Payment Processing Engineer Jobs in Hammond, IN (NOW HIRING)

About the Opportunity

We are seeking an experienced Payment Systems Engineer to help build and scale a modern enterprise payments platform supporting transactions across multiple customer channels, including in-store POS, e-commerce, mobile, kiosk, and call center environments.

This is a hands-on software engineering position for someone who enjoys solving complex transaction and integration challenges. You'll work with Product, Architecture, and other engineering teams to design reliable payment services, integrate with external payment providers, and develop capabilities that make payments secure, resilient, scalable, and seamless for customers.

The environment is primarily C# and .NET/.NET Core, with a strong emphasis on APIs, third-party integrations, transaction processing, system reliability, and production-ready engineering.

This is an excellent opportunity for a strong backend engineer who already has payments experience—or someone with solid transactional systems experience who wants to deepen their expertise in the payments space.

What You'll DoPayment Platform Development

• Design, build, maintain, and enhance payment services and APIs using C# and .NET/.NET Core.
• Develop backend services supporting payment transactions across POS, e-commerce, mobile, kiosk, and call center channels.
• Integrate with payment processors, gateways, acquiring banks, and third-party payment providers.
• Help build and enhance a payment abstraction layer designed to simplify integrations across multiple providers.
• Develop solutions supporting authorization, capture, settlement, refunds, chargebacks, and other core payment processes.
• Build scalable, maintainable services capable of supporting high-volume enterprise transaction environments.

Payment Integrations & Capabilities

• Design and maintain integrations using REST APIs, webhooks, and other payment protocols.
• Support both card-present and card-not-present transaction environments.
• Develop and enhance payment routing, retry logic, exception handling, and failover capabilities.
• Support integrations with digital wallets such as Apple Pay, Google Pay, and Samsung Pay.
• Contribute to mobile POS, in-app payments, hosted payment pages, and Text-to-Pay capabilities.
• Support traditional and emerging payment methods as the organization's payments ecosystem continues to evolve.

Reliability & Production Support

• Monitor and troubleshoot payment transactions and production issues.
• Investigate complex problems spanning internal applications, APIs, external payment providers, and transaction processing systems.
• Participate in incident response and root-cause analysis.
• Implement permanent fixes and improvements based on production incidents.
• Improve application performance, scalability, resiliency, and transaction success rates.
• Enhance system observability through effective logging, metrics, monitoring, and alerting.

Engineering & Collaboration

• Partner closely with Product, Architecture, and other engineering teams to translate business requirements into technical solutions.
• Participate in solution design, sprint planning, backlog grooming, and code reviews.
• Write clean, maintainable, secure, and well-tested code.
• Follow sound software engineering and secure-development practices appropriate for systems handling sensitive financial transactions.
• Contribute to the continuous improvement of engineering standards, development processes, tooling, and system architecture.

What We're Looking ForCore Qualifications

• Approximately 5–10 years of professional software engineering experience.
• Strong hands-on development experience with C# and .NET/.NET Core.
• Strong backend software engineering fundamentals.
• Experience building and consuming RESTful APIs.
• Hands-on experience integrating applications with external platforms, vendors, or third-party APIs.
• Experience working with relational databases such as SQL Server, PostgreSQL, or similar technologies.
• Understanding of secure coding practices and protecting sensitive data.
• Experience troubleshooting complex production systems and transaction-related issues.
• Strong analytical and problem-solving skills.
• Ability to communicate effectively and collaborate with engineering, product, architecture, and business stakeholders.

Payments Experience

Previous experience within payments, financial transactions, fintech, banking, retail commerce, POS, or a similarly transaction-intensive environment is highly valuable.

Relevant experience could include:

• Payment gateways and processors
• Acquiring banks
• POS systems
• Card-present and card-not-present transactions
• Authorization, capture, settlement, refunds, and chargebacks
• EMV
• Tokenization
• 3-D Secure / 3DS
• PCI-DSS
• Digital wallets
• Mobile payments
• ACH
• Buy Now, Pay Later
• Real-time payments

Candidates do not need experience with every payment technology listed above. We're particularly interested in engineers who understand transactional systems, third-party integrations, APIs, and the reliability requirements associated with business-critical payment platforms.

Additional Preferred Experience

Experience in one or more of the following areas would be beneficial:

• Event-driven architecture
• Kafka
• RabbitMQ
• Azure Service Bus
• Microsoft Azure, AWS, or Google Cloud
• Distributed systems
• High-volume transaction processing
• API-based integration architectures
• Monitoring and observability
• Agile/Scrum development
• Jira or Azure DevOps

What Makes Someone Successful Here

The strongest candidate will be more than someone who can simply write C# code.

You'll be comfortable tracing a transaction across multiple systems, identifying where and why something failed, understanding how external providers interact with internal applications, and designing solutions that remain reliable when systems don't behave exactly as expected.

You'll enjoy working on systems where availability, security, data integrity, resiliency, and transaction success matter.

Just as importantly, you'll be comfortable operating in a collaborative enterprise environment where payments touch numerous applications, customer experiences, business teams, and external technology partners.

Why Consider This Opportunity?

Payments sit at the center of the customer experience, and this role provides an opportunity to directly influence how a large enterprise handles transactions across multiple channels.

Rather than maintaining a single payment integration, you'll contribute to a broader payments platform designed to support multiple providers, payment methods, and customer experiences.

For an experienced backend engineer, this is an opportunity to combine C#/.NET engineering, APIs, distributed systems, integrations, and payments technology while helping build an increasingly modern and scalable enterprise payments architecture.