed or undelivered messages. You can reply STOP to cancel and HELP for help. You can access our privacy policy at

Everforth Apex Benefits Overview: Everforth Apex offers a range of supplemental benefits, including medical, dental, vision, life, disability, and other insurance plans that offer an optional layer of financial protection. We offer an ESPP (employee stock purchase program) and a 401K program which allows you to contribute typically within 30 days of starting, with a company match after 12 months of tenure. Everforth Apex also offers a HSA (Health Savings Account on the HDHP plan), a SupportLinc Employee Assistance Program (EAP) with up to 8 free counseling sessions, a corporate discount savings program and other discounts. In terms of professional development, Everforth Apex hosts an on-demand training program, provides access to certification prep and a library of technical and leadership courses/books/seminars once you have 6+ months of tenure, and certification discounts and other perks to associations that include CompTIA and IIBA. Everforth Apex has a dedicated customer service team for our Consultants that can address questions around benefits and other resources, as well as a certified Career Coach. You can access a full list of our benefits, programs, support teams and resources within our 'Welcome Packet' as well, which an Everforth Apex team member can provide.

Everforth Apex Systems is an equal opportunity employer. We do not discriminate or allow discrimination on the basis of race, color, religion, creed, sex (including pregnancy, childbirth, breastfeeding, or related medical conditions), age, sexual orientation, gender identity, national origin, ancestry, citizenship, genetic information, registered domestic partner status, marital status, disability, status as a crime victim, protected veteran status, political affiliation, union membership, or any other characteristic protected by law. Everforth Apex will consider qualified applicants with criminal histories in a manner consistent with the requirements of applicable law.

If you require an accommodation under the Americans with Disabilities Act to participate in an interview with a virtual recruiter or to use our website for a search or application, please contact our Benefits Department at [email protected] or View phone number on click.appcast.io. Please note that this contact information is strictly to be used for medical ADA accommodations and that no other inquiries will be answered.

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