Senior Systems Engineer

Role Purpose The Senior Systems Engineer builds, operates and supports Vumatel's integrations and payment integrations — the systems that connect our business platforms to the underlying fibre network infrastructure and to our external payment providers. These systems run 24/7 and are business-critical: an integration failure stops customer activations, service changes and payment collection, with immediate operational and revenue consequences. The role is therefore equally weighted between engineering new capability and keeping existing integrations reliable, observable, scalable and recoverable under load. Description Role Purpose The Senior Systems Engineer builds, operates and supports Vumatel's integrations and payment integrations — the systems that connect our business platforms to the underlying fibre network infrastructure and to our external payment providers. These systems run 24/7 and are business-critical: an integration failure stops customer activations, service changes and payment collection, with immediate operational and revenue consequences. The role is therefore equally weighted between engineering new capability and keeping existing integrations reliable, observable, scalable and recoverable under load. Reporting line and team structure Reports to: Principal OSS Solutions Architect. Works alongside: Systems Engineers on the Payments and NMS teams, the QA and BSS teams, Active Network team, together with the Platform/DevOps and Site Reliability functions who own the shared AWS and Kubernetes environments. Key Responsibilities Building and maintaining network integrations Write, test and review C# services that translate business-system events (new order, upgrade, downgrade, suspension, cease) into provisioning instructions issued to network element management and OSS platforms, and that feed the resulting state back to the originating system. Implement and maintain the API and messaging contracts between Vumatel systems and ISP partner systems, including request validation, retry and back-off behaviour, idempotency handling and duplicate suppression so that a repeated instruction never double-provisions a customer. Diagnose provisioning failures reported by the NOC or Service Desk: trace the transaction through application logs and message queues, identify whether the fault sits with the request, the integration or the downstream network platform, and either correct the data, replay the transaction or raise the defect with the responsible party. Monitor the integration platforms for exceptions and failed transactions, investigate the underlying fault, and drive each to resolution — whether by correcting data, replaying the transaction, patching the integration or escalating to the responsible system owner — working the outstanding exception backlog down on a scheduled basis rather than allowing it to accumulate. Building and maintaining payments Develop and support the C# services that initiate payment instructions to payment service providers, receive and verify provider callbacks and webhooks, and record payment outcomes against customer accounts. Build and maintain reconciliation processes that compare Vumatel's records against provider settlement and statement files, and investigate variances with Finance until each is explained or corrected. Prepare the integrations for scheduled high-volume events, in particular month-end and debit order collection runs: confirm capacity headroom in advance, monitor throughput and rejection rates during the run, and remain available for issues arising from it. Implement and maintain secure handling of payment credentials and sensitive data, including secrets stored in AWS Secrets Manager, key rotation, encryption in transit and at rest, and restriction of sensitive values from application logs. Data and persistence Design, review and evolve PostgreSQL schemas supporting the integration platforms, including indexing #J-18808-Ljbffr