e-Materai

SaaS platform for electronic stamp duty (e-Materai) in Indonesia. Guests stamp without registering, quota survives a failure, and a free PDF tool suite brings in the users.

The problem

Existing e-Materai services forced registration before the user had seen anything, charged quota before they knew whether stamping would succeed, required manual X/Y pixel entry for the stamp position, and offered no PDF tooling at all. Users who failed burned quota they had already paid for.

What I did

• Led backend development on a Laravel 13 monolith built around explicit service classes.
• Implemented a two-phase stamping flow: free validation with a visual mockup first, then a transactional phase that only decrements quota after a serial number is successfully issued.
• Made quota decrement atomic with SELECT ... FOR UPDATE and rolled back plus logged a refund on any downstream failure, so a failed stamp never costs quota.
• Integrated Peruri for serial numbers and signing, Midtrans for QRIS/VA/GoPay with webhook signature verification, and a Dockerized on-prem sign adapter.
• Validated uploads by magic bytes and scanned them with ClamAV; ran document conversion through LibreOffice, FPDI, and Ghostscript.
• Shipped 8 free unlimited PDF tools, which cost CPU but almost no marginal money and became the top-of-funnel acquisition path.

Impact

62

commits as software Engineer

8

free PDF tools shipped

0

quota lost on failed stamping

Stack

• Laravel 13
• PHP 8.3
• Livewire 4
• Octane
• MySQL
• Redis
• MinIO
• Docker
• Midtrans
• Peruri
• LibreOffice
• FPDI
• ClamAV
• Tailwind