Principal Software Engineer

About IXOPAY

IXOPAY is the enterprise-grade global payment infrastructure platform built for the era of agentic commerce. We equip merchants and enterprises with AI-driven intelligence, payment orchestration, advanced tokenization, and the tools to optimize every stage of the payments journey.

From intelligent routing and compliance to customizable modules and enterprise-scale orchestration, IXOPAY helps businesses integrate faster, improve payment performance, and expand globally with confidence.

At IXOPAY, our people are our greatest strength. Our collaborative culture is built on shared values that guide how we work, innovate, and support our customers.

What Makes an IXOPAYer?

We are a global team bound by one standard, where every voice matters and initiative drives real change. We thrive on progress over perfection - choosing direction over motion, working smart with modern tech and AI, and constantly learning through continuous iteration. If you are tenaciously curious, empowered to take ownership, and passionate about delivering customer-first solutions in the fast-paced world of global payments, you’ll fit right in.

About the Role

We're looking for a Principal Software Engineer to help define the technical direction of IXOPAY's next-generation payment orchestration platform.

Based within our Vienna engineering organization, you'll provide technical leadership across the architecture that powers intelligent payment routing, PSP and connector integrations, platform configuration, and the tokenization capabilities that support these payment flows.

This is a highly hands-on technical leadership role. You'll tackle some of the platform's most complex engineering challenges, make architectural decisions with impact across multiple teams, and help establish the engineering standards that enable IXOPAY to operate securely and reliably at enterprise scale.

Working closely with Product, AI, and Engineering leadership, you'll translate complex business challenges into technical strategy while mentoring engineers and influencing architecture across the organization.

This is an opportunity for an experienced engineer who wants impact beyond a single product or team—while remaining close to the technology and continuing to build production software.

What You'll Do

Define Platform Architecture

• Own and evolve the architecture and long-term technical direction of IXOPAY's payment orchestration capabilities, including intelligent routing, PSP and connector integrations, and platform configuration.

• Design scalable, resilient backend systems using C# and .NET that support high-volume, mission-critical payment processing.

• Shape how tokenization and token intelligence integrate into the broader orchestration architecture.

• Define secure and extensible APIs, services, and platform patterns that support customer-facing capabilities and emerging AI-powered workflows.

• Evaluate architectural approaches and build-versus-buy decisions, balancing scalability, security, performance, maintainability, and speed of delivery.

Solve Complex Engineering Challenges

• Identify systemic risks across performance, scalability, reliability, and security before they become customer-impacting issues.

• Lead the design and implementation of solutions to complex distributed systems challenges across the platform.

• Drive major architectural improvements and modernization initiatives from technical strategy through production implementation.

• Remain hands-on with production code, prototypes, architecture, and technical problem-solving.

Lead Technical Excellence

• Establish engineering standards, architectural principles, and technical best practices that improve quality and consistency across teams.

• Lead architecture and design reviews, challenging assumptions and helping teams make thoughtful technical trade-offs.

• Influence technical direction across multiple engineering teams without relying on direct reporting authority.

• Provide hands-on mentorship through code reviews, design reviews, architecture documentation, and technical guidance to engineers at multiple levels of seniority.

Collaborate Across the Organization

• Partner with Product, AI, and Engineering leadership to translate ambiguous business and customer needs into scalable technical solutions.

• Represent Engineering in cross-functional and leadership discussions around platform capabilities, scalability, architecture, and technical trade-offs.

• Collaborate with teams across the organization to ensure architectural decisions support both immediate product needs and IXOPAY's long-term platform strategy.

• Help create alignment around complex technical decisions and drive initiatives through implementation.

What You'll Bring

Required

• Extensive experience designing and building production backend systems, with demonstrated technical leadership at Principal, Staff, Lead Architect, or equivalent level.

• Deep expertise in C# and .NET, including experience architecting and operating highly scalable production systems.

• Strong experience designing distributed, high-throughput systems using RESTful APIs, event-driven architectures, or similar integration patterns.

• Strong understanding of relational databases, data modeling, distributed systems, and the architectural trade-offs required at scale.

• Experience designing secure, resilient cloud-based platforms and leading significant architecture or modernization initiatives.

• Proven ability to identify and address challenges related to scalability, performance, reliability, and security.

• Demonstrated technical leadership across multiple teams, including the ability to set direction, build consensus, and influence without direct authority.

• Experience mentoring senior engineers and raising engineering standards through architecture reviews, design reviews, and hands-on technical guidance.

• Excellent communication skills, with the ability to explain complex technical decisions and trade-offs to engineering, product, and leadership audiences.

• A hands-on engineering mindset and a desire to remain actively involved in the design and development of production systems.

Preferred

• Experience within payments, FinTech, financial infrastructure, or another high-volume transaction processing environment.

• Knowledge of payment orchestration, intelligent routing, PSP/acquirer integrations, or payment gateway architecture.

• Understanding of tokenization and its role within payment processing and orchestration.

• Experience designing plugin, connector, or adapter architectures for extensible platforms.

• Experience with Azure and services such as App Configuration and Key Vault.

• Experience architecting APIs or backend services that support AI- or LLM-powered applications.

• Understanding of PCI DSS, credential management, data protection, and payment security practices.

• Experience mentoring Principal, Staff, or other senior-level engineers.

Why Join IXOPAY?

At IXOPAY, you'll help define the architecture behind the next generation of enterprise payment infrastructure. You'll work on technically challenging problems at the intersection of distributed systems, AI, and global payments while collaborating with a small, highly experienced engineering team where your contributions have a direct impact.

We offer:

• Competitive salary and benefits

• Professional growth and development opportunities

• A collaborative, supportive engineering culture

Our Commitment to Inclusion

We know great candidates don't always meet every qualification. If you're excited about this opportunity, we encourage you to apply - we'd love to hear what you can bring to IXOPAY. What Makes an IXOPAYer? We are a global team bound by one standard, where every voice matters and initiative drives real change. We thrive on progress over perfection - choosing direction over motion, working smart with modern tech and AI, and constantly learning through continuous iteration. If you are tenaciously curious, empowered to take ownership, and passionate about delivering customer-first solutions in the fast-paced world of global payments, you’ll fit right in.

Equal Opportunity Employer

IXOPAY is proud to be an Equal Opportunity Employer. We consider all qualified applicants without regard to race, color, religion, sex (including pregnancy, sexual orientation, gender identity, or gender expression), national origin, age, disability, genetic information, veteran status, or any other characteristic protected by applicable law.

IXOPAY participates in E-Verify.