Non-Functional Test Engineer (NFT Engineer) - POS Terminal

Role overview

Expleo is hiring two Non-Functional Test Engineers for a POS-focused initiative: one senior-level and one mid-level. The work centers on validating how well cloud-native services, device-based components, and payment ecosystem elements perform under real-world and high-volume conditions.

The role spans the complete payments landscape, including the Payment App, TMS 3.0, POS TMC, Nexo Retailer/Acquirer protocols, downstream integrations, and Android POS device performance. The objective is to confirm that enterprise-grade non-functional requirements are consistently met for load, latency, resilience, device behaviour, and operational stability.

Performance and load testing

• Review, define, and sharpen non-functional requirements for the solution.
• Create and run load, stress, spike, endurance, and soak tests across SmartPOS payment application services.
• Test TMS 3.0 processes such as downloads, commands, and updates.
• Validate POS TMC synchronization and update flows.
• Assess Nexo Retailer/Acquirer interactions.
• Test downstream integrations including IPG, BAM, EventGateway, and telemetry-related components.
• Track key performance measures such as transaction throughput, end-to-end latency from POS to IPG to EventGateway to BAM, resource usage, and SLA compliance.

Device performance testing

• Check Android POS hardware behaviour for CPU, memory, battery, and thermal impact.
• Measure application responsiveness, cold and warm start times, network handover performance, and long-session stability.
• Carry out 24-, 48-, and 72-hour soak tests on device builds.

Cloud-native resilience testing

• Test microservices running in Kubernetes and other containerized environments.
• Validate auto-scaling and load-balancing behaviour.
• Assess resilience when pods restart.
• Evaluate canary and blue-green deployment performance.
• Review queue performance across Kafka, SQS, and Pub/Sub.
• Run distributed failover and recovery scenarios.

Security and compliance checks

• Verify TLS handshake performance, secure API headers, rate limiting, and request integrity.
• Confirm PCI-aligned behaviour while systems are under load.
• Ensure logs do not expose sensitive data during stress testing.

Observability, logging, and reporting

• Investigate logs and dashboards across Kibana, Splunk, Prometheus, Grafana, CloudWatch, ELK, and tracing tools such as Jaeger and Zipkin.
• Spot abnormal patterns such as rising error rates, reduced throughput, growing latency, or unusual retry and throttling activity.
• Produce structured NFT deliverables, including the performance strategy, test scripts, execution output, KPI dashboards, and bottleneck/risk analysis.
• Contribute to Agile and SAFe ceremonies and support ongoing process improvement.

Qualifications

A third-level qualification in Computer Science, IT, or Software Engineering is required.

Essential technical skills

• Performance testing tools such as JMeter, Gatling, and Locust; LoadRunner is a plus.
• Android profiling utilities such as ADB, logcat, and CPU/battery profilers.
• Kubernetes administration and troubleshooting, including kubectl, Helm, deployments, and scaling.
• Docker-based container analysis.
• API gateway performance exposure with tools or platforms such as AWS API Gateway, Kong, Apigee, or NGINX.
• Monitoring and observability platforms like Prometheus, Grafana, CloudWatch, ELK, and Kibana.
• Understanding of VPC networking, load balancers, and Redis caching.
• Messaging systems such as Kafka, SQS, and Pub/Sub.
• REST API performance testing and JSON/XML payload handling.
• Working knowledge of Nexo Retailer/Acquirer flows.
• Performance analysis of TLS and OAuth/JWT overhead.
• Scripting in Python or Bash, with the ability to integrate scripts into CI/CD and automate log parsing and KPI extraction.
• Payments and POS domain knowledge, including EMV transaction lifecycles, host authorization, settlement, cryptography impacts, EMV tags, Android POS hardware limits, and TMS functions such as key loading, parameter updates, and firmware updates.

Desired qualities

• Strong client-facing ability and clear communication skills.
• Comfort working collaboratively and handling pressure with emotional maturity.
• Good self-management and a mindset focused on sustained performance.
• Creative problem-solving balanced with caution and attention to detail.
• Open, transparent working style and confident presentation skills.

Experience profile

This opening covers two levels:

• Senior NFT Engineer: 5 to 8+ years in QA, including 3 to 5+ years focused on NFT/performance testing, plus 2 to 3+ years in cloud-native performance engineering. Experience leading performance testing for distributed microservices and working deeply with Kubernetes, observability stacks, and large-scale load testing is expected.
• Mid-Level NFT Engineer: 3 to 6 years in QA, with 1 to 2 years in NFT/performance testing. Candidates should have strong hands-on experience with JMeter or Locust, log analysis, and practical exposure to Kubernetes, microservices, and cloud fundamentals.

Benefits

Expleo offers a competitive salary and a strong benefits package that includes wellbeing support, financial benefits, and recognition programmes. The company also promotes an inclusive culture, family-friendly policies, enhanced leave options, and meaningful learning and development opportunities.

• Collaborative environment with close partnership across teams and clients.
• Opportunities to grow technical skills through engaging and challenging projects.
• Access to Expleo Academy and accredited training courses.
• Company benefits such as medical and dental insurance, pension, life assurance, wellbeing support, sports and social events, birthday hampers, and more.
• A culture that values bold thinking, teamwork, and constructive challenge.

Equal opportunity statement

Expleo is an equal opportunities employer and welcomes applications from qualified candidates regardless of race, sex, disability, religion or belief, sexual orientation, or age.

Additional information

The company also notes that candidates should not be discouraged by impostor syndrome and encourages applications from anyone who believes they meet the role’s values, requirements, and competencies.