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CASE STUDY/Full Stack

DoriPay

PPOB billing and digital product payment platform

GoGoFiberFiberSvelteSveltePostgreSQLPostgreSQLpgxpgxTripayDigiflazzOrkut

Overview

A full-stack PPOB payment system designed for secure, automated online billing and digital product transactions (credit, data packages, electricity tokens).

01 · The Problem

Concurrent wallet transactions can cause race conditions and double-spend on balance mutations during heavy customer traffic peaks.

02 · Decisions & Solution

Idempotent requests plus pessimistic row locking in PostgreSQL, structured with Clean Architecture in Go Fiber and integrated with Tripay and Digiflazz/Orkut APIs.

03 · Impact & Results

TODO_ANGKA — Replace with local load-test or production metrics (e.g. 0 double-spend across N concurrent wallet deduction requests, or number of digital product SKUs supported).

System Architecture

Svelte client dashboard (Svelte Stores), Golang Fiber backend structured in Clean Architecture, PostgreSQL database with high-performance pgx driver, and asynchronous webhook reconciliation.

Svelte ClientSvelte Stores · RBAC UIGo Fiber BackendClean Architecture · ACIDIdempotency Key GuardPostgreSQL (pgx)Pessimistic Row LockingSigned Webhook CallbacksTripay GatewayQRIS · Virtual Account · E-WalletDigiflazz & Orkut APIPPOB Fulfillment Providers

Challenges & Learnings

Engineering Challenge:

Preventing double-spend on instant deductions and handling gateway webhooks reliably. Mitigated by enforcing strict database row locks and request idempotency keys.

Key Takeaway:

Gained deep knowledge in secure financial ledger engineering, Svelte stores state synchronization, and integrating external payment gateway API endpoints.