Zuora Billing Service Integration

The problem

Sage needed an order management layer that could orchestrate subscriptions, invoicing, and payments across Zuora while remaining resilient under high-concurrency enterprise workloads — and producing customer-facing CSV and PDF invoices that satisfied finance, tax, and audit requirements.

Approach

• 01Architected the service on Dropwizard (Java 21) with Docker distroless images, deployed across dev, preprod, and prod via Terraform IaC.
• 02Modeled invoice generation in two formats — CSV for multi-field billing reports, PDF for the formal invoice document — using Java with AWS for storage and delivery.
• 03Stored generated documents on AWS S3 with KMS encryption; used DynamoDB for credit-management caching to keep hot reads off the billing system.
• 04Built an async event-driven pipeline with Guava EventBus + AWS SNS/SQS to fan billing events out to downstream systems including SII tax document generation.
• 05Applied functional error handling with Vavr monads so each step in the pipeline composes cleanly and surfaces failure without ambiguity.

Outcome

• End-to-end subscription, invoicing, and payment workflows running through Zuora with audit-grade document generation.
• Async pipeline isolates failure domains, so a downstream tax-document outage no longer blocks billing.
• Encrypted document storage and cached credit management reduce read pressure on the source-of-truth billing system.

Stack

• Java 21
• Dropwizard
• Vavr
• Guava EventBus
• AWS S3 · DynamoDB
• AWS SNS · SQS · KMS
• Terraform
• Docker
• Zuora Billing