InkVoice — XRechnung & E-Invoicing

Converts between net, tax and gross for a given VAT rate, in either direction. Give an amount and say whether it is net or gross, and you get all three figures back rounded to the cent. Germany's rates are 19 % (standard) and 7 % (reduced), but any rate from 0 to 100 is accepted, so this also works for an Austrian or French invoice. Rounding is half-away-from-zero, the convention invoices and tax authorities use, and the three returned figures always reconcile: net plus tax equals gross exactly, with no cent left over from rounding each separately. What this does NOT do: it does not decide which rate applies to a supply, handle more than one rate at a time, or know anything about reverse charge, intra-community supply or the Kleinunternehmer rules. It is arithmetic, not tax advice.

Builds a German XRechnung 3.x electronic invoice (EN 16931, CII syntax) from invoice details and returns the XML as text. This is the format German public-sector buyers are legally required to receive, and that many private B2B buyers now ask for. The EN 16931 business rules are checked before anything is built, and a rejected call comes back naming the rules that failed and the business term (BT-xx) each concerns. The ones worth getting right up front: tax category S requires a rate above 0 %, categories Z, E and AE require exactly 0 %, E and AE additionally require a stated exemption reason (BT-120), and both parties need an email address because XRechnung makes the electronic address (BT-34, BT-49) mandatory. For a public-sector buyer, put their Leitweg-ID in buyerReference (BT-10) — c

Checks a German Leitweg-ID — the routing identifier that goes in BT-10 of an XRechnung to a public authority. An invoice to a German public body with a wrong or missing Leitweg-ID is rejected, so this is worth checking before building a document. It verifies the structure (Grobadressierung of 2 to 12 digits, an optional Feinadressierung of up to 30 alphanumerics, then two check digits) and recomputes the ISO/IEC 7064 MOD 97-10 check digit, the same procedure an IBAN uses. When the check digits are wrong it returns the ones the address parts actually imply, so the value can be corrected rather than merely rejected. It also names the Bundesland the leading two digits point at, or Bund for the federation. One real limit: the check digit is computed over the address parts with the hyphens re

Reads an existing electronic invoice and reports what is wrong with it. Accepts XRechnung and ZUGFeRD XML in either EN 16931 syntax — CII (used by XRechnung and ZUGFeRD) and UBL — and reports the syntax and profile it found along with the invoice's key fields, so it also answers "what is this file?". It checks the rules behind most real rejections: BT-10 buyer reference present, and its Leitweg-ID check digit when it looks like one; BT-34 and BT-49 electronic addresses present; tax category S not used at 0 %; BT-120 exemption reason present for categories E and AE; line amounts summing to BT-106; net plus tax equalling the BT-112 gross; BT-115 amount due matching gross less prepaid; and the due date not falling before the issue date. What this does NOT do: - It is NOT the KoSIT Prüftool