E-commerce accounting — online stores and marketplaces
We keep accounting for companies that sell online: in their own store, on Allegro, Amazon or other platforms. If you do not sell online, a better page is the one about accounting for companies.
We connect sales through BaseLinker or the store API, handle KSeF and settle VAT OSS. Leave a request and we will explain the integration and the cost of service.
Jeśli sprzedajecie z Polski jako obcokrajowcy i potrzebujecie legalizacji pobytu, tym zajmuje się MIA Legal practice.
How much online store accounting costs
E-commerce accounting packages
UP TO 10 INVOICES
Accounting support
KPiR / revenue records
Monthly and annual reports
HR administration – 50 zł / employee
UP TO 20 INVOICES
Accounting support
KPiR / revenue records
Monthly and annual reports
HR administration – 50 zł / employee
UP TO 30 INVOICES
Accounting support
KPiR / revenue records
Monthly and annual reports
HR administration – 50 zł / employee
UP TO 50 INVOICES
Accounting support
KPiR / revenue records
Monthly and annual reports
HR administration – 50 zł / employee
UP TO 10 INVOICES
Accounting support
Full accounting
Monthly and annual reports
HR administration – 50 zł / employee
UP TO 20 INVOICES
Accounting support
Full accounting
Monthly and annual reports
HR administration – 50 zł / employee
UP TO 30 INVOICES
Accounting support
Full accounting
Monthly and annual reports
HR administration – 50 zł / employee
UP TO 50 INVOICES
Accounting support
Full accounting
Monthly and annual reports
HR administration – 50 zł / employee
* The monthly cost of accounting is based on how many documents you have.
How e-commerce accounting works
E-commerce accounting at MIA CONSULT GROUP is a separate service for online stores and sellers on platforms. It differs from ordinary company bookkeeping in the number of documents and how they are processed.
A store issues anywhere from several dozen to several thousand documents a month: orders, commissions, refunds, ads and corrections. On top of that come KSeF, VAT rates on Allegro and sales to the European Union. If every document is entered by hand, the cost of service rises quickly.
That is why we connect sales to accounting through BaseLinker, an API and MIA BIZNES. The accountant checks the entries instead of retyping every invoice by hand.
Online store accounting
Store and platform invoices, KSeF, VAT and payroll are kept in one place, around that sales activity.
Contractual liability
The business is insured. We are responsible for the quality of our work under the contract.
Over 2,000 entrepreneurs
Including stores and sellers on platforms. We communicate in Polish, Russian and English.
If you need HR service for a warehouse or store operations, we can handle it under the same cooperation, alongside the books and VAT. Leave a request on this page or write via Kontakt.
For invoices, KSeF and tasks for the accountant there is the MIA BIZNES — the same panel we use for e-commerce.
MIA BIZNES
- Free and fast registration
- Full KSeF integration
- AI assistant
- All questions can be handled online
MIA BIZNES business app
MIA BIZNES application
Download it and manage your business conveniently. Don't miss important events, stay mobile. All the features are now at hand in one app.
Available on the App Store and Google Play.
How store accounting differs from ordinary company bookkeeping
A typical B2B company may have a few dozen invoices a month. An online store often has hundreds or thousands of orders, plus platform commissions, refunds and corrections.
If every order is entered by hand, the bill grows with sales. That is why we base e-commerce accounting on a sales export from the store panel, not on PDF files sent by email.
How many documents a store generates
Example: a B2B company with 15 sales invoices and 15 cost invoices is about 30 documents. A store with 50–100 orders a day already means 1,500–3,000 transactions a month — before Allegro commissions, ads and refunds.
Every order is a sales document. Without a connection to the store, someone has to enter it by hand. At that volume, a “per document” price is inconvenient for both the firm and the store.
KSeF and store invoices in 2026
KSeF (the National e-Invoice System) in 2026 is the standard for B2B sales: the invoice goes to the Ministry of Finance system as an XML file, not as a PDF sent by email.
For a store with hundreds of documents a day, uploading invoices by hand in the ministry portal is not practical. We send sales invoices from your channel to KSeF from the accounting system.
Automation: BaseLinker, API and KSeF
At MIA CONSULT GROUP we build e-commerce accounting on the MIA BIZNES platform and a connection to your store.
Sales data are not retyped from every order. They come from your panel (BaseLinker or the store API) into the books and — where required — into KSeF. The accountant checks the postings, rates and exceptions.
Full KSeF integration
System MIA BIZNES is connected to KSeF.
The platform prepares sales data in the required XML format, sends them to the National e-Invoice System and stores the KSeF numbers with the postings. You do not need to do this by hand in the Ministry of Finance portal.
How we send invoices to the accountant
Instead of downloading files from the store at the end of the month, we set up a direct connection between the sales platform and the accounting system.
There are two ways to send the data:
Integration through our own MIA BIZNES API
If the store runs on its own software, we provide secure keys to our API.
After an order is paid, sales data go into our database and into KSeF. The accountant checks the automatic postings.
BaseLinker integration with accounting
BaseLinker brings together Allegro, Amazon, eBay, Shopify and WooCommerce in one panel. If you use it, the connection looks like this:
- We connect the app to your BaseLinker account with an API key.
- The system pulls the sales registers, buyer data and VAT rates.
- The data go through MIA BIZNES, including a check for KSeF.
- Invoices land in the accounting software without manual file-by-file imports.
The service does not depend on whether there were 200 or 2,000 orders in the month. The volume of data changes, not the hours of manual entry.
What e-commerce accounting includes
STORE AND PLATFORMS
We keep accounting for online sales: your own store, Allegro, Amazon and other channels.
