Principal Software Engineer

Applied Resource Group; Alpharetta (GA); On-site; USD 180,000 - 235,000; Full time

Job summary

Applied Resource Group is seeking a Principal Software Engineer – Payments & FinTech to design, build, and scale modern payment solutions handling millions of transactions across digital commerce, hospitality, restaurant, and retail.

This role focuses on secure, high-performance payment infrastructure powering merchant onboarding, transaction processing, digital wallets, subscriptions, POS integrations, and financial reporting.

Qualifications

• Minimum 7+ years of software engineering experience with payments.
• At least 3+ years delivering payment processing or FinTech solutions.
• Strong experience building RESTful APIs and distributed systems; cloud-native apps.
• Proficiency in SQL and database design; familiarity with PCI-DSS compliance.

Responsibilities

• Design and build scalable payment processing platforms and APIs.
• Integrate with Stripe, Adyen, Braintree, Square, and other gateways.
• Support card-present and card-not-present transactions and POS integrations.
• Lead merchant onboarding workflows and subscription billing solutions.
• Develop fraud detection, risk management, and regulatory compliance features.
• Collaborate with Product, Operations, and Finance teams on new products.
• Ensure system performance, reliability, and security at scale.
• Drive architecture reviews and mentor junior engineers.

Skills

7+ years exp

3+ years payments

RESTful APIs

Distributed systems

Cloud-native apps

SQL/DB design

CI/CD

DevOps

PCI-DSS knowledge

Tools

Stripe

Adyen

Braintree

Square

Authorize.net

Docker

Kubernetes

Job description

We are seeking a Principal Software Engineer – Payments & FinTech to design, build, and scale modern payment solutions supporting millions of transactions across digital commerce, hospitality, restaurant, and retail environments. This individual will play a critical role in developing secure, high-performance payment infrastructure that powers merchant onboarding, transaction processing, digital wallets, subscription billing, point-of-sale integrations, and financial reporting. The ideal candidate combines strong software engineering expertise with a deep understanding of payment ecosystems, financial technology, and regulatory compliance.

About the Role

We are seeking a Principal Software Engineer – Payments & FinTech to design, build, and scale modern payment solutions supporting millions of transactions across digital commerce, hospitality, restaurant, and retail environments. This individual will play a critical role in developing secure, high-performance payment infrastructure that powers merchant onboarding, transaction processing, digital wallets, subscription billing, point-of-sale integrations, and financial reporting. The ideal candidate combines strong software engineering expertise with a deep understanding of payment ecosystems, financial technology, and regulatory compliance.

Responsibilities

• Design and develop scalable payment processing platforms and APIs.
• Build integrations with payment gateways including Stripe, Adyen, Braintree, Square, and other processors.
• Develop solutions supporting card-present and card-not-present transactions.
• Create integrations with POS systems, restaurant management platforms, ecommerce platforms, and third-party financial systems.
• Design and implement merchant onboarding and account management workflows.
• Build recurring billing, subscription management, invoicing, and settlement solutions.
• Develop fraud detection, transaction monitoring, and risk management capabilities.
• Collaborate with Product, Operations, Finance, and Customer Success teams to deliver new payment products.
• Optimize system performance, reliability, scalability, and security.
• Ensure compliance with PCI-DSS, SOC 2, and financial regulatory requirements.
• Participate in architectural design reviews and technical leadership initiatives.
• Mentor junior engineers and contribute to engineering best practices.

Qualifications

• 7+ years of software engineering experience.
• 3+ years developing payment processing or financial technology solutions.
• Experience integrating with payment gateways such as Stripe, Adyen, Braintree, Square, or Authorize.net.
• Strong experience developing RESTful APIs and distributed systems.
• Experience building cloud-native applications in AWS, Azure, or Google Cloud.
• Proficiency with one or more backend technologies:
• C# / .NET
• Node.js
• Go
• Python
• Strong SQL and database design experience.
• Experience with containerization and orchestration technologies such as Docker and Kubernetes.
• Understanding of PCI-DSS compliance and payment security standards.
• Experience with CI/CD pipelines and modern DevOps practices.

Preferred Skills

• Experience supporting restaurant technology platforms.
• Experience with POS systems including Toast, NCR Aloha, Oracle Micros, Clover, or Square.
• Knowledge of ACH, RTP, Open Banking, and digital wallet technologies.
• Experience with embedded payments and payment facilitation models.
• Familiarity with KYC, AML, and merchant underwriting processes.
• Experience designing event-driven architectures and microservices.
• Exposure to high-volume transaction processing environments exceeding millions of transactions annually.

Pay range and compensation package

Deliver scalable payment solutions supporting business growth.

Equal Opportunity Statement

We are committed to diversity and inclusivity in our hiring practices.