Junior .NET Engineer in Madrid (required Ukrainian/Polish language)

POSITION OVERVIEW

We are looking for a Junior .NET Engineer to join a payment technology project in Madrid.

You will work at the intersection of engineering and partner success, supporting third-party partners throughout the full API integration lifecycle — from initial onboarding and configuration to testing, troubleshooting, and production launch.

This role is ideal for a junior engineer who enjoys solving real integration challenges, communicating with external partners, and gaining hands-on experience with payment systems. You will investigate API requests, JSON payloads, webhooks, and integration issues while working closely with Product and Engineering teams.

General project description

Licensed remittance and payment services provider focused on enabling fast, secure, and compliant money transfers. They operate within the fintech domain, serving international remittance corridors and integrating with multiple partners and financial institutions.

The role is on-site in Madrid (remote trial period is possible).

YOUR BACKGROUND

• 3+ years of experience in Information Technology
• Basic commercial or practical development experience with .NET and C#
• Hands-on experience working with REST APIs and JSON
• Ability to read code and understand request-and-response flows
• English level — B2+
• Additional languages — Ukrainian/Polish/French

Skills that will be a plus:

• Experience in fintech, payments, or banking infrastructure
• Familiarity with webhooks, API authentication (OAuth, API keys), and Postman or similar tools

RESPONSIBILITIES

• Onboard new third-party partners onto API platform, from first call to go-live
• Support partner integrations end to end: configuration, testing, and troubleshooting
• Act as the technical point of contact for partners, diagnosing issues across API requests, JSON payloads, and webhooks
• Reproduce, investigate, and resolve integration bugs — escalating to engineering when needed
• Write and maintain clear integration documentation, examples, and troubleshooting guides
• Feed recurring partner pain points back to product and engineering to improve the platform

WE OFFER

• A competitive, market-aligned salary
• Professional growth opportunities within a fast-growing international company
• A collaborative and dynamic environment with direct impact in the fight against financial crime
• Access to innovative technologies and regulatory practices
• A clear path for career progression with increasing responsibilities