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 Spa

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