Tillster

Senior Software Engineer – Back End

Tillster
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2 months ago

Base Salary

$150k - $165k/yr

Responsibilities

  • Own the kiosk payment domain, including authorization, capture, voids, refunds, reversals, settlement, and reconciliation.
  • Re-architect the payment platform into a modular, pluggable SDK with plugin discovery, registration, versioning, backward compatibility, capability negotiation, dependency isolation, configuration, and secrets management.
  • Design a terminal abstraction covering integrated, semi-integrated, cloud, REST, and cash-payment processors and devices.
  • Build integration testing, simulation, certification, and regression-testing harnesses for new and external integrations.
  • Establish platform-wide patterns for idempotency, transaction recovery, reversals, timeouts, health monitoring, concurrency, and reconciliation.
  • Design PCI-DSS scope minimization using tokenization, P2PE, TLS/mTLS, and certificate and key handling, while partnering with security and QSA teams on audits.
  • Implement terminal integrations from byte-level protocols through the high-level PayTerminal API.
  • Work with serial and USB transports, including port handling, event-driven reads, reconnection, and timing.
  • Integrate processor APIs and terminal SDKs using REST, SOAP, webhooks, retry, polling, and reconciliation mechanisms.
  • Debug live hardware through protocol traces, terminal logs, packet captures, and vendor certification cycles.
  • Drive architecture and design reviews, set technical direction, and mentor engineers building integrations.

Requirements

  • 6+ years of backend engineering experience with strong Java, Spring, Maven, object-oriented programming, and distributed-systems design skills.
  • Demonstrated experience designing extensible plugin or SPI-based architectures, such as ServiceLoader, OSGi, Spring plugin models, or public SDKs used by other teams or third parties.
  • Hands-on experience with low-level device and protocol communication, including serial or USB communication and binary protocols such as TLV, BCD, bitmaps, length-prefixed fields, and state machines.
  • Direct payment-terminal or POS integration experience with providers such as Verifone, Ingenico, Adyen, Shift4, FreedomPay, SIX, Nepting, SiTef, Redsys, or Worldpay, or comparable platforms.
  • Strong understanding of card transaction lifecycles, PCI-DSS boundaries, tokenization, and TLS/mTLS in production.
  • Track record of technical leadership, including leading designs, setting standards, and mentoring engineers.
  • EMV, ISO 8583, ZVT, or OPI experience is a strong plus.
  • Experience with cash automation and recyclers, end-of-day and reconciliation tooling, regional acquiring, multi-currency payments, loyalty, stored value, gift, wallet integrations, Apple Pay, or Google Pay is desirable.
  • Vendor certification experience with acquirers and processors, 3-D Secure, SCA, or fraud and risk tooling is desirable.
  • Must be based in San Diego, California, for the hybrid role.

Benefits

  • Medical, dental, vision, FSA, healthcare and dependent-care reimbursement programs, an Employee Assistance Program, and Optum Care 24-hour confidential medical counseling services are available to eligible full-time employees and dependents.
  • Ten paid holidays are provided per calendar year.
  • Eligible full-time employees receive 15 days of PTO during the first 12 months and 22 days in subsequent years; eligible part-time employees receive prorated PTO.
  • Employees are eligible to participate in the 401(k) plan starting on their employment date.
  • College tuition and education assistance, Udemy courses, and ongoing learning and development opportunities are offered.
  • The role is hybrid and requires the candidate to be based in San Diego, California.
  • The position is a full-time regular employee role.

Tech Stack

JavaMavenSOAP

Categories

Tillster

About Tillster

201-500 employees
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