E-invoicing rules — format and deadline checks
Mandatory e-invoicing is arriving country by country, each with its own format, date and exemption. These checks read the invoice or the setting you already have and show what fails the rule.
15 tools
E-Invoice Mandate Lint - EU 2026
VS Code extension
Lints UBL and CII invoice XML against EN 16931 and the national e-invoicing mandates that are live in 2026
France E-Invoice Reception Lint
VS Code extension
12 checks for the French mandatory mentions a PDP rejects, on Factur-X, UBL and CII invoices
KSeF FA(3) Invoice Lint
VS Code extension
Finds the lines KSeF will reject in a Polish structured invoice XML, before you send it
EN 16931 e-Invoice Lint
VS Code extension
Checks an invoice payload or field mapping against EN 16931 and the national CIUS of the country it detects — 29 rules, in your editor.
Invoice Source Code for Arduino: VAT Receipt Printer with Sequential Invoice Numbers
6 Arduino Mega sketches for a 58 mm thermal printer: VAT in whole pence, simplified receipts up to £250 (UK) or 100 euros (EU), numbered full invoices above that.
Construction Budget Spreadsheet UK 2026: CIS Deduction, Retention and Reverse Charge VAT
Spreadsheet calculator
CIS takes 20% of the labour part of every payment (30% if you are not CIS-registered), and since 1 March 2021 the domestic reverse charge sends the 20% VAT on your…
PHP PDF Library for EU VAT Invoices (Art. 226, 2026)
Pure-PHP invoice PDFs that refuse to render when an Art. 226 field is missing: 15 checks, reverse-charge wording in 6 languages, €1,900 VAT deduction caught in the…
Dashboard UI Kit for EU SaaS Billing — VAT ID, Reverse Charge & OSS States (Figma + Sketch)
Figma kit
8 billing components, 27 variants with the invoice wording EU VAT law asks for.
MyInvois Field Check — Malaysia e-Invoice (UBL 2.1)
VS Code extension
Finds the fields IRBM rejects in a MyInvois JSON payload, on the line, before you submit.
Belgium E-Invoice Fine & 120% Check 2026
Browser extension · Chrome, Edge, Firefox
What one PDF-only B2B invoice costs a Belgian seller now that the tolerance period is over — and what the 120% deduction gives back
KSeF 10k Exemption Watch - the invoice that ends it
Browser extension · Chrome, Edge, Firefox
Poland, 2026: find the exact invoice that kills your PLN 10,000/month KSeF exemption, and the date it stops mattering.
German E-Invoice Clock 2027 - which Sec. 14 UStG date binds your German entity
Browser extension · Chrome, Edge, Firefox
2027-01-01 or 2028-01-01, the go-live buffer you have left, and the 8-year archive year
France E-Invoicing 2026: Penalty & Deadline Check
Browser extension · Chrome, Edge, Firefox
Your own issuance date, your reception status, and what running late actually costs — €15 per invoice and €500 per missed e-report, each capped at €15,000 a year.
Reverse Charge VAT Invoice Checker 2026
Browser extension · Chrome, Edge, Firefox
Returns eight answers on any cross-border invoice: whether it is reverse charge, the exact wording the law demands, and the VAT your own tax office would assess if the…
Billable Tab Timer for Hourly Freelancers & Consultants — Firefox extension that turns tabs into client hours and invoice-ready CSV (0.1-hour or 15-minute rounding, works offline)
Your rate is the multiplier: every block of unlogged browser time is at least one billing increment.
Questions
Do my files leave my computer?
No. The extensions and command-line checks run on your machine and your files are not uploaded. The browser calculators run in the page.
What does it cost?
Every tool is free for the file or case in front of you. The paid part is a one-time licence key; each tool page shows its price and what the key adds. A team key ($149 once) opens every ReadyStack linter for five seats and CI.
More collections
US payroll, tax and filing deadlines — 2026 checksUK tax, payroll and HMRC rules — 2026/27 checksEU rules with a 2026 date — deadline and fine checksPrivacy and data protection — rule checksAccessibility — WCAG and EAA checksSecurity and supply chain — linters for the rules that bind softwareDeveloper deadlines — deprecations, removed APIs and build breaksSelling online — pricing, fee, email and consumer-law rulesAI rules and agent configuration — lintersSubmission gates — pass the store or registry review the first timeHealth and medical software — regulatory checksExam flashcards — licensing and certificationTemplates and design assetsDeutschland 2026 – Fristen, Lohn, Steuer und Pflichten All tools