VAT reverse charge B2B: charging 0% with VIES
Selling to a VAT-registered business in another EU country is one of the few cases where charging 0% VAT is fully compliant — but only when specific conditions all hold at once, and only if you can actually prove the decisive one. The mechanism is called reverse charge: instead of you collecting VAT and remitting it, the liability shifts to the buyer, who declares it on their own return. Get it wrong in one direction and you've undercharged VAT you owed; in the other, you've turned down a legitimate 0% sale out of caution.
What "reverse charge" actually means
In a normal domestic sale you charge VAT on the invoice, collect it, and remit it to your tax authority. Reverse charge flips the responsibility: you invoice the net amount with no VAT added, and the buyer declares the VAT themselves — as a purchase they can typically reclaim and, mechanically, as a sale they owe, which nets to zero for a fully VAT-recovering business. The tax authority still gets its declaration; it just comes from the buyer's paperwork instead of yours.
What has to be true before you zero-rate
Every requirement has to hold at once — the buyer's status as a VAT-registered business, the genuinely cross-border nature of the sale, and a VAT number you have actually validated rather than merely collected. Fail any one and this is an ordinary VAT-charged sale, not a borderline case. The walkthrough below takes them in the order you can actually check them.
Why the VAT number has to be validated, not just collected
This is where most of the real-world mistakes happen. A VAT number has a predictable shape per country — a two-letter country prefix plus a run of digits (and the odd letter, depending on the country) — so it's easy to write a check that confirms a number is well-formed and easy to mistake that for confirmation that the number is real. It isn't. A well-formed number can still belong to a business that deregistered last month, or never existed at all.
Working through a B2B sale, in order
1
Ask for a VAT number
2
Check the format
3
Validate it live against VIES
4
Confirm it's genuinely cross-border
5
Zero-rate and annotate, or charge VAT as normal
How Olmira handles this
Validating a VAT number is the part of this that's genuinely hard to do reliably by hand — a format that looks right isn't the same as a number VIES actually recognises, and checking by hand for every order doesn't scale. Olmira's tax tools check a buyer's VAT number against the same live VIES service the EU runs: format first, then a real-time VIES lookup, and if VIES itself doesn't answer, the result comes back as unconfirmed rather than a guessed "valid" — so you're not zero-rating a sale on a check that never actually completed. That validator sits in your store's tax settings, next to the EU rate tables the OSS guide covers.
Related guides
EU VAT for online sellers
No. Reverse charge on this basis requires the buyer to be registered in a different EU country from you. A domestic B2B sale is invoiced with VAT as normal, regardless of the buyer's VAT status.
Treat the sale as unconfirmed, not zero-rated. The safe default when a number can't be confirmed is to charge VAT as usual — a genuinely VAT-registered buyer can reclaim it through their own return either way.
No. It's strictly B2B. A consumer purchase — even by someone who happens to run a business — falls under normal VAT rules or the OSS scheme, never reverse charge.
A note stating the supply is subject to the reverse-charge mechanism, so the buyer's own bookkeeping knows to self-account for the VAT. The specific wording expected varies slightly by country; your accountant can confirm the phrasing yours requires.
Check at the start of the relationship at minimum, and re-check periodically — a business can deregister its VAT number, at which point a sale that qualified last year wouldn't qualify today.
No. Reverse-charge rules and VIES itself are run by tax authorities and the European Commission and can change without much notice — confirm anything you're relying on with an accountant before you rely on it.