Payment Solution Engineer
At a glance
Mid-level Solutions & Sales Engineering role at Unlimit. Belgrade · full-time.
Pay not stated
Growth Roles summary, based on the employer's posting.
What you'll do
- Lead central-bank and clearing integrations from initial kickoff through production launch
- Serve as the technical and delivery contact for regulators and assigned counterparties
- Set up credentials, environments, certification tests, and production activation
- Build connections to local payment systems and integrate additional rails through BaaS providers
- Record each integration and transfer maintainable solutions to engineering and operations
What you bring
- At least five years in payments, banking, or integration engineering, owning complex integration work
- Hands-on experience connecting to central banks or national clearing and settlement systems
- Working knowledge of payment schemes, rails, clearing, settlement, and standards including ISO 20022 and MT/MX
- Ability to independently control regulated projects, including scope, timing, and regulator communication
- Practical use of LLMs, AI-assisted development environments, or automation frameworks
Who this fits
You’ll suit a mid-level solutions or sales engineering role that combines project leadership with hands-on technical implementation. The position requires clear communication with regulators and technical counterparts, plus familiarity with payment integrations and AI-supported engineering. It is an onsite, full-time role in Belgrade, Serbia.
From the employer
As Unlimit expands into new markets, each license we obtain connects us to that country's banking infrastructure — domestic clearing and direct interaction with other participants in the banking system. This role owns the integrations that bring those rails live: working hands-on with central banks, national clearing systems, and third-party BaaS providers.
You'll act as both project lead and solution engineer — running each integration with the regulator or provider and doing the technical implementation yourself. It's a role that sits between delivery and architecture: you own a project end to end while staying deep in the technical detail.
What You'll Be Doing
Own central bank and clearing integration projects end to end, from kickoff to go-live, as Unlimit enters new licensed markets.
Act as the primary technical and project contact for regulators and their assigned counterparts.
Manage the full onboarding path: credentials and environment setup, certification test cases, and production activation.
Set and defend realistic launch timelines, and keep projects on track within their delivery window.
Design and implement the connections that plug Unlimit into local clearing and payment systems.
Deliver integrations with third-party BaaS providers to bring additional payment rails online.
Document integrations and hand over clean, maintainable solutions to engineering and operations.
Our Tech Stack
You'll work across a stack that includes:
Backend & tooling: JVM, Kotlin, Java, Spring Boot, Modulith, Javalin, jOOQ, Temporal
Integration & messaging: REST and SOAP/XML web services, ISO 20022; Kafka and SQS/SNS for internal eventing
Security: mTLS, PKI, certificate-based authentication, and digital signatures — standard for central bank and clearing connections
Cloud & infrastructure: AWS, Docker, Kubernetes, Terraform, GitLab CI/CD
What We're Looking For
5+ years in payments, banking, or integration engineering, with hands-on ownership of complex integration projects.
Direct experience integrating with central banks and/or national clearing and settlement systems.
Hands-on familiarity with payment schemes and networks such as SWIFT and SEPA.
Strong understanding of payment rails, clearing, and settlement flows.
Comfort with payment messaging standards and integration patterns (ISO 20022, MT/MX, SOAP/REST web services, certificate-based auth).
The ability to run a regulated project independently — managing scope, timelines, and regulator communication without close supervision.
A solid awareness of AI-driven engineering practices and where the tooling is heading.
Hands-on experience putting AI tools to work — LLMs, AI-assisted development environments, and automation frameworks — to sharpen productivity, system performance, or technical decision-making.
A clear, structured communicator who can hold their own with regulators and technical counterparties alike.
Nice to Have
Experience working directly with financial regulators, especially in Europe, Mexico, and Brazil.
Familiarity with local schemes such as SEPA (Europe), SPEI (Mexico), and Pix (Brazil).
Prior BaaS / embedded-finance integration experience.
A background in payments, banking, or fintech operating across multiple jurisdictions.
What You'll Gain
Ownership of high-impact projects that directly unlock new markets for Unlimit.
Exposure to the full fintech product landscape: acquiring, BaaS, wallets, crypto, and more.
A global company with a strong engineering culture, agile mindset, and flat hierarchy.
Collaboration with international teams across EU, LATAM, and APAC.
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