Why gapless numbering matters
In the EU, outgoing invoices need consecutive, verifiable numbers — a series with unexplained holes is a problem in a tax audit. TaxItEasy handles this structurally: numbers are allocated atomically, never reused, and a built-in gap report proves the series is intact.
One thing to be clear about: this applies only to your own outgoing invoices. Numbers on supplier bills you receive are foreign numbers, stored as free text, and live in a completely separate world — your sequences and your suppliers' numbering can never collide.
How sequences are organized
A sequence is defined per company, per document kind, per year. In practice that means your invoices and your credit notes are numbered independently, and each year can start its own series. You don't have to set anything up to begin: the first time you open the Sales page, a default invoice sequence with the prefix RE- is created automatically.
The format is configurable in Settings → Number sequences: prefix, suffix, year format, separator, counter digit count (1 to 10 digits), and an optional yearly counter reset. The drawer shows a live preview that mirrors the real formatter exactly, so what you see there is what your invoices will carry.
Setting a start number
Migrating from another tool where your last invoice was, say, number 2033? Set the sequence's starting number to 2034 and TaxItEasy continues the series seamlessly. Two guard-rails apply:
- The start value must be 1 or higher.
- It can only be changed before the sequence allocates its first number. Once a single number has been issued, the counter — and the entire format — is locked: the fields are disabled in the UI, and the API rejects changes too. This makes it structurally impossible to ever re-issue a number that already exists on a document.
For the same reason, a sequence that has issued numbers can't be deleted — only deactivated (paused).
Atomic allocation — no gaps by design
Drafts show the next available number as a provisional value; the real number is stamped only at finalize. Allocation happens inside a database transaction with row locking, which gives you two guarantees:
- No duplicates, even if two people finalize at the same moment.
- No gaps on failure: if issuing fails midway — for example the PDF can't be rendered or stored — the allocation rolls back and the number is returned unused. A failed finalize never burns a slot.
What happens when you cancel an invoice
Cancelling a finalized invoice does not free its number. The cancelled invoice stays in your records with its number intact — think of it as a tombstone that keeps the slot occupied — and the cancellation document gets its own number from your credit-note sequence. The two are linked and net out to zero. Result: both series stay gapless, and every number in them points at a real, retained document. Details in credit notes and cancellations.
The gap report
Each sequence shows a per-year gap report in Settings. Green means the series is complete. Red means a gap was detected, and the report lists exactly which numbers are missing so you can investigate. The report is informational — there is deliberately no "renumber" action, because renumbering issued documents is precisely what audit-safe numbering forbids.
Who can change sequences
Only company Owners and Admins can create or edit number sequences. Every change is captured in the audit log.
Related
- Create and send an invoice — where the provisional and final numbers appear
- Credit notes and cancellations — how cancellations keep both series gapless
- VAT schemes and VIES validation — the other compliance half of issuing an invoice