Tillster

Senior Software Engineer - Back End

Tillster • $150K — $185K *
San Diego, CA 92154In-Person
Information Technology
5 - 7 years of experience
Today
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Job Overview by Ladders

Qualifications

  • 6+ years back-end engineering experience, primarily in Java (Maven/Spring)','Strong knowledge in OOP and distributed systems design','Proven track record in designing extensible, plugin architectures (ServiceLoader, OSGi, etc.)','Experience in low-level device/protocol communication (serial/USB, binary protocols)','Familiarity with payment-terminal integrations and card transaction lifecycle','Demonstrated leadership in technical designs and mentoring teams

Responsibilities

  • Own and manage the end-to-end payments domain for the kiosk platform
  • Re-architect the payment platform into a modular SDK for better integration
  • Design a terminal abstraction covering various integration models
  • Develop and enhance integration testing and certification tools
  • Establish correctness patterns for financial transactions
  • Ensure PCI-DSS compliance in platform design and operations
  • Lead architectural discussions and mentor engineering teams

Benefits

  • Comprehensive medical, dental, and vision coverage for employees and dependents
  • 403(b) retirement plan participation from day one
  • 15 days of paid time off in the first 12 months, increasing to 22 days in following years
  • Ten observed paid holidays per year
  • Tuition reimbursement and learning assistance programs available
  • Access to ongoing professional development opportunities through various courses
Full Job Description
Role: Senior Software Engineer - Back End
Hybrid Role, MUST BE BASED IN SAN DIEGO, CA

About the Role

We are looking for a Senior Engineer (bordering on Architect) to own and evolve the payment-terminal platform behind our kiosks: a layer of 40+ integrations spanning card-present terminals, semi-integrated and cloud processors, and cash automation. You will re-architect this into a modular, pluggable SDK so internal teams and external/third-party developers can build new integrations against a stable, versioned contract without forking the core, and you will stay hands-on, implementing new integrations down to the wire-level protocol.

What You'll Do (architecture and ownership)
  • Own the payments domain end to end on the kiosk platform: authorize, capture, void, refund, reversal, settlement (EOD), and reconciliation.
  • Re-architect the platform into a pluggable payment SDK: design the plugin contract and lifecycle (discovery/registration, versioning and backward compatibility, capability negotiation, dependency isolation, per-integration configuration and secrets) on top of the existing PayTerminal SPI.
  • Design a terminal abstraction that cleanly spans integrated vs. semi-integrated vs. cloud/REST processors and cash devices, so callers code to one model regardless of transport or vendor.
  • 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.
  • 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.
  • 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.
  • Drive architecture and design reviews, set technical direction for the integration layer, and mentor engineers building integrations.


What You'll Do (hands-on, low to high level)
  • 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.
  • 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.
  • Debug live hardware: protocol traces, terminal logs, packet captures, and vendor certification cycles.


About You (required)
  • 6+ years back-end engineering with strong Java (the platform is multi-module Maven/Java on Spring) and solid OOP and distributed-systems design.
  • Demonstrated experience designing extensible / plugin / SPI-based architectures (ServiceLoader, OSGi, Spring plugin models, or public SDKs consumed by other teams or third parties).
  • 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.
  • Direct payment-terminal / POS integration experience (Verifone, Ingenico, Adyen, Shift4, FreedomPay, SIX, Nepting, SiTef, Redsys, Worldpay, or comparable), and a clear understanding of integrated vs. semi-integrated models.
  • Solid grasp of the card transaction lifecycle (auth, capture, void, refund, settlement, reversal) and PCI-DSS boundaries, tokenization, and TLS/mTLS in production.
  • Track record of technical leadership: leading designs, setting standards, and mentoring engineers.


Nice-to-haves
  • Cash automation and recyclers (Vynamic Cash or similar), end-of-day and reconciliation tooling.
  • Regional acquiring experience (LatAm, EU, Middle East) and multi-currency payments.
  • Loyalty, stored-value, gift, or wallet (Apple Pay / Google Pay) integration.
  • Vendor certification experience with acquirers and processors; 3-D Secure / SCA, fraud/risk tooling.

The Interview Process
  1. Recruiter interview with a Talent Acquisition Specialist
  2. Interview with Hiring Manager
  3. Technical Assessment
  4. Interview with our Kiosk-Payment Team
  5. Final Interview-Head of Kiosk


Pay and Benefits (USA)
  • Salary is $150,000 - $185,000 DOE
  • Health Benefits: 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.
  • Holidays: The company observes ten (10) paid holidays per calendar year.
  • 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.

Local Candidates Only
No Visa Sponsorship
Principals only - no Agencies or calls please

About Tillster

Tillster is a software company that provides digital ordering and engagement solutions for the restaurant industry. The company's products include online ordering, mobile ordering, and loyalty programs. Tillster's software is used by some of the world's largest restaurant chains, including Burger King, KFC, and Pizza Hut. The company was founded in 2009 and is headquartered in Los Angeles, California. Tillster has additional offices in San Diego, California and London, United Kingdom.
Learn more about Tillster
Size
500 employees
Industry
Enterprise Technology
Founded
2002
* Ladders Estimates

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