Senior Software Engineer - Payment Processing

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Software Engineer - Payment Processing based in Brazil.

We are seeking an experienced Senior Software Engineer to help modernize and scale a critical payment processing platform. In this role, you will tackle complex engineering challenges involving transaction tracking, financial reconciliation, fraud detection, and payment operations. You will design and implement automated solutions to replace manual processes while improving system reliability, security, and performance. Working across multiple integrations and interconnected platforms, you will help build a more unified and scalable payments architecture. You will collaborate with experienced engineering teams to address technical debt and strengthen core transaction-processing capabilities. This is an opportunity to make a significant impact on a growing payments ecosystem within a collaborative, remote-first environment.

Accountabilities:

• Design and implement automated, end-to-end transaction lifecycle tracking to replace existing manual reconciliation processes.
• Develop and enhance payment processing capabilities, including automated reconciliation, fraud detection, chargeback management, and other payment-related functions.
• Work across two parallel versions of the payment processing engine and their respective third-party processor integrations to identify and resolve inconsistencies, mismatches, and reconciliation gaps.
• Collaborate with the Storefront engineering team to improve data accessibility and establish the integrations required to close reconciliation gaps.
• Strengthen system reliability, maintainability, and scalability, ensuring the stability of critical payment flows as transaction volumes increase.
• Contribute to the design and development of a shared payments architecture connecting the payment processing engine, storefront, and events platform.
• Navigate complex, undocumented, multi-repository codebases using AI-assisted development tools such as Claude Code, Codex, or equivalent solutions.
• Make independent backend architecture decisions, evaluating service boundaries, data models, and system design trade-offs.
• Implement robust testing, monitoring, and observability practices to improve system quality and operational performance.
• Collaborate with engineering stakeholders to modernize legacy components and support the long-term evolution of the payments platform.

Requirements:

• 8+ years of professional software engineering experience, with strong expertise in backend development.

• Previous experience working with financial reconciliation, ledger systems, fraud detection, transaction processing, or other payment-related technologies.

• Hands-on knowledge of PCI-DSS compliance requirements, particularly as they apply to payment processing and financial reconciliation.

• Bachelor's degree in Computer Science, Engineering, or a related field, or equivalent professional experience.

• Proven ability to work with large, complex, non-microservices codebases spanning multiple repositories and legacy system architectures.

• Strong analytical and problem-solving skills, including the ability to trace and understand data flows across disconnected systems.

• Experience independently making backend architecture decisions and evaluating technical trade-offs.

• Hands-on experience integrating third-party payment processors, ideally involving multiple integration versions running simultaneously.

• Strong backend engineering fundamentals, preferably with .NET and SQL Server, or the ability to quickly become proficient in this technology stack.

• Solid understanding of relational database design and operations, including schema modeling, query optimization, and database locking behavior under production workloads.

• Experience deploying, operating, and troubleshooting production services in cloud environments, preferably Microsoft Azure.

• Demonstrated proficiency in at least one programming language, ideally .NET, Java, or Python.

• Experience with observability and monitoring platforms such as Datadog, New Relic, Honeycomb, or comparable tools.

• Extensive experience with automated testing frameworks and software quality practices.

• Practical proficiency with AI-assisted development tools such as Claude Code, Codex, or equivalent solutions.

• Strong communication and collaboration skills, with the ability to work independently in complex technical environments.

• Nice to have:

  • Advanced hands-on experience with .NET or Java.
  • Deep expertise in Microsoft Azure and its cloud services.
  • Specific experience developing financial reconciliation, ledger, fraud detection, chargeback management, or payment operations systems.
  • Previous experience consolidating, migrating, or modernizing two parallel versions of the same platform.
  • Background in payments or fintech, particularly within high-volume transaction processing environments.

  Benefits:

  • 100% remote work opportunity within Latin America, subject to employment eligibility and residency requirements.
  • Contract-based engagement.
  • Opportunity to contribute to the modernization of a business-critical payment processing platform.
  • Exposure to complex financial systems, payment integrations, fraud detection, and reconciliation technologies.
  • Collaboration with experienced engineering professionals across distributed international teams.
  • Opportunity to influence backend architecture, technical strategy, and long-term platform scalability.
  • Professional development through challenging projects involving cloud infrastructure, modern engineering practices, and AI-assisted development tools.