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Invoicing where the work already lives — and every invoice goes out as an e-invoice

Raise itemised, VAT-correct invoices in the same platform that schedules the jobs and holds the paperwork. Issue one and it goes out as a Factur-X e-invoice: an ordinary PDF on the surface, machine-readable underneath.

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The problem it kills

Most invoicing software for water hygiene companies is Word plus the accounts package: the office retypes what the engineer did, works out the VAT by hand, and keeps the next invoice number in a spreadsheet cell someone once made bold. Every retype is a chance to bill the wrong thing, and the whole routine produces a document that's about to feel dated — across Europe, invoices are becoming structured data with rules attached, and a typed PDF carries none of it.

VAT-correct by construction

Each line carries its own VAT code, and the rate follows the code — a zero-rated line can't end up charging 20% because nobody can type a rate that contradicts its code. Mixed-rate invoices get the per-rate summary HMRC expects, computed the way accountants check it: per line, then summed.

  • Per-line VAT codes: standard, reduced, zero, exempt, out of scope
  • Rates derived from codes — impossible to contradict
  • Per-rate VAT summary on mixed invoices, net → VAT → gross

Numbering an inspector can follow

Invoice numbers are allocated by the server at the moment of issue — sequential, no gaps to explain. Drafts carry no number, so an abandoned draft never burns one. Once issued, an invoice is frozen: corrections don't edit history, and a voided invoice keeps its number, which is how you explain a sequence rather than apologise for it.

  • Sequential numbers allocated at issue, never guessed at
  • Issued invoices are frozen — no silent edits after the fact
  • Void keeps the number; the series always accounts for itself

Every invoice is a Factur-X e-invoice

The PDF you issue carries a second, machine-readable copy of itself: the full invoice — parties, lines, VAT breakdown, totals — embedded as structured XML in the EN 16931 format, the European e-invoicing standard, inside an archival-grade PDF/A-3. Your client sees a normal branded PDF. Their accounts software sees data it can ingest without anyone retyping. BlueWave validates that data against the official EN 16931 rulebook, invoice by invoice, before it's embedded. There's nothing to switch on and no per-invoice fee.

  • Factur-X at the EN 16931 profile — the level German and French rules accept
  • Checked against the official European rulebook before it leaves
  • PDF and data rendered from the same totals — they can't disagree

What's owed, at a glance

Three money tiles sit above the invoice list — Overdue, Owed to you, Drafts not yet issued — and each one filters the list to exactly the invoices behind its total. The Overdue tab runs oldest first with days late on every row, and marking an invoice paid records how the money arrived and against what reference.

  • Overdue tab, oldest first, days late on the row
  • Mark paid with method and payment reference
  • Three live totals that open the list they're made of

E-invoicing is arriving with dates attached

Germany has required businesses to accept structured e-invoices since January 2025, with paper and plain PDFs phasing out of issuance from 2027. France's rollout begins in September 2026, and Factur-X is one of the three formats its approved platforms must handle. Belgium went mandatory in January 2026. The UK has confirmed its own mandate for April 2029, network chosen, format still to be named. BlueWave's position is simple: your invoices should start carrying the structured data now, over the channel you already use — a PDF attached to an email. We'll be honest about the boundary, too: a valid e-invoice file is not the same as a connection to any country's clearance network. Nobody sending PDFs has that today. What carries forward is the data discipline, and that's the part already in every invoice you issue.

The other half of billing — quoting remedials the day they're found, and contracts billed as the work completes — lives on the contract billing page.

Common questions

What is a Factur-X e-invoice?
A normal PDF with a structured data file inside it. Your client reads the PDF as usual; their accounts system reads the embedded XML, which carries the same lines, VAT and totals in the EN 16931 format European regulations are built on. One file, readable by both. BlueWave checks that data against the official EN 16931 rulebook before it's embedded.
Do I have to set anything up to get e-invoicing?
No. There's no module to enable, no toggle, no per-invoice fee. Issue an invoice and the PDF that goes out is a Factur-X e-invoice. If your client's systems can't use the structured data yet, nothing changes for them — it's still an ordinary PDF on the surface. One deliberate choice worth knowing: we only ever emit the full EN 16931 profile, because the cut-down profiles some tools produce don't legally count as e-invoices in Germany and are being banned in France. A profile picker would only exist to let someone pick wrong.
Does this cover the UK's 2029 e-invoicing mandate?
Nobody can claim that yet, honestly — the UK has confirmed the mandate and chosen the Peppol network, but the format won't be named until the government's e-invoicing roadmap lands. What we can say: BlueWave invoices already carry their data in EN 16931, the European standard this whole wave is built on, so you're not starting 2029 from a paper process. Structured data is the part that can't be retrofitted; the wire format is the part that can.
Won't our accounting package handle e-invoicing?
Unevenly, and later than you'd hope. Xero can already send e-invoices in the UK, though only between VAT-registered businesses and only where your customer is registered on the Peppol network; the other mainstream packages have shipped little for UK small businesses so far. The durable point is different: a ledger can only e-invoice what's raised in it. If your invoices are raised in the platform that runs the work, the document has to be born structured there — and a Factur-X e-invoice asks nothing of your customer, because it travels by ordinary email and reads as a normal PDF.
What if we're not VAT registered?
Then BlueWave won't let you charge VAT by accident. Until a VAT number is in your settings, every line is forced out of scope and the invoice renders no VAT block at all — charging VAT before you're registered is an offence, so this is a guard, not a default. Once registered, each line carries its own VAT code and the rate follows the code automatically.

Watch an invoice go from draft to issued in a demo

Bring a real one — mixed VAT rates, the lot. We'll raise it live, issue it, and open the e-invoice data hiding inside the PDF.

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Invoicing Software for Water Hygiene Companies | BlueWave