Software Engineer, Payments (.NET / Vue.js)

Software Engineer, Payments (.NET / Vue.js)

Job Summary

The individual in this role will design, build, test, and maintain features for our payments platform, including the web-based merchant portal and checkout experiences, backend services and APIs, and integrations with physical payment terminals and payment processors. The Software Engineer works across the stack (.NET 8, Vue.js, and Azure Table and Blob Storage) to deliver reliable, secure, and well-tested software that accurately moves money. Competitive candidates have [3+] years of professional software development experience, ideally on transaction-processing or other high-reliability systems.

Duties and Responsibilities

• Translate business requirements and payment processes (authorization, capture, void, refund, settlement, reconciliation) into technical designs and working software.
• Design, develop, and maintain backend services and APIs using C# and .NET 8, including payment, webhook, and reporting endpoints.
• Build and maintain front-end features in Vue.js for the merchant portal, hosted checkout, and admin tools, with attention to usability, accessibility, and cross-browser behavior.
• Design and implement data models and access patterns in Azure Table Storage and Blob Storage, including partition and row key design, query performance, and data retention.
• Build integrations with payment processors, gateways, and terminal software, handling asynchronous responses, timeouts, retries, and error conditions gracefully.
• Design for idempotency, data consistency, and fault tolerance so that duplicate requests, network failures, and partial failures never result in incorrect charges or lost transactions.
• Support terminal-related development, including communication between terminals and the platform, offline or store-and-forward scenarios, and firmware and application update workflows.
• Write clean, maintainable, and well-documented code, and participate in code reviews, design discussions, and architecture decisions.
• Write unit, integration, and automated tests, and partner with QA to ensure features are testable and thoroughly validated before release.
• Investigate and resolve defects, including issues escalated by the support engineering team, using logs, monitoring, and transaction data to identify root causes.
• Collaborate with the support engineering team to improve diagnostics, logging, and internal tooling so that transaction lookups and issue investigations are faster and more reliable.
• Follow secure coding practices and PCI DSS requirements, including protection of cardholder data, encryption, tokenization, secrets management, and access controls.
• Support certification and compliance efforts, such as card brand, EMV, acquirer/processor, and PCI-related requirements.
• Contribute to CI/CD pipelines, deployments and release readiness, and support post-release monitoring.
• Monitor application performance and reliability, and improve performance, scalability, and cost efficiency in Azure.
• Identify technical debt and recurring problem areas and recommend and implement improvements.
• Independently own a workstream or product area (for example, terminal integration, merchant portal, or payment APIs), from design through deployment and ongoing support.
• Participate in daily engineering meetings to update teammates and management on status.
• Present technical expertise in training, implementation, and cross-team environments as needed.
• Perform other duties as assigned.

Education and Experience

• [3-6] years of professional software development experience, including: • Building and maintaining web applications and REST APIs
• Working within Agile or Scrum teams, including code reviews and version control workflows
• Writing automated unit and integration tests

• Proficiency in C# and .NET (.NET 8 preferred), including ASP.NET Core web APIs
• Experience with a modern JavaScript front-end framework, preferably Vue.js, along with HTML, CSS, and TypeScript or JavaScript
• Experience with cloud-based or NoSQL data storage, such as Azure Table Storage, Blob Storage, or similar
• Experience with Git-based source control and CI/CD pipelines (e.g., Azure DevOps or GitHub Actions)
• Preferred: experience in payments, fintech, or financial services
• Preferred: experience with the Microsoft Azure ecosystem, including Azure Functions, Service Bus or Queue Storage, Key Vault, Application Insights, and Log Analytics
• Preferred: knowledge of PCI DSS and secure software development practices

Knowledge, Skills and Abilities

• Strong understanding of software design principles, including API design, asynchronous processing, error handling, and distributed systems concepts.
• Working knowledge of payment flows and concepts, including authorization, settlement, chargebacks, refunds, reconciliation, tokenization, and encryption, or the ability to learn them quickly.
• Understanding of the trade-offs of working with non-relational storage, such as eventual consistency, limited transaction support, and query design driven by partition and row keys.
• Strong debugging and troubleshooting skills across web, API, data, and device layers.
• Highly organized and detail-oriented, with particular care where money movement or customer data is involved.
• Ability to prioritize and manage multiple tasks with composure, including time-sensitive production issues affecting merchants.
• Ability to maintain a positive and professional attitude in a fast-paced environment.
• Ability to work independently and as a contributing member of a team.

Physical Demands

• Must be able to remain in a stationary position for most of the day.
• Constantly operates a computer and other office productivity machinery.
• Occasionally handles and sets up payment terminals and related hardware.

Neumo Summary:

With the backing of four decades of public sector expertise and corporate capability, Neumo has successfully supported government services. Neumo was honored and recognized for four (4) consecutive years as a GovTech 100 Company representing the top 100 companies focused on making a difference in and selling to state and local government agencies across the United States.

Neumo is committed to helping communities thrive and brings a wealth of experience combined with innovation. Today, Neumo offers more administrative and financial support to government officials than any other organization. And with a responsive, client-focused approach, we foster partnerships that give our customers the certainty they need to accomplish more.

Neumo offers a competitive benefits and compensation package and are looking for team members who will thrive in our dynamic environment.

Neumo is an Equal Opportunity Employer. Selection for a position will be made without regard to race, religion, national origin, sex, political affiliation, marital status, non-disqualifying physical handicap, and age.