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Senior Software Engineer (C#/PHP)/ 6 days ago

NMI
Attractive
Application ends: 2026-01-12

Quick Summary

This Senior Software Engineer role in Toronto focuses on designing, developing, and maintaining high-volume payment processing and core billing/invoicing systems, requiring advanced proficiency in C# and/or PHP. The position involves taking architectural ownership, mentoring junior developers, leading CI/CD improvements, optimizing databases, and ensuring stringent security and PCI DSS compliance for scalable, distributed applications. Candidates must have a minimum of 5 years of experience in complex software development, strong OOP knowledge, and expertise in database design and optimization.

Senior Software Engineer (C#/PHP) - Payment Processing Systems

NMI is seeking a passionate Senior Software Engineer to join our growing Development team, focusing on underlying systems investment. This role is crucial for driving the continued development of our high-volume payment processing services.

As a senior developer proficient in C# and/or PHP, you will join industry-leading experts responsible for software services that process billions of transactions annually for hundreds of thousands of merchants. These applications must be efficient, reliable, redundant, secure, highly-available, and scalable. Experience developing accounting or billing systems is preferred for this position.

Key Responsibilities

  • Design, develop, and maintain core billing and invoicing systems utilizing C# and PHP technologies.
  • Take ownership of architectural and design decisions for critical billing system components.
  • Lead technical discussions, conduct code reviews, and enforce best practices for maintainability and performance.
  • Actively mentor and support the professional growth of junior team members.
  • Lead improvements for CI/CD pipelines and overall development processes.
  • Implement robust monitoring, logging, and alerting systems to proactively identify and resolve system issues.
  • Optimize database queries and system architecture to effectively manage growing merchant and transaction volumes.
  • Implement stringent security measures to protect sensitive payment and merchant data, ensuring compliance with PCI DSS standards.
  • Communicate project status, risks, and technical decisions clearly to both technical and non-technical stakeholders.
  • Collaborate closely with Product Owners, Developers, and QA teams to ensure successful product releases.
  • Proactively identify, assess, and mitigate risks, including security risks, throughout the software development lifecycle (SDLC).
  • Provide resolutions and feedback for escalated support issues.
  • Research and evaluate new technologies and methodologies to enhance system performance and developer productivity.

Skills and Experience

  • Bachelor's degree in Computer Science or equivalent experience.
  • Minimum of 5 years of experience developing complex software applications within a collaborative, agile environment.
  • Advanced proficiency in C# and/or PHP, coupled with a strong understanding of object-oriented design principles and design patterns.
  • Advanced experience in database design, optimization, and performance tuning.
  • Strong knowledge of security and compliance best practices (e.g., OWASP, PCI).
  • Excellent communication skills, proven ability to mentor, contribute to a strong team culture, and facilitate cross-team project advancement.
  • Experience designing and architecting scalable, distributed systems, prioritizing performance, reliability, and maintainability.
  • Ability to translate complex business requirements into effective technical solutions.
  • Proven track record of conducting code reviews and maintaining high code quality standards.
  • Proven ability to understand, debug, and enhance complex existing systems despite limited documentation and evolving requirements.

Preferred Qualifications

  • Experience with logging systems (such as Logz.io) and optimizing logs.
  • Experience with containerization technologies (e.g., Kubernetes, Docker).
  • Experience with monitoring and alerting systems (e.g., DataDog, NewRelic).
  • Experience with CI/CD pipelines, automated testing, and deployment processes.

Benefits

  • Annual salary plus bonus.
  • A remote first culture.
  • Health, Dental, and Vision Insurance.
  • 13 Paid Holidays.
  • Company volunteer days.

About NMI

NMI enables partners with choice, challenging the one-size-fits-all approach to payments. We are the platform powering success for innovative technology created by SMBs, entrepreneurs, and fintech startups. We democratize the latest payments technology so that everyone can realize the benefits of easy payments across the full spectrum of commerce. We focus on enabling more payments in more ways and more places.

NMI is committed to providing equal employment opportunity for all persons regardless of race, color, religion, sex, age, marital status, national origin, sexual orientation or sexual identity, genetic information, citizen status (except those that do not have the legal right to be employed in the United States), disability, military service, service member, veteran status, or any other basis protected by applicable law.

Please note that in compliance with data protection regulations, personal information submitted with your job application may be collected and used by NMI for recruitment and employment-related activities. By submitting your application, you acknowledge and provide explicit consent to the processing of your personal information as described in our privacy policy found here: https://www.nmi.com/legal/privacy-policy/

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NMI

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