C# Developer

Our Client Overview

A fintech startup which focuses on revolutionising the way payments are processed with an emphasis on speed and user convenience. The company provides innovative solutions designed to streamline transactions and reduce wait times for both consumers and businesses. 

Purpose

We're looking to employ a C# / Classic ASP Developer, who will contribute to both the maintenance of the core payment infrastructure and the modernisation of the companies systems. This dual focus will provide you with the opportunity to balance supporting business-critical legacy applications with working on new, forward-thinking projects.

Their aim is to redesign their tech stack allowing for a more scalable, secure, and innovative platform. We’re looking for someone eager to be part of this transformation.

In this role, you will ensure the reliability of the payment systems while collaborating with the team and reporting directly to the CTO to identify and implement improvements and new technologies.

This is a unique opportunity to make an impact by driving change within a high-volume, high-transaction environment.

Tasks include:

• Maintain and enhance existing payment gateway features using C# and Classic ASP
• Troubleshoot and resolve technical issues within the payment processing platform, ensuring high availability and minimal downtime.
• Contribute to the modernisation of our tech stack, offering input on architectural decisions and process improvements.
• Collaborate with cross-functional teams to design and deliver innovative, scalable, and secure payment solutions.
• Build and maintain integrations with external payment providers, banks, and third-party APIs.
• Optimise the performance of legacy systems while helping migrate critical functionality to newer technologies.
• Ensure compliance with PCI DSS and other relevant security standards throughout the development lifecycle.
• Create and maintain technical documentation for both legacy systems and newly developed features.

Requirements: 

• 5+ years of experience in software development, with expertise in C# and Classic ASP
• Proven experience in maintaining and modernising legacy systems
• Strong understanding of payment gateways, transaction processing, and API integrations within a fintech environment
• Proficiency with SQL Server, including complex queries, stored procedures, and performance optimisation
• Solid understanding of web development fundamentals: HTML, CSS, JavaScript, and JSON
• Familiarity with RESTful APIs and experience integrating with external services (e.g., payment processors, banks
• Strong debugging and problem-solving skills, especially in high-transaction-volume environments
• Knowledge of security standards and protocols, including PCI DSS, encryption, and SSL/TLS
• Ability to work effectively in a dynamic environment and contribute to the redesign and improvement of systems

Desirable skills:

• Experience with cloud platforms like Azure or AWS
• Familiarity with modern payment standards such as 3D Secure, tokenisation, or open banking
• Exposure to microservices architecture or modernisation strategies
• Experience with CI/CD pipelines and automated testing in a fintech context
• Previous involvement in projects that migrated legacy systems to new architectures