Tillster

Senior Software Engineer – Back End

San Diego Office · Senior · Part-time

No sponsorship$150k-$185kDetected 19 days ago

JavaSpringObject-Oriented ProgrammingRESTComplianceNegotiationRecruitingLeadershipCommunicationCritical ThinkingMentoring

About the role

Set platform-wide patterns for correctness in money movement: idempotency, transaction recovery and reversal, timeouts, heartbeat/health, concurrency, and reconciliation, in a system where double-charges and dropped captures are unacceptable.
Work directly with serial (RS-232 / USB-serial via jssc) and USB (usb4java) transports: port handling, event-driven reads, reconnection, and timing.
Integrate high-level and cloud processor APIs (REST/SOAP, webhooks, semi-integrated terminal SDKs) with robust retry, polling, and reconciliation.

Drive architecture and design reviews, set technical direction for the integration layer, and mentor engineers building integrations.
Implement new terminal integrations end to end, from byte-level protocol (framing, TLV/BMP/APDU, BCD/LLVAR, checksums, ACK/NAK state machines) up to the high-level PayTerminal API.
Embrace creativity and pursue new ideas to drive progress and improvement.
Own the payments domain end to end on the kiosk platform: authorize, capture, void, refund, reversal, settlement (EOD), and reconciliation.
Build the integration test and certification harness (extending the current mock-terminal approach) so a new or external integration can be validated, simulated, and regression-tested before it touches real hardware.
Design for PCI-DSS scope minimization: tokenization, P2PE, per-processor TLS/mTLS and certificate/key handling, so cardholder data stays out of in-scope services. Partner with security/QSA on audits.
6+ years back-end engineering with strong Java (the platform is multi-module Maven/Java on Spring) and solid OOP and distributed-systems design.

Solid grasp of the card transaction lifecycle (auth, capture, void, refund, settlement, reversal) and PCI-DSS boundaries, tokenization, and TLS/mTLS in production.
Hands-on low-level device and protocol experience: serial and/or USB communication and binary protocol implementation (TLV, BCD, bitmaps, length-prefixed fields, state machines).
EMV, ISO 8583, ZVT, or OPI a strong plus.

a layer of 40+ integrations spanning card-present terminals, semi-integrated and cloud processors, and cash automation.
(architecture and ownership)
Use strong critical thinking skills to make informed decisions based on accurate and relevant data.

All full-time, regular employees and their dependents are eligible for medical, dental, vision and FSA benefits.
Additional health benefits include Healthcare and Dependent Care reimbursement programs, Employee Assistance Program ("EAP") and Optum Care 24-hour confidential medical counseling services.
Paid Time Off (PTO): Full-time, regular employees earn 15 days of PTO in the first 12-months of continuous service, and 22 days in subsequent years.
Eligible part-time employees earn pro-rated PTO.
Retirement: Effective with your employment start date, you will be eligible to participate in the 401(k) Plan.
Education, Learning & Development: We offer college tuition and education assistance programs; Udemy Learning courses; and ongoing learning and development opportunities.
idempotency, transaction recovery and reversal, timeouts, heartbeat/health, concurrency, and reconciliation, in a system where double-charges and dropped captures are unacceptable.

Empower restaurants and consumers to engage and transact anywhere, anytime, and from any device - one consumer at a time, one order at a time, billions of times over.
In doing so, together we are transforming e-commerce in restaurants and make the till grow for Tillster and our customers.
Prioritize the needs and satisfaction of our customers in all decisions and actions appropriate to Tillster's stage of development, resources, and stated goals.
The company observes ten (10) paid holidays per calendar year.

This listing is sourced directly from Tillster's careers page and normalized into a canonical job model.