Senior .NET Developer - Payments

We are looking for a DOT NET CORE developer with ASP.NET, nodel.js, WebAPI and Digital Payments – as core skills for one of our projects

The project is onsite Seattle – Onsite  – about 24 months 

The selection and onboarding will happen quickly for qualified candidate

Services & API                   ASP.Net/Core, HTML, CSS, Micro services, Web API, WCF,  Web Services, MVC,

Payments Processing    Payments programming and interfacing with various payments online banking products;

Web Development         HTML,DHTML, CSS, Java Script, JQuery, XML, XSLT, AJAX, Design patterns

Database:                             SQL Server (SSIS, SSRS), Oracle 10g, Mongo DB, Cassandra

Cloud Platform:                AWS - VPC, MS-AZURE Private Cloud

Reporting Tools:                Crystal reports 10, SQL Server Reporting Services, SSIS         

Data Modeling Tools:      Erwin 4.0, Microsoft Visio, Enterprise Architect

Experience needed in Digital and Payments/Virtual Channels, various full stack Digital banking and Consumer lending project initiatives (Line of business - Credit Cards, Home Equity (HEQ), Wealth management, Credit lines, Auto loans). Experience with Single sign on framework (SAML technology) for Mortgage Loan Services

Responsibilities

• Work with infrastructure that powers in-person, tap, dip, and swipe transactions at point-of-sale,
• Deep payments domain expertise with strong backend engineering and integration fundamentals
• Hands-on experience with EMV payment flows including chip, contactless/NFC, and magnetic stripe, ideally including direct involvement in EMV Level 3 certification processes.
• Design, develop, and maintain backend services that manage communication between payment terminals and our processing infrastructure, supporting EMV chip, NFC/contactless, and magnetic stripe transaction flows.
• Integrate with device management platforms and terminal SDKs including solutions such as Clover, Stripe Terminal, Square, and similar off-the-shelf card present providers, adapting their APIs to fit our platform architecture.
• Implement and maintain device hub capabilities including terminal provisioning, configuration management, firmware coordination, and health monitoring.
• Own and drive EMV Level 3 certification efforts in partnership with payment networks and device vendors, coordinating test plans, managing certification tooling, and resolving certification findings.
• Design and build card-present infrastructure with international markets in mind, accounting for regional EMV implementation differences, multi-currency support, and varying certification requirements across acquiring markets.
• Build scalable, maintainable backend services using .NET and C#, adhering to established architectural patterns and contributing to their evolution.
• Implement robust retry logic, timeout handling, and graceful degradation to ensure transaction integrity even in the presence of network instability or device failures.
• Write secure code that meets PCI DSS requirements across all card-present transaction flows, with a particular focus on cardholder data handling, encryption, and key management.
• Apply point-to-point encryption (P2PE) and tokenization standards correctly within device integration and transaction processing layers.
• Act as a technical resource and mentor for junior and mid-level engineers on the squad, supporting their growth through pair programming, code review feedback, and knowledge sharing.
• Document card-present domain knowledge including certification processes, integration quirks, device-specific behaviors

Qualifications

• Strong proficiency in C# and the .NET ecosystem, with experience building production-grade backend services and APIs.
• Experience integrating with payment terminal hardware and device management platforms, with an understanding of terminal communication protocols (TLV, ISO 8583, or similar).
• Solid understanding of PCI DSS requirements as they apply to card-present environments, including encryption, key injection, and secure cardholder data handling.
• Experience designing and building RESTful APIs with a focus on clarity, versioning, and reliability.
• Proven ability to build low-latency, high-reliability backend services in a payments or similarly demanding production environment.
• Direct experience with Clover, Stripe Terminal, Square, or similar off-the-shelf card present platforms and their developer SDKs.
• Familiarity with EMV kernel development/ customization, regional EMV certification requirements and acquiring bank differences across international markets.
• Background working with Ingenico, Verifone, PAX, or other terminal hardware vendors.
• Experience with network tokenization or scheme token management in a card-present context.