Daniel Cárdenas

AI Automation Engineer: RAG · Edge ML · Firmware

I build practical AI systems: RAG pipelines, voice and document automation, Python APIs, and the embedded telemetry that makes edge ML useful in the real world.

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Mar 2026•Backend Automation Developer•2 min read

WhatsApp Ledger and Statement Bot

Local-first finance ledger foundation with FastAPI, Postgres, Excel import previews, PDF statements, registration, and WhatsApp webhook delivery.

FastAPIWhatsAppPDF Reports
PythonFastAPIPostgreSQLWhatsAppPDFAutomation

Outcomes

  • FastAPI service with Postgres and Alembic migrations
  • Excel import preview and member statement PDF generation
  • WhatsApp webhook flow for registration and statement delivery

Problem

Finance and membership workflows often depend on Excel files, manual statement generation, and repeated WhatsApp messages. This project turns that into a backend foundation that can import data, generate statements, and answer member requests through a simple WhatsApp flow.

Approach

  • Built a FastAPI backend backed by PostgreSQL and Alembic migrations.
  • Added admin import preview endpoints for monthly Excel workbooks.
  • Generated member statement PDFs by document ID and month.
  • Implemented a public registration page so members can link their document ID and WhatsApp number.
  • Added WhatsApp webhook verification and inbound message handling through Meta configuration.
  • Supported a simple menu flow where registered users can request the latest available monthly statement.

Results

  • A repeatable local-first service that can be started with Docker Compose and Make targets.
  • Document IDs are normalized before lookup, reducing errors from punctuation or formatting differences.
  • The WhatsApp flow gives users self-service access to statements without exposing admin tools.