Software Engineer IV, Payment Platform

Toshiba Global Commerce Solutions - External•Durham, NC

About The Position

Toshiba Global Commerce Solutions is seeking a hands-on Senior Engineer IV to lead the transaction-processing core of our payment systems platform. Responsibilities include ownership of the terminal transport layer, store-and-forward (SAF) handling, decline and exception fallback logic, and BIN-based routing to ensure reliable card-present payments across our retail network. This is a hands-on role, not focused on requirements documentation or committee work. You will work directly with transport and transaction-state code, reproduce terminal-level failures, and manage fixes through to production. Success requires strong expertise in banking and card payments, including issuers, card networks, acquiring processors, authorization and settlement flows, and distributed-systems engineering. This position offers a clear path to payment architecture ownership. You will apply your distributed-systems and Java expertise, learn our payment transaction lifecycle and terminal protocols through hands-on defect resolution and root-cause analysis in your first year, and advance to architectural ownership of the payment transport and transaction-integrity layer. Our technology stack includes Java and JavaScript applications built with Maven and delivered through a Jenkins CI/CD pipeline. We use a Vue 3/TypeScript POS checkout client that interacts with our transaction and device APIs. Docker and Kubernetes support our build, test, and deployment processes. We use OpenTelemetry for observability across transaction and transport paths, and follow an AI-first development model in which coding agents operate within defined scopes and must provide test and security evidence before changes are accepted.

Requirements

Bachelor's degree in computer science or related field.
8+ years building production distributed systems in Java, with deep experience in stateful, protocol-level code such as sockets, retries, timeouts, backoff, and idempotency.
Direct experience with payment processing, card-present transaction flows, or another domain where correctness under partial failure (dropped connections, ambiguous responses, at-least-once delivery) has real financial consequences.
Strong debugging skills for intermittent, timing-sensitive defects, with the discipline to reproduce failures deterministically rather than relying on retries as a solution.
Working knowledge of PCI data security standards and what they require of code that touches transaction data.
Experience with high-availability configurations for backend services, including application server, database, and hardware failover.
Proficiency with Spring Boot, socket-level communication, Maven, CI/CD, and Git at team scale.
Clear technical writing, demonstrated through RCAs, ADRs, or design documentation that has been successfully adopted by others.
Comfort mentoring and reviewing other engineers' work in a shared, high-stakes codebase.
Sufficient Vue 3 and TypeScript proficiency to read and debug the POS Client codebase, and to negotiate API contracts with its engineers.
Daily, professional use of an AI coding agent in a production codebase, with the judgment to recognize when its output requires verification before acceptance.

Nice To Haves

Experience with EMV, contactless (Mastercard/Visa contactless specifications), or issuer/network certification processes.
Experience with store-and-forward or offline-transaction patterns in any domain, not only payments.
Familiarity with retail point-of-sale hardware or terminal integration.
Experience with cloud microservices (Azure) and container orchestration (Docker/Kubernetes).
Knowledge of SQL and non-relational databases such as MongoDB.
Knowledge of REST API design and Swagger/OpenAPI documentation.
Experience directing AI coding agents through bounded, spec-driven tasks in a regulated or high-consequence codebase, including writing repository-level agent instructions and triaging agent-generated review findings.
Software development related certifications.

Responsibilities

Take ownership of the TCP transport layer between terminals and the payment platform, including heartbeat and keepalive validation, idle-connection management, and reconnect or timeout handling.
Manage store-and-forward (SAF) behavior for declined or unreachable authorizations, ensuring fallback activates only for genuine connectivity or timeout issues, and not for legitimate declines that should not be queued or replayed.
Oversee BIN-based routing and processor or network selection logic, including handling BIN table changes, program updates, and network-specific contactless or EMV requirements.
Diagnose and resolve terminal-side exceptions and faults that appear as ambiguous errors, identifying root causes in code, protocol, or hardware and firmware interactions, rather than relying on retries.
Lead root-cause analysis for production payment-processing incidents that impact transaction integrity, collaborating with terminal firmware teams, network and processor integrations, and store operations to implement permanent solutions rather than temporary mitigations.
Define and enforce design standards for the transaction and transport layer through participation in Architectural Reviews, ensuring consistent retry, idempotency, and failure-classification practices across the platform.
Maintain PCI-compliant handling of transaction data throughout the transport and SAF paths, and ensure all changes in this layer meet compliance and certification requirements for payment processing.
Mentor engineers working in the transaction layer and review their changes to transport, SAF, and routing code, exercising sound judgment to prevent changes that compromise correctness for convenience.
Direct AI coding agents working in the transaction and transport codebase by defining their scope, providing necessary protocol and root-cause context, reviewing all accepted changes as you would a teammate’s pull request, and ensuring a mandatory human review for any changes affecting PCI-scoped or transaction-integrity code.