A set of tools for Belgian companies that keep their books in Odoo
The goal?
- No longer having to migrate or retype your Odoo data into other software in order to draw up your tax returns
- Having reliable reports, which you can check before you send them, to make accountants' work easier
Something needs adjusting? You do it directly in Odoo and regenerate the report until it is right.
Your annual accounts for the National Bank
We prepare your annual accounts as an .xbrl file that meets every requirement of the National Bank, but also as an xlsx file and a pdf that let you check in detail the content you are about to send.
Check whether your Odoo is compatible
How does it work?
The tool reads your database and generates an XBRL ready to download.
We do not keep your data; we have no need to host it for this feature.
The corporate income tax return for the tax administration
Every year you have to file a .biztax file that must satisfy several hundred rules and checks, and attach several PDF files to it.
Our tool prepares that file, taking into account all the regulations in force, and gathers the PDFs in one place.
You can check the result yourself (xlsx and pdf views) before sending it.
Check whether your Odoo is compatible
How does it work?
We copy your accounting data (through an API) into an Odoo instance carrying a module that builds the .biztax file.
Two ways, whichever you prefer: either we host that Odoo instance for you while you prepare your file, and it is downloadable at any time;
or you install the module in your own Odoo and run it yourself. That needs an Odoo you host, or odoo.sh: Odoo Online installs no added module, and that is a constraint of the platform, not a choice.
The migration of your accounting
Our tool lets you migrate your accounting from Odoo 17, 18 or 19 to version 19: into a database we host, onto your own server, or onto your standard Odoo Online (a database whose license you pay for at Odoo's own rate). An older version? Write to us.
The lightest takeover — chart of accounts, balances, investment lines — is free.
The diagnosis is free and commits you to nothing. For what comes after, here is what it costs.
Why we built these tools
This project started with Charbon, a company that has been using Odoo for years and that crosses, every year, the gap between books properly kept in Odoo and the laborious work still needed afterwards to file the tax returns.
Two big needs came out of it:
For filing the annual accounts
The standard XBRL export translates booleans into the user's language. You get faux instead of false, and the filing is blocked. It also breaks addresses on an apostrophe, replaces the general meeting date with today's date, and leaves out the statement of fixed assets. You often only notice at the last minute, close to the deadline.
Our intention was to build a tool that heads off these problems upfront, with clear and specific error messages.
Declaring corporate income tax
Odoo does not produce it at all. The only XBRL it generates is the one for the annual accounts. On the corporate income tax side, it offers nothing but a checklist.
Accountants come up with all sorts of strategies to move the figures into other software, when the data is already "almost ready" in Odoo.
So we built a tool that goes the last mile!
What you remain responsible for
We would rather say it before you buy than after.
These modules prepare files. They do not check your accounting and do not guarantee that your data is correct. A module reads what is in your Odoo. If the accounting is wrong, the file will be wrong too, and it will be wrong tidily.
Proofread every filing before you submit it. Line by line, with your accountant. A generated file is not a checked file, and the amounts at stake can be very large.
You alone are responsible for what you file. Our liability cannot be engaged.
Nothing guarantees this will still work next year. The tax administration and the Central Balance Sheet Office change their formats and their checks every year. We follow, but we make no commitment about the future.
How we work
We cannot guarantee your figures. We can tell you how the modules are tested.
Compared against accepted filings
We regenerate a financial year already filed and accepted by the Central Balance Sheet Office, then compare fact by fact. As long as one difference remains, it is not done.
Checked with Arelle
Using the authorities' official formulas, which are the same arithmetic checks the Central Balance Sheet Office and the tax administration run on your filing.
A negative amount gets named
A balance on the wrong side gets a filing refused. The module names it, account by account, so you reclassify it in your entries. Never disguised inside the XML.
What we do not do
Each one states its limits. That is what makes the rest believable.
BNB produces a base, not a finished filing
The list of directors, the detailed social balance sheet and several notes are entered on filing.cbso.nbb.be. The module tells you which ones.
BNB states its filing models
Its notes are validated on the models it announces. On the others it degrades cleanly rather than silently injecting a wrong value.
Biztax states its tax year
Assessment year 2026. Tax law changes every year and the module follows, but that is not a promise.
Belgian accounting only
Abbreviated and micro schemes. These modules are useless outside Belgium and we would rather say so before you buy.
Fiscal categories don't survive a 17 or 18 detour
You set your account prefixes again, and the delivery screen tells you which.
If it does not work with your data
No two sets of books look alike. If you bought BNB or Biztax and it does not go through with your data, write to us.
Export a snapshot of your accounts with Anthracite IO (it is free) and send it over. From there, two possible outcomes: either we adapt the tool to your data, or we show you what is blocking in your data so you can fix it yourself.
In every case, we will never file on your behalf. We do not promise to succeed every time either. When we do, the fix ships in the next version and benefits everyone.
Who writes this
Anthracite Brussels is the software brand of Charbon Cinéma, a film post-production lab in Brussels. Our day job is picture and sound: mastering, DCP, restoration.
We have been using Odoo since before Odoo, back when it was still called OpenERP.
We keep our books in it, and every year we file our own annual accounts with the National Bank and our own returns in Biztax. These modules came out of a need, ours. We wrote them because we needed them, and they run on our own filings before they are sold.