Java Developer (Payment Gateway /Gateway)

Java Developer
Employment Type: Full-time, Remote
Experience: 6+ years
Industry: Fintech / Payment Systems
About the Role
We are looking for a Java Developer (Payment Gateway / Gateway) to join RDC Partner. In this role, you will work with the engineering team of our US-based business partner in the fintech industry.
Our business partner develops solutions covering card payment processing, payment gateways, virtual POS, physical POS terminals, and payment infrastructure for merchants.
In this role, you will contribute to the development, maintenance, and enhancement of payment gateway solutions, working on payment transaction flows, bank and processor integrations, and payment system reliability. You will collaborate with teams based in the US and Türkiye to build and maintain secure, scalable, and reliable payment infrastructure. This is a fully remote position requiring strong Java development skills, the ability to work independently, and flexibility to collaborate with US-based teams during overlapping business hours.
What we are looking for
6+ years building production backend services in Java, including recent hands-on Spring Boot work.
Payments experience: you have worked on a gateway, switch, acquiring platform, POS integration or a direct processor or bank connection, and you understand what the money is doing as well as what the code is doing. Experience with Turkish payment infrastructure — BKM, bank VPOS integrations, or a domestic switch or gateway — is directly relevant. Our partner will provide training on Fiserv specifics
Direct experience with host message protocols — ISO 8583, or an XML equivalent such as Fiserv GMF — including STAN and RRN handling, reversals, timeouts, and idempotency when a response is lost rather than refused.
Comfortable below the framework: raw sockets and HTTP transport, connection management, TLS and certificate handling, and debugging a connection that fails intermittently.
A working understanding of card data security — tokenization, 3DES and DUKPT, PIN block handling — and what PCI DSS requires of the code path, including what must never reach a log.
Relational data modeling with JPA and Spring Data, and enough SQL to diagnose a production problem rather than guess at it.
Demonstrated ability to improve an inherited codebase with known defects while keeping it running — including at least one framework or major dependency upgrade you have carried out yourself.
Daily hands-on use of AI coding tools (Claude Code, Cursor, GitHub Copilot or similar) with a clear view of where they help and where they mislead. In a payments codebase, reviewing generated code carefully is not optional.
Able to reason about architecture — service boundaries, failure modes, what happens when the processor is unreachable — and to explain a trade-off rather than recite a pattern.
Genuinely hands-on. You will be writing code every day on a team small enough that there is nobody to delegate to.
Strong written and spoken English. You will be writing design notes read by the US team and joining live calls with them, and at times with our processor.
Proven ability to work independently in a remote team with asynchronous communication.
Availability for at least four hours of overlap with US Eastern Time business hours. In practice this means working into the early evening Türkiye time.
Nice to have
Fiserv or First Data platform experience — Omaha, North, RapidConnect, Datawire or GMF.
EMV, contactless and semi-integrated POS work, and terminal families such as IDTech, PAX, Dejavoo or Valor.
TransArmor or another tokenization or vault service.
HSM integration, key management and key ceremonies.
Having been through a processor or device certification as a developer, not only as an observer.
Spring Boot 3.x migration experience from a 2.x codebase.
Observability tooling, message queues, and performance work on transaction-processing systems.
Prior experience working remotely for a US or European company.

Work arrangement
Yes