Senior Software Engineer – Back End

About the role

Tillster, headquartered in San Diego, CA, is the global leader in digital ordering and customer engagement solutions. Founded over a decade ago, Tillster develops innovative self-service, ordering, and payments solutions for various POS systems, including 15+ unique systems covering over 90% of multi-unit restaurants.

Responsibilities

• Own and evolve the payment-terminal platform behind our kiosks, re-architecting it into a modular, pluggable SDK.
• Design the plugin contract and lifecycle, ensuring backward compatibility and secure handling of secrets.
• Build an integration test and certification harness to validate new integrations before they touch real hardware.
• Implement new terminal integrations, working directly with serial and USB transports, and debug live hardware.
• Drive architecture and design reviews, set technical direction for the integration layer, and mentor engineers building integrations.

Requirements

• 6+ years of back-end engineering with strong Java expertise and solid OOP and distributed-systems design.
• Demonstrated experience in designing extensible and plugin-based architectures.
• Hands-on low-level device and protocol experience, including serial and USB communication.
• Direct payment-terminal integration experience with Verifone, Ingenico, Adyen, Shift4, FreedomPay, SIX, Nepting, SiTef, Redsys, Worldpay, or similar systems.
• A clear understanding of the card transaction lifecycle, PCI-DSS boundaries, and TLS/mTLS in production.
• Track record of technical leadership, leading designs, setting standards, and mentoring engineers.

Qualifications

• Strong grasp of the card transaction lifecycle and PCI-DSS boundaries.
• Experience with cash automation and recyclers, end-of-day and reconciliation tooling.
• Regional acquiring experience and multi-currency payments.
• Vendor certification experience with acquirers and processors, including 3-D Secure / SCA and fraud/risk tooling.

Skills

• Extensive experience with Java and Spring framework.
• Strong knowledge of OOP principles and distributed systems.
• Hands-on experience with low-level device and protocol implementation.
• Experience with payment terminal integrations and PCI-DSS compliance.

Benefits

• $150,000 - $185,000 salary DOE
• All full-time, regular employees and their dependents are eligible for medical, dental, vision, and FSA benefits.
• Healthcare and Dependent Care reimbursement programs, Employee Assistance Program, and Optum Care services.
• 10 paid holidays per calendar year.
• 15 days of PTO in the first 12 months of continuous service, increasing to 22 days thereafter.
• Eligible part-time employees earn pro-rated PTO.
• 401(k) Plan eligibility.
• College tuition and education assistance programs, Udemy Learning courses, and ongoing learning and development opportunities.

Pay

• $150,000 - $185,000 DOE

Schedule

• Full-time position