Integration in Cambodia.

What does Scale's Integration practice cover?

Scale's Integration practice connects systems never designed to talk to each other (ERP to banking API, e-commerce to inventory, CamInvoice to accounting, factory MES to operations dashboard) using REST, GraphQL, EDI, MQTT, and webhooks, with observability and retry logic built in from the start. We cover mobile, website, system, and API integration, with depth in Cambodia's bank APIs and CamInvoice.

A typical mid-size Cambodian business in 2026 has: an ERP or accounting system; a banking relationship with ABA, Wing, or Bakong to read statements from and initiate payments through; a GDT return whose figures should come out of the system, not out of a manual scramble before each monthly deadline; an e-commerce presence on Shopify, WooCommerce, or a custom storefront that must feed inventory and order data into the ERP; and increasingly a factory or warehouse system generating data that management wants in a single dashboard.

Each connection is a separate integration project, or a well-scoped phase within a larger programme. What separates a well-built integration from a fragile one is three things: the adapter pattern (a clean contract that does not break when either side changes), observability (in real time: is it running, how many records flowed, what errors occurred), and retry strategy (when the downstream system is unavailable, it queues and retries instead of silently dropping records).

How do we approach integration architecture?

Every integration Scale builds follows the same architecture principles: adapter isolation (each system connection is an independent module with a defined contract), observability first (every message logged, every error alerted, every retry tracked), and idempotent design (duplicate messages do not create duplicate records in the target system).

Each adapter takes a message from the source system, validates it, maps it, and submits it to the target system. When a SaaS vendor updates its API between versions, or ABA changes its payment initiation endpoint, only the affected adapter changes; the rest of the pipeline is unaffected.

Observability means every integration ships with a log table recording each message, a monitoring dashboard showing submission counts and error rates, and real-time alerting (Telegram and email) for any message that fails after exhausting its retry queue. Your operations team sees what is flowing, what failed, and why, without calling us.

Retry uses exponential back-off: a failed submission is retried after 1 minute, then 5 minutes, then 30 minutes, then 2 hours, then 24 hours. After five failures the message is parked in a dead-letter queue and an alert is sent. The idempotency check hashes the source record's unique identifier and rejects duplicates before they reach the target system; for CamInvoice, a duplicate submission could put the same invoice on the network twice.

What about GDT and CamInvoice specifically?

They are two different things, and only one has an API. GDT's monthly return is filed by a person through GDT's E-Filing, so what we build for it is the figures, ready to file. CamInvoice is GDDE's B2G e-invoicing platform, launched May 2025, and it has an API we integrate.

For GDT, the system keeps the books in KHR at the NBC daily rate on the invoice date, carries the tax codes (VAT 10%, VAT 0%, VAT exempt, WHT at 15%/10%/14%), and produces the monthly return figures and the sales and purchase lists. Your accountant files them through E-Filing by the 25th of the following month; the system removes the re-keying, not the date. Our GDT e-VAT guide covers the pitfalls.

CamInvoice is newer, more complex to onboard, and affects a narrower set of businesses: those invoicing the ministries and institutions the MEF circulars name. It needs onboarding with GDDE, OAuth 2.0 credentials, invoices in UBL 2.1 XML, and a webhook or polling to learn what the network did with each one. Our CamInvoice integration guide walks through the onboarding; the API integration page covers project structure.