Accounting system

An accounting system is software where a company keeps its financial and inventory records: sales and purchase documents, stock levels, money in accounts, settlements with counterparties. Reporting and tax data come from it.

In plain words

A store sells on the website, and the accounting system answers the question "what actually happened to the money and the goods": what was sold, what was written off the warehouse, what the customer paid, what is owed to suppliers. The store's admin panel handles orders. The accounting system handles the documents the accountant uses to prepare reports.

Under the Law of Ukraine "On Accounting and Financial Reporting in Ukraine", business transactions are recorded on the basis of primary documents. They can be paper or electronic, but electronic ones are valid only if the legal requirements for electronic documents and electronic document flow are met (zakon.rada.gov.ua, version of 01.04.2026). These are the documents an accounting system helps create and store.

Why an online store needs it

• One truth about stock and money: not "one number in the spreadsheet, another in the warehouse".
• Documents (waybills, acts, reports) are generated from order data instead of being retyped by hand.
• The accountant sees sales by channel and payment system and closes the period faster.
• It gives you a basis for KPIs and margin: cost and profitability are calculated from the accounts.

Exchange with the website

Usually these flow between the store and the accounting system:

• orders and customers — from the site to accounting (to create a sales document);
• stock and prices — from accounting to the site (so a customer doesn't order what isn't there);
• payments — from the payment service and the delivery service (to match money to orders, including cash on delivery);
• fiscal receipts — for sales through a PRRO;
• returns — product returns must reach accounting as a separate document.

The exchange runs through APIs and integrations, file export, or manually. Manual exchange is usually the first thing to break once orders grow.

Ukrainian context

• The accounting law applies to legal entities. Sole proprietors (FOP) follow different accounting rules that depend on their tax system; check them with your accountant.
• Electronic primary documents require an electronic signature or seal as the law prescribes (same source).
• Selling to individual customers through a website comes with a settlement document: see PRRO. The accounting system and the PRRO service must be aligned so that the receipt, the order and the accounting document match.
• Nova Poshta and payment services send money back at different times and with fees: accounting must tell apart the order date, the receipt date and the date the money arrived.

This is not legal or tax advice.

When it is too early

If orders are few and the accountant works from bank statements and spreadsheets, a separate accounting system may not pay off. It starts to help when there are so many documents that manual transfer causes errors.

Accounting system, ERP and CRM

• ERP includes accounting as its core and adds warehouse, purchasing, production and more. An accounting system can stand alone, without the other modules.
• CRM handles customers and sales, not accounting documents.
• Warehouse operations can be handled by a WMS or a warehouse module, while accounting receives the totals.

Common mistakes

• Two stock databases, on the site and in accounting, that don't sync.
• No single order key (the store's number, the payment number and the document number don't match).
• Returns and uncollected parcels are not accounted for.
• A cloud system is chosen without asking about data export.

FAQ

What is an accounting system in plain words? Software where a company keeps documents, stock and money for bookkeeping and reporting.

How is an accounting system different from ERP? An accounting system keeps the books. ERP usually includes accounting and adds warehouse, purchasing and production.

Can a store keep its books in Excel? While orders are few, yes. Later the risk of errors and manual work grows; the limit depends on your volumes and your accountant's requirements.

How does an accounting system connect to the website? Through APIs and integrations or file exchange. See APIs and integrations.

Related terms

• ERP
• PRRO and fiscalization for an online store
• OMS and WMS
• APIs and integrations
• Cash on delivery and unclaimed parcels

Sources

• Верховна Рада України, Закон «Про бухгалтерський облік та фінансову звітність в Україні» № 996-XIV (редакція від 01.04.2026) — zakon.rada.gov.ua/laws/show/996-14

There is no fresh open data on how Ukrainian stores use accounting systems. Sole-proprietor (FOP) accounting rules are not covered here.