Odoo keeps your books.
Anthracite gets them ready to file.
Three modules, in the order things actually happen: take over a set of books, file the annual accounts with the National Bank, then declare corporate income tax.
They do not replace your accountant. They save your accountant days.
Between "the books are kept" and "the legal obligations are met", there is a gap.
Every Belgian company crosses it alone, every year.
1. Take over a set of books
Moving to a clean database, splitting one company out of a multi-company instance, taking over a file from a colleague.
Today that means SQL or a consultant.
2. File the annual accounts
The standard XBRL export translates booleans into the user's language. You get faux instead of false and the filing is refused. 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 find out inside Filing, three days before the deadline.
3. Declare corporate income tax
Odoo does not produce it at all. The only XBRL it generates is the one for the annual accounts. On the tax side it offers nothing but a checklist.
Every year you pay again to have your books translated into Biztax.
Three modules
In the order it gets done: take over the books, file the annual accounts, declare the tax. No suite, no platform. All on the Odoo Apps Store.
1. Anthracite IO
Move a set of books in a single file.
- Readable, auditable xlsx export: chart of accounts, trial balance, open items, contacts
- An import that rebuilds everything into one single opening entry
- The entry stays in draft until you post it yourself
- Round-trip checked to the cent: export, import and re-export produce an identical file
You start out on correct opening balances. The detailed history does not follow. It is also how you send us a snapshot of your accounts if another module gets stuck.
Free, and open source (LGPL-3)
2. Anthracite BNB
An XBRL the Central Balance Sheet Office accepts.
- Fixes the booleans the standard export translates (faux instead of false), which block the filing
- Repairs addresses broken by an apostrophe or a hyphen
- Asks for the real general meeting date instead of using today's
- Adds the statement of fixed assets, with revaluation surpluses in their own column
It produces a base. You then complete it on the Central Balance Sheet Office tool, filing.cbso.nbb.be.
349 € on the Odoo Apps Store
3. Anthracite Biztax
The corporate income tax return, importable as is.
- Reserves broken down box by box, disallowed expenses account by account
- Form 275U classified entry by entry, liquidation reserve, rental annex 270 MLH, embedded PDF annexes
- The whole tax cascade, including the basket
- Internal validators that replay the official arithmetic rules before producing the file
Careful: on Biztax, a return that passes validation is submitted automatically. Read the box further down.
469 € on the Odoo Apps Store
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.
On Biztax, loading a valid return means filing it.
There is no separate validation step. As soon as a return passes the checks it is submitted automatically, and there is no going back.
That is why Anthracite Biztax also produces a deliberately blocked test file. It is identical to the real one down to the cent, but guaranteed to be rejected. Biztax hands you its full error report without anything being filed.
That gives you a real validation environment. It does not excuse you from having the content proofread.
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 the modules do not do
Each one states its limits. That is what makes the rest believable.
IO does not carry your history
It rebuilds your balances into one opening entry. You start out correct to the cent, but your past entries and attachments stay behind. The full list of what it leaves behind is explicit, in the documentation and in the file itself.
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.
Odoo 19, on-premise and odoo.sh
A paid module cannot be installed on Odoo Online. That is a platform constraint, not a choice.
Belgian accounting only
Abbreviated and micro schemes. These modules are useless outside Belgium and we would rather say so before you buy.
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 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.