AppCard is seeking a Senior Systems Engineer with strong expertise in Linux systems, infrastructure automation, and TCP/IP–based network troubleshooting, supporting production environments and customer-facing POS integrations. This is a hands-on operational role responsible for system reliability, automation, and advanced incident resolution across Linux infrastructure, POS networks, and data pipelines. The role works closely with Engineering, Product, Customer Success, and Support to ensure platform stability and an excellent customer experience. Responsibilities:- Administer, monitor, and troubleshoot Linux-based production and customer-facing systems supporting POS integrations- Design, implement, and maintain Ansible-based automation for configuration management, deployments, and system consistency- Diagnose and resolve TCP/IP protocol–level issues; troubleshoot POS environments; act as an escalation point for complex incidents; perform database troubleshooting; collaborate with Engineering; use monitoring and observability tools; document system architecture and runbooks; manage multiple concurrent issues; participate in off-hours/on-call rotations Requirements:- Bachelor’s degree in CS/IT (or equivalent experience); strong hands-on Linux administration; proven Ansible experience; solid understanding of TCP/IP; experience supporting or integrating with POS systems; working knowledge of databases and SQL; familiarity with monitoring/logging/alerting tools; 3+ years in Systems Engineering/Technical Operations/advanced Support; strong analytical and communication skills; highly organized. Nice to have:- Grafana for monitoring; Salesforce experience; exposure to IoT/edge devices/distributed retail; scripting (Bash, Python). * This position requires off hour support and weekends *This role is full-time from the office in NYC.Salary Range: $70,000 – $85,000.