Context
Course purchases were already being paid through Stripe, but the downstream accounting workflow needed a paid Stripe invoice, not only a captured payment.
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Case study / Financial Ecosystem
Accounting-ready invoices from completed Stripe payments.
A private client needed to close the gap between successful Stripe payments and the paid invoices required by downstream accounting workflows. MT Software built a secure webhook automation that creates paid invoices without charging customers twice.
System overview
Automation model
Stripe payment flow from webhook event to paid invoice
Input
Stripe payments
Completed LearnWorlds purchases arrive through Stripe Checkout or PaymentIntent webhook events.
Review
Webhook automation
Events are validated, persisted, checked for eligibility and protected against duplicate invoice creation.
Handoff
Paid invoice
The backend creates, finalizes and marks the Stripe invoice as paid for downstream accounting tools.
System-level workflow representation showing how successful payments become paid, audit-ready invoices.
Overview
From paid transactions to accounting-ready invoices.
The project focused on a backend automation layer that reconciles payment success with the invoice structure required by accounting and bookkeeping workflows.
Challenge
Stripe events can be retried, replayed or delivered through different event types, so the automation had to avoid duplicate invoices and preserve traceability.
Solution
MT Software built a Fastify backend that validates webhooks, resolves payment data, creates invoices, marks them paid out of band and stores processing links.
Outcome snapshot
A reliable bridge between payment success and accounting readiness.
The case focuses on structural outcomes: paid invoice creation, duplicate-safe processing and operational visibility across Stripe webhook events.
Invoice automation
Completed Stripe payments are transformed into finalized invoices marked as paid without charging buyers again.
Duplicate protection
Database constraints, Stripe idempotency keys and payment-invoice links reduce duplicate invoice risk.
Operational audit trail
Events, processing status, invoices and adjustments are persisted for diagnosis and controlled reprocessing.
Solution design
A backend pipeline designed for financial reliability.
The implementation focused on safe webhook handling, deterministic payment-to-invoice processing and operational tooling for recovery when external systems behave unpredictably.
Webhook processing
A Stripe webhook endpoint validates signatures, captures raw body input and persists events before processing.
Paid invoice creation
The service creates invoice items, finalizes invoices and marks them paid out of band.
Idempotency controls
PaymentIntent links, unique database constraints and Stripe idempotency keys prevent duplicate invoices.
Adjustment support
Refund and chargeback events can be mapped into Credit Notes when the adjustment feature is enabled.
Workflow model
A system-level view of Stripe invoice automation.
The visual model shows how payment events move through validation, persistence, invoice creation and accounting-oriented handoff without exposing the customer to a second charge.
Invoice automation
Payment-to-invoice pipeline.
Webhook security
Signature validation and raw body handling protect payment events.
Incoming Stripe payloads are validated before the service applies business logic.
Accounting handoff
Paid invoices provide the downstream structure bookkeeping tools expect.
The system prepares Stripe invoice records for the external accounting workflow.
Delivery path
A focused delivery sequence for payment automation.
The work moved from payment-flow mapping to webhook implementation, invoice automation, reliability hardening and production-ready operational handoff.
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Phase 01
Payment flow mapping
Map the LearnWorlds, Stripe, invoice and accounting requirements to define the exact automation boundary.
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Phase 02
Webhook and invoice pipeline
Implement Stripe event validation, payment resolution, invoice item creation, finalization and paid status update.
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Phase 03
Reliability and adjustments
Add idempotency controls, processing persistence, refund and chargeback handling, health checks and logs.
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Launch
Deployment and operational handoff
Package the service with Docker, Nginx, TLS, scripts, E2E validation and reprocessing guidance.
Technical direction
Technical structure built for auditable Stripe automation.
The technical direction focused on a backend-only service with secure webhook handling, deterministic invoice creation, database-backed idempotency and containerized deployment.
Fastify
TypeScript
Stripe SDK
Prisma
PostgreSQL
Docker
Project takeaway
“The strongest value of the project was turning payment success into a reliable accounting artifact without creating duplicate charges or duplicate invoices.”
