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Nexius AI: Building an AI Financial Document Processing SaaS
September 2025 - May 20266 min read

Nexius AI: Building an AI Financial Document Processing SaaS

A CV-backed look at the 7-stage Nexius AI platform: OCR, parsing, extraction, validation, journal mapping, reporting, and delivery.

AI SaaSFastAPIRabbitMQObservability

Product Scope

At Quantum Teknologi Nusantara (September 2025 – May 2026), I worked on Nexius AI, an AI-powered financial document processing SaaS. The platform converts uploaded financial documents into structured, validated outputs that users can review and download.

The product spans customer-facing upload flows, partner and affiliate portals, and internal admin dashboards, so engineering decisions need to support both product usability and operational visibility.

Backend Architecture

I standardized FastAPI service architecture using Domain-Driven Design so services remain maintainable as AI integrations and document workflows grow.

Long-running file-processing flows were moved from monolithic processing into RabbitMQ-based distributed workers and Kubernetes worker pods to improve scalability under high upload volume.

  • REST APIs for uploads, queue visibility, report/month processing state, and background jobs.
  • Server-Sent Events for real-time upload and processing progress.
  • Worker heartbeat, queue diagnostics, and progress snapshots for operational debugging.

AI Quality and Observability

The AI workflow includes transaction categorization, ambiguous transaction clustering, Chart of Accounts mapping, and metric-based validation.

I also improved observability with OpenTelemetry, SigNoz, structured logs, and queue diagnostics so production issues are easier to trace.