Full Stack Engineer (Kotlin / GCP), Payments Connectivity

About The Role You will join a team that builds and runs payment connectivity services integrating a large-scale online payments platform with external payment service providers. You will own features end to end across backend services, serverless components, cloud infrastructure, and CI/CD, and contribute to the customer-facing payment flows. What You’ll Do - Design, build, and maintain backend services that integrate with payment service providers for payment initiation and status retrieval. - Develop and support webhook and callback handlers that process asynchronous payment events reliably and securely. - Implement secure data exchange, including payload encryption and decryption and managed secrets. - Define and maintain well-documented APIs that follow internal standards and are validated through automated checks. - Secure inbound and outbound traffic using API gateway, edge, and cloud security controls. - Manage cloud infrastructure as code and deploy services on a serverless, container-based platform. - Build and improve CI/CD pipelines covering testing, validation, release automation, and deployment. - Support production through monitoring, incident triage, root-cause analysis, and payment status reconciliation. - Contribute to platform and edge improvements and to technical documentation. - Collaborate with platform teams and external provider contacts. Required Skills - Strong backend experience in Kotlin (or Java with a readiness to work in Kotlin) and a modern framework such as Micronaut or Spring Boot. - Hands-on experience with Google Cloud Platform (serverless compute, messaging, load balancing, security, secret management). - Experience designing and consuming REST APIs and OpenAPI specifications, and working with API gateways. - Solid understanding of webhook and callback patterns, idempotency, retries, and failure handling. - Working knowledge of encryption and secure data exchange. - Infrastructure as Code with Terraform. - CI/CD with GitHub Actions or an equivalent tool. - Strong testing discipline (unit, integration, contract) and observability practices. Nice to Have - Experience in payments or fintech, including PSP integrations, reconciliation, and PCI-DSS awareness. - Knowledge of CDN and edge security (WAF, routing, security rules). - Frontend skills (TypeScript, React or similar) for payment, redirect, or status-handling flows and internal tooling. - Familiarity with regional payment methods and regulatory guidelines. - Experience with event-driven architectures and microservices. - Experience with monitoring tools such as Dynatrace, Splunk, Prometheus, or Grafana.