C#/.NET | Payments & Core Financial Systems

Position Overview

CruwX is seeking a hands-on Senior Backend Engineer to participate in the development, integration, and support of mission-critical financial and payment platforms.

This is a highly technical, code-writing role focused on building backend financial systems and payment integrations. We are looking for a senior C#/.NET engineer with authentic payment industry experience—someone who understands transaction lifecycles, core financial messaging, and payment security standards, not an infrastructure-only architect.

Core Requirements

- Experience: 8+ years of software development experience, with 5+ years in fintech, banking, payment processing, or remittances.
- Technical Stack: Advanced hands-on experience with C# / .NET Core (.NET 8) and enterprise-grade distributed architectures.
- APIs & Enterprise Integrations: Deep expertise building, securing, and consuming robust REST & SOAP APIs . Proficient in financial integration standards and authentication protocols ( OAuth 2.0, JWT, Mutual TLS, HMAC Authentication ) to connect with banks, processors, and core networks.
- Core Payments Knowledge: Deep understanding of real-time transaction lifecycles (authorizations, routing, reversals, settlement,



clearing, and reconciliation).
- Financial Messaging Standards: Hands-on experience or familiarity with ISO 8583 (over TCP/IP sockets) and/or ISO 20022 (PACS, CAMT, PAIN).
- Integrations & Gateways: Proven track record integrating, certifying, or supporting Payment Processors, Card Networks, Merchant Acquirers, or Core Banking Systems.
- Payment Security & Compliance: Practical understanding of PCI DSS standards, secure coding practices, and payment encryption ( HSMs , cryptographic key management, PIN encryption, or EMV).
- Production Operations: Comfortable troubleshooting critical production issues, analyzing system logs, and supporting stable deployments.
- Languages: Professional fluency in both English and Spanish .

Highly Desirable

- Database Management: Strong proficiency in Microsoft SQL Server development, query optimization, or advanced administration (AlwaysOn, replication).
- Cloud Infrastructure: Experience deploying and managing workloads on AWS.
- Digital Assets & Tokenization: Experience in digital asset integration (wallets, stablecoins, custody, or external exchange rails like Coinbase).

📌 Senior Backend Engineer – Payments & Fintech (Argentina)
🏢 CruwX
📍 Argentina