Senior Fullstack Engineer (C#/.NET + Nodejs/Typescript - Payment Reconciliation) - DC29

YOUR NEW ROLE This role is for CODE LEAP's client company - JTL-Software JTL-Software is one of Germany's leading providers of e-commerce and ERP solutions. More than 50,000 retailers rely on JTL every day to run their business. Our global development center in Vietnam is looking for talented people to build the next generation of these products. You'll work in an international team that pairs German software quality and Vietnamese speed to innovate.

Payment Reconciliation is the process of matching every incoming and outgoing payment against what our systems expect - invoices, refunds, chargebacks, and the settlement files we receive from banks and payment providers. Manually, it doesn't scale. Automated, it runs quietly in the background, flags only the cases that need a human decision, and gives Finance an auditable view of every euro. That's what this team will build, from scratch.

Next to payment reconciliation, you will also work on our Documents project, which produces and manages the business documents that our customers' ERP processes depend on. Its back-end is built in Node.js and TypeScript with Effect, so this role is not limited to .NET: you will design and build Documents services with Effect (typed errors, services and layers, resource-safe and concurrent code) and connect them to our .NET services and the React front-end. This is why hands-on Node.js and Effect experience is a must for this position.

As a Senior Software Engineer (full stack), you will

• Build the services behind our reconciliation engine: ingesting and normalising provider files, matching at scale, handling exceptions
• Build the interface where Finance reviews, investigates and resolves what the engine could not match
• Own correctness end to end: idempotent processing, traceable matches, safe reprocessing of historical data
• Integrate new banks and payment providers and keep those integrations maintainable
• Translate accounting rules into testable software, together with Product and Finance
• Shape the architecture of a greenfield system, across back-end and front-end, and set the engineering standard for it

Team The team is newly established. You will work with fellow engineers and an Engineering Manager in our Ho Chi Minh City office, collaborating closely with engineering teams in Germany and Vietnam and with the Product Managers in Germany. As one of the first engineers, you'll influence both the technical foundations and how the team works across two locations.

YOUR EXCITING TASKS

• You design and build the services behind our reconciliation engine – ingesting and normalising settlement files from banks and payment providers and matching them against our transaction data
• You own correctness: idempotent processing, traceable matches, and safe reprocessing of historical data
• You integrate new banks and payment providers and keep those integrations maintainable
• You build and maintain back-end services in Node.js and TypeScript with Effect, modelling failures as typed errors and composing services through layers, so that integrations and jobs stay testable and safe to retry
• You build the interface Finance works in all day – reviewing unmatched transactions, investigating discrepancies and resolving them – and make a data-heavy domain usable: large tables, search and filtering at high volume, drill-downs from summary to single transaction
• You build the review and resolution workflows – assigning cases, manual matches, comments and audit trails – and make uploads, imports and long-running jobs predictable, with clear progress and error reporting
• You own features end to end, from API contract to screen, and shape requirements with Product and Finance into software they can work with
• You make the architectural decisions for a greenfield system – backend modules and data model, frontend structure, state management and data fetching – and keep it observable, performant, accessible and well tested
• You review code and help set the engineering standard for a new team

YOUR PROFILE AND YOUR PERSONALITY

• Several years of professional experience building production software across the full stack. You may be stronger on one side, but you are productive on both.
• Backend development with C# and .NET: modular monoliths, bounded contexts, CQRS and the REPR / vertical-slice style, modern API frameworks (e.g. FastEndpoints, Minimal APIs) and document databases (e.g. Azure Cosmos DB)
• Professional Node.js and TypeScript experience on the server side, with hands-on production use of Effect (Effect-TS): typed errors, services and layers, resource-safe and concurrent code, retries and schedules. Strong React and TypeScript with modern build tools (Vite, turborepo)
• Design systems and component-based development (Storybook, TailwindCSS)
• State and data fetching with Jotai, TanStack Query and TanStack Router
• Performance optimization and accessibility in data-heavy web applications
• Solid testing practice: unit and integration tests in .NET, Jest and Playwright on the front-end
• Git and collaborative workflows: pull requests and code reviews
• Clear written and spoken English for working with colleagues in Germany

Nice To Have

• Experience with CI/CD pipelines (GitHub Actions) and basic knowledge of Kubernetes and Helm
• Experience with Banking/Financial solution

Benefits Await You At Code Leap

• Competitive salary and benefits
• Year-end bonus (13th-month salary)
• Generous annual leave of up to 18 days
• Additional premium health insurance
• Enjoy an endless selection of delicious refreshments, including gourmet coffee, beverages, snacks, and fresh fruits, all complimentary
• 1-on-1 coaching with experienced professionals
• Flexible work policy, which provides flexible hours to accommodate personal schedules and commitments
• Dynamic, fun, and agile environment, perfect for sharing and creativity
• Open-minded, kind & humble colleagues

CONTACT Come to talk to us at [email protected]

About Us With our expert teams spread across two continents, CODE LEAP provides innovative software solutions for venture-backed companies and leading enterprise businesses in Germany. Our teams in Berlin (Germany) and Ho Chi Minh City (Vietnam) work hand in hand to develop state-of-the-art solutions of the highest quality.

Because collaborating with the right people is the secret to our successful growth.

We future-proof organizations - be part of it!