Senior ML Software Engineer

Worldpay (UK) Limited is seeking a Senior ML Software Engineer to help productionize machine learning for payment optimization. This role builds and operates backend and API services that turn ML models into reliable, scalable capabilities, with end-to-end responsibility for service performance and operational outcomes.

Working in a cross-functional agile team based in Cincinnati, OH (onsite), you will focus on shipping production-grade ML systems rather than model research, with SLO-driven reliability and continuous improvement across shared platform tooling.

What you’ll do

• Design, implement, and deploy software features, backend services, and APIs that operationalize ML models in production, emphasizing backend, API, and service engineering.
• Provide full technical ownership for existing and new production ML services in your area, ensuring technical investments align with business goals and engineering best practices.
• Steward service reliability and performance using SLO-driven approaches.
• Improve shared platform tooling and standards to increase developer velocity, reliability, and repeatable delivery across teams.
• Maintain and enhance automated CI/CD pipelines, testing frameworks, and monitoring/logging; own pre-release testing, rollouts, and release coordination.
• Participate in on-call rotations, lead incident response, conduct root cause analysis, and drive remediation for your product area.
• Offer technical guidance to engineers and data scientists, mentor teammates, and promote continuous improvement and knowledge sharing.

What you bring

• 5+ years as a software engineer, MLOps Engineer, or similar role, with hands-on production experience operating backend services or ML-backed APIs.
• Proven experience deploying ML models as production services, including API design and service integration.
• Strong Python skills and production service/backend engineering experience (ideally FastAPI/OpenAPI, Flask, Go, or Java).
• Production experience with containerization and orchestration (ideally Kubernetes such as EKS/OpenShift), plus Docker and IaC (ideally Terraform or Terraform Cloud).
• Experience owning CI/CD, monitoring/alerting, and on-call/incident response.
• Ability to monitor, troubleshoot, and optimize production ML systems, including latency, throughput, and availability.
• Excellent communication and cross-functional collaboration skills.
• Demonstrated ability to work independently, handle ambiguity, remove blockers, and deliver results with a strong sense of urgency.

Technologies you’ll work with

• Python
• FastAPI, OpenAPI
• Flask
• Go
• Java
• Kubernetes, EKS, OpenShift
• Docker
• Infrastructure as Code (IaC)
• Terraform, Terraform Cloud

Bonus if you have

• Experience with MLFlow / model versioning, SageMaker Pipelines, or Databricks.
• Familiarity with real-time, high-volume data products and low-latency data stores (e.g., DynamoDB).
• Automated testing and validation frameworks for models and services.
• Experience in regulated industries (e.g., PCI, HIPAA, SOC2), large companies, or mature engineering teams.
• Optional familiarity with LLM tooling / RAG.

Why this role

• Impact: Own high-profile ML-backed services that support customer-facing products and measurable business outcomes.
• Autonomy: Drive end-to-end technical ownership for your product area, shaping robust solutions and delivery practices in a fast-paced environment.
• Collaboration: Work with a cross-functional, high-performing team alongside engineering and product partners and industry experts.