What does website and accounting integration mean?
To integrate your website with accounting software in Thailand, you connect your online shop or booking pages to your accounting system so orders, payments and customer details arrive automatically, instead of someone copying them from one screen to another.
In practice that usually means connecting WooCommerce or Shopify to a local cloud accounting tool such as FlowAccount or PEAK, so each paid order becomes a sales document with the right customer, amounts and VAT.
The simplest version is a monthly export file your bookkeeper imports. The most complete version is a direct connection that creates documents the moment an order is paid. Most Thai small businesses land somewhere in between, and the right point depends on order volume, not on ambition. Plan this early: if you are still mapping out the site itself, follow a step-by-step build guide and note the accounting link as a requirement from day one.
What data should flow, and in which direction?
Retyping causes three problems: typing errors in amounts and tax, invoices issued late or twice, and a month-end close that takes days of matching bank lines to orders. Before choosing a tool, list what should move and which system is the master for each item.
- Orders (website to accounting). Each paid order becomes an invoice, receipt or tax invoice, with line items, discounts, shipping fees and VAT.
- Customers (website to accounting). Name, address and, for business buyers who want a full tax invoice, the company name, branch and 13-digit tax ID. Your checkout needs fields for these.
- Payments (website to accounting). How the order was paid, card, PromptPay, bank transfer or COD, so it can be matched against the bank or gateway payout.
- Refunds and cancellations (website to accounting). Credit notes that reverse the original document, never silent deletions.
- Stock (usually one direction only). Decide whether the shop or the accounting system holds the stock count. Syncing both ways invites conflicts.
COD orders deserve special care. The courier collects the cash and pays you later, minus fees, so the order, the delivery and the remittance happen on different days. Agree with your accountant when a COD sale is recorded.
Four ways to connect, from simple to custom
1. CSV export and import
Export orders from WooCommerce or Shopify as a spreadsheet file and import it into the accounting tool on a schedule. It costs almost nothing and suits a shop with a few dozen orders a month, as long as someone checks the column mapping each time.
2. Ready-made connectors
Some accounting tools and store platforms offer apps or plugins that link the two. Where one exists for your pair of systems, it is usually the best value. Check what it syncs, especially refunds and tax, and who maintains it.
3. Middleware
Automation services such as Zapier or Make watch for a new order and create a document in the accounting tool, without custom code. They charge by usage, and multi-step flows with refunds or many line items can get fiddly.
4. Direct API
A developer writes a small connection that uses both systems' APIs. It gives full control over mapping and error handling, and needs the most testing and upkeep.
| Route | Set-up effort | Running cost | Speed of sync | Good fit |
|---|---|---|---|---|
| CSV export/import | Low | Staff time | Daily to monthly | Low order volume |
| Ready-made connector | Low to medium | Licence or app fee, if any | Near real time | When one exists for your two systems |
| Middleware | Medium | Usage-based subscription | Minutes | Moderate volume, simple orders |
| Direct API | Higher | Maintenance time | Real time | High volume or unusual tax and document rules |
Which Thai accounting software has an API?
Two Thai cloud accounting tools publish developer documentation for connecting other systems, which is the first thing to check before any integration plan.
- FlowAccount offers an OpenAPI with developer documentation, covering the creation of sales documents such as quotations, invoices and receipts.
- PEAK offers an API for connecting outside systems, with its own developer pages and access process.
Access terms, which plans include API use, and the exact endpoints change over time, so read each provider's current developer pages and ask their support before you commit. International tools such as Xero or QuickBooks also have APIs and large connector ecosystems, but check how they handle Thai tax documents and Thai-language output before choosing one for a Thai company.
On the website side, WooCommerce stores every order in your own WordPress database and exposes it through its REST API, which gives a developer full access to line items, tax lines and customer fields. That is one reason WooCommerce is popular with Thai sellers who want control, as our article on WordPress in Thailand explains. Shopify, the hosted store platform, also exposes orders through its API, with tax and payment details recorded per order.
e-Tax invoices and your website
The Revenue Department runs the e-Tax Invoice and e-Receipt system, which lets VAT-registered businesses issue tax invoices and receipts electronically instead of on paper. Businesses join by applying to the Revenue Department, and there is more than one way to issue documents, including routes aimed at smaller businesses. The conditions and application steps are on the Revenue Department's e-Tax site, and your accountant should confirm which route applies to you.
Where does the website fit? In most setups the website does not issue the legal tax invoice itself. It collects the right data at checkout, passes the paid order to the accounting software, and the accounting software, set up for e-Tax, issues the document and sends it to the customer. That makes the checkout fields important: a business buyer needs a way to enter a company name, head office or branch number, and tax ID, and a consumer should not be forced to fill them in.
Our E-commerce package, from THB 50,000 as an indicative one-time price, includes e-Tax invoice setup alongside PromptPay, cards, COD, Thai couriers, product import and staff training. The final scope is set in your written quote.
Testing, PDPA and upkeep
Test in a sandbox first
Never point a new integration at your live books on day one. Use a test company or sandbox account in the accounting tool where the provider offers one, and a staging copy of the shop. Run a checklist of real cases: a normal order, an order with a discount code, a shipping fee, a COD order, a partial refund, a full cancellation, and a business buyer asking for a full tax invoice. Have your accountant review the resulting documents before you switch over.
Customer data and PDPA
Sending customer names, addresses and tax IDs to an accounting tool or a middleware service means sharing personal data with a data processor. Under the PDPA you should name those services in your privacy notice, have a data processing agreement or suitable terms with each, and only send the fields the accounting side needs.
Keep it running
APIs change versions, access tokens expire, and a plugin update can alter a field name. Set up an alert for failed syncs and have someone check a short weekly report. Our wider guide to API integrations for business websites covers monitoring in more depth. Be wary of tools promising that automation will run your books unattended; our piece on AI in website development helps you judge such claims.
Planning your integration
Start with your accountant, not with a developer. Agree the chart of accounts, the tax codes for VAT and zero-rated items, how shipping and discounts are posted, and when cash on delivery (COD) sales are recognised. Only then map fields between the systems. A connection built on the wrong mapping just creates wrong documents faster.
Next, fix the payment side, because reconciliation depends on how payouts arrive. If you sell on Shopify, our guide to choosing a payment gateway for Shopify in Thailand explains the options. For WooCommerce shops, the walkthrough on how to build a WordPress website shows where checkout fields and plugins are set up.
As part of our web development for business, we can set up the link between your store and your accounting tool inside the website build, using an existing connector or a middleware service where one fits, with the exact scope agreed in your quote. We do not build custom accounting software or standalone web applications. A typical project takes about 15 days, while large catalogues or complex integrations can take longer, and we will say so in the quote. For budgets, see our page on WordPress website cost.
More on WordPress and platforms
Sources
- FlowAccount OpenAPI developer documentation
- PEAK API for developers
- Revenue Department: e-Tax Invoice and e-Receipt
- WooCommerce REST API documentation
- Personal Data Protection Act B.E. 2562 (2019), English translation
Builds and ranks the websites: the systems behind the 17 client sites whose Search Console numbers we publish. This guide was written by the Website Development Bangkok team. More about us