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Selected work

Full-stack/2025/Production

Payment Voucher System

Lets an organization raise, approve, and pay supplier vouchers through an approval chain you can configure to however many signatures you need. It works out Ghana/GRA tax, prints the official PDF slips, and keeps a record of every step that nobody can quietly go back and edit.

Context

Any organization paying suppliers against approved vouchers needs tight control and a clean paper trail: approvals nobody can skip, tax worked out correctly, and a record that cannot be quietly changed after the fact.

Approach

  • 01Implemented a configurable multi-signature approval workflow (one to five steps) as an explicit state machine.
  • 02Computed Ghana/GRA tax and generated official PDF voucher slips with OpenPDF.
  • 03Scoped all data per company for multi-tenancy and kept an immutable audit trail of every action.
  • 04Built on Spring Boot and PostgreSQL with Flyway migrations, secured with JWT, CSRF protection, and account lockout, and covered by a Mockito test suite.

Notable

  • Fintech-grade security: JWT, CSRF, and account lockout by default.
  • Compliant tax computation and official, printable voucher slips.
  • Immutable, audit-ready record of every approval.

Next project

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