A separate invoice mailbox alongside Peppol: why we recommend it
Quick recap: what does Peppol actually do?
Peppol is the network through which businesses and governments exchange structured electronic invoices, going straight from one accounting package to another through a recognized access point. Since 1 January 2026, this has been mandatory for B2B invoices between Belgian VAT-registered businesses: emailing a loose PDF file no longer counts as a legal invoice, and continuing to do so risks a fine.
It's worth realizing that Peppol isn't an email system. The invoice travels as a structured file (Peppol BIS, based on the European standard EN 16931) from software to software, bypassing your inbox entirely. As a business owner you often see very little of it: your accounting package shows the result, not the transport. For the exact rules, exceptions and fines, see the official government sources below; what we give here is general explanation, not tax advice.
Why we still recommend a separate invoice mailbox
Even with a working Peppol connection, there's still email traffic around invoices. Think of a freelancer from the Netherlands or France who isn't on the network yet, a credit note, a quote, or a parking receipt. Those simply arrive as a PDF, and you don't want them landing in the same inbox as newsletters and unsolicited job applications.
There's something else at play too: many accounting packages, such as Yuki, Billit, Exact Online or Odoo, already come with their own scan or import address where you send invoices for processing. Handy, but that address belongs to your software vendor, not to you. Switch to a different package or access point one day, and you lose that fixed point of contact. Manage your own facturen@jouwbedrijf.be on your own domain, and that address, along with the archive behind it, simply stays yours, whatever your software does.
One last, practical advantage: giving access. A bookkeeper or file manager can freely look through the invoice mailbox without needing to poke around in your entire general inbox.
How do you set up an invoice mailbox?
In practice it comes down to five steps:
- Create the address on your own domain. For example
facturen@jouwbedrijf.be, either as a full mailbox or as a lighter alias. You can read exactly how that works in creating an alias. - Connect it to your accounting package. Set up a forwarding rule to the scan or import address of your accounting software or access point, so incoming invoices land there automatically. You won't need to forward anything by hand.
- Only give access to who needs it. Your bookkeeper logs into this one mailbox, not your general business inbox.
- Build your own archive. Alongside whatever your access point or accounting package keeps, you maintain an organized overview in this mailbox that stays yours. See also email archiving and retention periods.
- Give the address extra protection. A mailbox that mostly receives attachments from outsiders is a favorite target for fake invoices. Good filtering and knowing what to watch out for (see recognizing phishing) belong in the mix.
Where things sometimes go wrong
One thing we want to make clear: an invoice mailbox doesn't replace your Peppol obligation. It's a safety net for whatever else still comes in by email, not a way to sidestep the mandatory, structured exchange. And exactly how long you need to keep invoices differs by document type and situation. That's best discussed with your bookkeeper rather than relying on a rule of thumb.
The two practical pitfalls we see most often: an invoice mailbox that nobody actually monitors, so it just turns into a dumping ground, and an address where too many people log in with a shared password. Assign one owner, turn on 2FA, and treat the address with the same care as your banking details, because fraudsters have caught on that "facturen@" is an appealing target too.
And at Mailflux
Let's be clear: Mailflux isn't an accounting package or a Peppol access point. We take care of the mailbox infrastructure alongside it. On your own domain you can set up a separate mailbox or alias for your invoices in a few minutes; working with multiple staff or branches, you create and manage those accounts in bulk instead of clicking through them one by one.
Every plan runs with antispam, antivirus and ML-driven antimalware by default: exactly what you want on an address that receives attachments from strangers all day long. Automatic backups also keep your invoice history intact, separate from whatever your accounting package itself retains. Storage ranges from 8 GB on Basic to 50 GB (expandable to 100 GB) on Premium, plenty for years of invoices in PDF.
Work in accounting, or run an SME? Also check out email for accountants or email for SMEs.
Get started
In short: Peppol handles your mandatory B2B exchange, but keeping a dedicated invoice mailbox alongside it gives you a clear overview of everything else. Want one on your own domain? Request your mailbox with no obligation and it's set up in a few minutes.
FAQ
Frequently asked questions
Does an invoice mailbox replace my Peppol connection?
No, and that's a misunderstanding we hear a lot. Peppol handles the mandatory, structured exchange of B2B invoices directly between software through an access point. An invoice mailbox catches what falls outside that, such as foreign suppliers, credit notes or receipts, or serves as a relay to the scan address of your accounting package.
Does every business already have to work with Peppol?
Since 1 January 2026, the requirement applies to B2B invoices between Belgian VAT-registered businesses, with limited exceptions. Whether and how exactly that applies to your business is best discussed with your bookkeeper or checked through the official government sources. What we give here is general explanation, not tax advice.
Can I automatically forward incoming invoices to my accounting package?
Yes, that's exactly what makes it handy. You set up a forwarding rule on your invoice mailbox to the scan or import address of your accounting package or access point, and invoices land there without you having to forward them yourself.