Guides
Written for the question a developer types, not for the endpoint: what to do when a member state is down, which rate applies where, how the check digits work. Each ends with the call that answers it.
- The VIES API: REST vs SOAP, the error codes and the limits
The European Commission’s VIES API is free and needs no key: REST and SOAP compared, the fields, every error code, the limits, and what to build around it.
Updated 2026-10-28
- VIES is down: how to validate an EU VAT number anyway
What MS_UNAVAILABLE, SERVICE_UNAVAILABLE and TIMEOUT mean, why member states go dark, and the four-step fallback that keeps a checkout or an invoice run going.
Updated 2026-10-24
- EU VAT rates for digital services by country
The VAT rate on SaaS, downloads and streaming in the 27 member states, the e-book exceptions and the OSS rule that picks the rate. Verified 2026-10-24.
Updated 2026-10-24
- Validate EU VAT numbers in Node, Python and PHP
Copy-paste functions for Node.js, Python and PHP that validate an EU VAT number on VIES in one REST call, handle a VIES outage and read the consultation number.
Updated 2026-10-24
- Validate an IBAN: the mod-97 check explained
How an IBAN is built, how the ISO 7064 mod 97-10 check works step by step on a real IBAN, what it catches and misses, and why the BBAN pattern matters too.
Updated 2026-10-24
- Which VAT rate for OSS: the consumption-country rule
Since July 2021, EU B2C distance sales and digital services are taxed at the customer’s country rate. How to pick it per sale and the €10,000 threshold.
Updated 2026-10-24
- API Sirene: what the free government API gives you, and what it does not
INSEE’s Sirene API and the open Recherche d’entreprises API are free. What each returns, their limits (30 a minute, 7 a second) and what neither gives you.
Updated 2026-10-24
- Validate EU VAT numbers in bulk from a CSV: the loop, the pacing, the evidence
A CSV of VAT numbers in, a dated results file out: de-duplicate, check the structure offline, pace the calls, keep provenance and consultation numbers.
Updated 2026-10-28
- XRechnung erstellen per API
XRechnung 3.0 per API erzeugen: Rechnungsdaten als JSON senden, UBL oder CII zurück, gegen Schema, EN 16931 und XRechnung-Regeln geprüft, ohne Speicherung.
Updated 2026-10-28
- ZUGFeRD erstellen per API (Factur-X, PDF/A-3)
ZUGFeRD 2.x / Factur-X im Profil EN 16931 per API: PDF/A-3 mit eingebetteter factur-x.xml, von veraPDF und Mustang geprüft, lesbare Seite in vier Sprachen.
Updated 2026-10-28
- Peppol BIS Billing 3.0 validator
Validate a Peppol BIS Billing 3.0 invoice against the UBL 2.1 schema, the CEN EN 16931 rules and the Peppol 3.0.21 rules, Belgian 0208 checks included, by API.
Updated 2026-10-28
- Kleinunternehmer und E-Rechnung
Kleinunternehmer nach § 19 UStG und die E-Rechnung: was gilt, wie die Steuerbefreiung in XRechnung und ZUGFeRD steht (Kategorie E) und wie die API sie schreibt.
Updated 2026-10-28
- EN 16931 rules explained
The EN 16931 business rules decoded: rule families, the XRechnung and Peppol layers, severities and custom levels, the ten most frequent failures and their fix.
Updated 2026-10-28
- XRechnung prüfen und validieren: was geprüft wird, woran es scheitert
Eine XRechnung prüfen heißt: XML-Schema, EN-16931- und XRechnung-Regeln wie im KoSIT-Validator. Was geprüft wird, die häufigsten Fehler, kostenlose Prüfung.
Updated 2026-10-28
- E-Rechnung API: XRechnung, ZUGFeRD und Peppol BIS per REST erzeugen, prüfen, lesen
Eine E-Rechnung-API erzeugt, prüft und liest XRechnung, ZUGFeRD und Peppol BIS per REST: die drei Aufrufe, Kosten je Rechnung, Fristen nach § 14 UStG, Grenzen.
Updated 2026-10-28
- EU VAT validation APIs compared (2026): price per 1,000, free tier, consultation numbers, outages, residency
Eight EU VAT validation APIs compared on price per 1,000, free tier, consultation numbers, VIES outages and data residency, read 2026-10-28.
Updated 2026-10-28
- Vatstack alternative: EU VAT APIs compared on price and VIES outages
Vatstack, TrustComponent, Apify wrappers and Veriport compared on price per 1,000 VAT checks, free tier, cache when VIES is down, consultation numbers and bulk.
Updated 2026-10-28
- vatlayer (apilayer) alternative: Veriport and vatlayer (apilayer) compared on price, evidence and VIES outages
vatlayer Basic is $9.99 a month for 1,000 requests. Veriport answers the same VIES check from a free tier, with a dated cache when a state is down.
Updated 2026-10-28
- Abstract API alternative: Veriport and Abstract API compared on price, evidence and VIES outages
Abstract’s VAT API is $99 a month on the Standard plan. Veriport validates on VIES from a free tier, dated cache when a state is down, consultation numbers.
Updated 2026-10-28
- VATSense alternative: Veriport and VATSense compared on price, evidence and VIES outages
VATSense starts at $6.99 a month for 500 requests and adds UK and EORI numbers. Veriport is prepaid with a dated cache when VIES is down; compared here.
Updated 2026-10-28
- vatcheckapi alternative: Veriport and vatcheckapi compared on price, evidence and VIES outages
vatcheckapi is $9.99 a month for 2,000 validations on servers in Germany. Veriport is prepaid, keeps a dated cache when a state is down and runs in Paris.
Updated 2026-10-28
- VIES API (viesapi.eu) alternative: Veriport and VIES API (viesapi.eu) compared on price, evidence and VIES outages
viesapi.eu starts at €8 a month for 1,000 requests, billed annually. Veriport is a REST API with a free tier, prepaid packs and a dated cache when VIES is down.
Updated 2026-10-28
- Stripe Tax alternative: Veriport and Stripe Tax compared on price, evidence and VIES outages
Stripe validates a customer’s EU VAT number on VIES inside Billing and Tax. For the check outside Stripe, with a consultation number and a dated cache.
Updated 2026-10-28
- TaxJar alternative for rate lookups: when all you need is the rate
TaxJar Starter is $39 a month in 2026. If you only need rates, Veriport answers from public state data with the coverage of each ZIP stated, from a free tier.
Updated 2026-10-24