BASELINKER AND API
We connect BaseLinker or the store's API to MIA BIZNES. The accountant checks the postings, does not retype orders from PDFs.
KSEF AND VAT OSS
We send sales invoices to KSeF from the system. We settle EU sales under the VAT OSS procedure and file the VIU-DO return in Poland.
CONTRACT AND INSURANCE
We work under a contract and the business is insured. Warehouse and store-staff payroll can be kept together with the books.
Who this service is for
We take on limited companies (sp. z o.o.) and sole proprietors (JDG) that sell online: in their own store, on Allegro, Amazon or another internet channel.
If you do not run a store or sell on platforms, the right pages are accounting services for companies or full accounting.
Allegro accounting
Allegro accounting is not only a list of orders. Commissions, Allegro Smart, Allegro Ads, PayU / Przelewy24, refunds and corrections must be posted to the right accounts.
On Allegro, commissions, Allegro Smart and ads are deducted from revenue. We separate these amounts: the incoming payment is matched against the sales report, and cost invoices from Allegro Sp. z o.o. (including from KSeF) are recorded as expenses.
- Settlements (PayU / Przelewy24): what has come in must match sales after deductions.
- Refunds and corrections: corrections go to KSeF and the tax base drops — you do not pay PIT/CIT or VAT on cancelled transactions.
Amazon accounting (Poland and EU)
Amazon (FBA and FBM) works differently from Allegro. Goods in a warehouse in Germany or France must be shown in the VAT records when they move between EU countries. Amazon often collects VAT on the sale itself — in that case we do not add the same tax again in the Polish return.
- Stock movements: with Pan-European FBA we report goods movements between EU countries.
- VAT collected by Amazon: we report the transactions in line with Polish records, without taxing the same sale twice.
Own store: Shopify, WooCommerce, PrestaShop
For Shopify, WooCommerce and PrestaShop we set up a transaction export through the API — without a manual CSV dump at month-end.
For goods imports (including from China) we settle customs clearance and SAD / PZC documents together with store sales.
Taxes in e-commerce
A store connection does not replace tax filings. We handle VAT, OSS, cash registers and JPK so the store is ready for a KAS inspection.
VAT settlements and cash registers
For B2C sales in Poland, the cash-register exemption for e-commerce often applies — subject to cashless payments and linking each payment to an order. We keep these conditions in check so that you do not have to install a cash register where the law does not require it.
VAT OSS settlements in Poland
Sales to consumers in other EU countries (Czechia, Germany, France…) are subject to the EU distance-selling threshold of EUR 10,000. Once you exceed it, you charge VAT at the rate of the buyer's country.
You do not need to set up a company in every country. We register you for the VAT OSS procedure: the store applies the right rate (e.g. 19 percent for DE), MIA BIZNES collects the data, and once a quarter we file the VIU-DO return with the Polish tax office. One transfer — the office splits the tax between the member states.
What we actually do for a store
When choosing an accounting firm for e-commerce, what matters is whether it handles an online store — not only a general price list for companies. You can estimate the amount for a known number of documents in the accounting price calculator.
Pricing fitted to the store
We do not price e-commerce accounting like manual bookkeeping with twenty invoices. The price depends on the store’s processes, not on how many orders someone retypes.
KSeF from the accounting system
We send sales invoices to KSeF from MIA BIZNES and the store integration. You do not have to upload XML files by hand.
Platforms and your own store
Allegro, Amazon, Shopify, WooCommerce — commissions, FBA, ads and refunds are posted in one set of books.
Data in MIA BIZNES
Invoices, tasks for the accountant and KSeF are in one panel. We do not collect documents from an inbox once a month.
HR and taxes alongside the store
Warehouse, operations, contracts — HR can be run together with e-commerce accounting. Languages: Polish, Russian, English.
How to start: four steps
We plan the move of store accounting to MIA CONSULT GROUP so sales can continue: channels and volume first, then the contract and a BaseLinker or API connection.
Summary
In 2026, e-commerce accounting means connecting sales to the accounting system, KSeF and platform settlements — not sorting PDF files by hand. MIA CONSULT GROUP provides this service for stores and online sellers, with the MIA BIZNES app. We can speak Polish, Russian and English.
Leave a request or write via the Kontakt. If you are moving your accounting from another bureau, it is also worth checking the first month when switching bureaus.
Client reviews
If your question is not on this list, write via Kontakt or leave a request on this page.
Frequently asked questions about e-commerce accounting
Is this accounting for every limited liability company?
No. This page is only for companies that sell online. If the company has no store and no platform sales, you need accounting for companies.
Do you handle sole proprietors (JDG) with an online store?
Yes. We serve sole proprietors (JDG) and companies as long as there is online sales in their own store or on a platform. The legal form itself does not rule out this service.
Do I have to use BaseLinker?
No. BaseLinker is the most common way to connect sales, but own stores on Shopify, WooCommerce and PrestaShop can also be connected through the MIA BIZNES API.
Do you handle KSeF?
Yes. We send e-commerce sales invoices to KSeF from the system, not by hand from the Ministry of Finance portal. This is part of the service.
Can I have Allegro, Amazon and my own store at the same time?
Yes. Most of our e-commerce clients sell in several channels, and we keep the books and JPK together, in one set.
Do you settle VAT OSS?
Yes. After the 10,000 EUR threshold we charge VAT at the consumer’s country rate and file the VIU-DO return in Poland. You do not need a company in every EU country to sell to Czechia or Germany.
Which languages can we use?
The online-store accountant replies in Polish, Russian and English. We discuss Allegro, Amazon or BaseLinker reports and the VAT OSS return in the same language.
