If you search the Shopify App Store for "invoice", you get pages of capable-looking apps, many with excellent reviews. They are not interchangeable: document design, workflow breadth, VAT controls, and structured e-invoicing are different buying criteria. This guide gives you the questions that separate them and a sourced view of where the established apps and Facturely each fit.

A disclosure up front: we build Facturely, one of the apps discussed. To keep this useful rather than promotional, the core of this page is a vendor-neutral checklist you can run against any app's listing, docs, and support team — including ours. App features change; verify against current listings before deciding.

The seven questions that separate invoice apps

1. Does it use a dedicated, controlled invoice number series?

EU VAT rules require a sequential number that uniquely identifies each invoice. Shopify order numbers serve a different operational purpose and can include cancelled or test orders. A dedicated series assigned when the invoice is issued makes reconciliation and gap explanations much simpler. Ask whether the app maintains its own transactional counter, supports a clear prefix or yearly series, and prevents duplicates.

2. Are issued invoices immutable?

Some apps re-render invoices from current product data — so a price change or product rename silently alters documents issued months ago. That breaks German GoBD requirements and equivalent immutability rules elsewhere. Ask: once issued, is the document frozen? Test it: issue an invoice, change the product's price, re-download the invoice.

3. Are refunds handled with sequential credit notes?

A refund must produce a credit note — its own numbered document referencing the original invoice, with negative amounts per VAT rate — not an edited or deleted invoice. Ask: does the app create credit notes automatically on Shopify refunds, in their own number series?

4. Does it validate VAT IDs through VIES — and store the proof?

For B2B reverse charge, a format check alone does not establish that a VAT number was valid for intra-EU transactions. Look for a real VIES lookup with the response evidence stored. Ask when validation occurs, what evidence is retained, and whether you can retrieve it later.

5. Does it apply the correct reverse-charge treatment and wording?

Valid EU VAT ID → no VAT charged → the exact prescribed mention ("Reverse charge" / "Steuerschuldnerschaft des Leistungsempfängers" / "Autoliquidation"…), with the right legal basis for services (Art. 196) versus goods (Art. 138). Ask to see a sample B2B cross-border invoice.

6. Is it ready for structured e-invoicing?

Germany's issuing mandate arrives 2027–2028; France's platform-based system starts September 2026; ViDA extends structured e-invoicing EU-wide to intra-EU B2B in 2030. PDF-only output has a shelf life. Ask: what is the roadmap for EN 16931 formats — ZUGFeRD/Factur-X, XRechnung?

7. What does pricing scale on?

Some apps price on total store orders, so you pay for B2C volume even if only a fraction of orders need compliant invoices. Others price on invoices generated. Check which model fits your mix.

What the current product pages show

Sufio is a mature, design-led option with branded documents and broad language support. Its current Shopify App Store listing describes sequential numbering and EU VAT-number validation; Sufio also documents automatic credit notes and publishes updates on ZUGFeRD/Factur-X and Peppol e-invoicing in Belgium. Check the exact country, workflow, and plan that apply to your store.

Order Printer Pro (FORSBERG+two) is positioned as a broad document workflow for invoices, packing slips, returns forms, and receipts. Its current Shopify App Store listing includes sequential numbering, credit notes, and an in-app e-invoicing and Peppol add-on. If it is on your shortlist, ask specifically how it handles VIES consultation evidence, issue-time document snapshots, and country coverage for that structured e-invoicing add-on.

Both are established products with real track records. The right choice depends on which capabilities you need and how each vendor implements them today. Use the checklist above against current documentation, request a sample for your exact transaction, and get any critical answer from the vendor in writing.

Where Facturely fits

Facturely was built compliance-first, for merchants whose invoicing risk is European:

• a dedicated invoice number series with transactional allocation, configurable prefix, and yearly reset, assigned at issuance rather than derived from order numbers;
• immutable documents by construction — issued invoices are frozen snapshots; corrections only ever happen through sequential credit notes created automatically on refunds;
• VIES validation with stored consultation proof and correct per-language reverse-charge wording on B2B invoices;
• automatic delivery — invoice emailed to the customer when the order is paid, credit note on refund, no manual step;
• pricing on invoices generated, not your total order count.

That gives Facturely a focused role in the category: automate the VAT-invoice controls a Shopify merchant uses every day, while treating structured e-invoicing as the next layer of the product.

The bottom line

Choose with the checklist, not the screenshot gallery. Ask every candidate app — ours included — the seven questions above, keep the answers, and test a paid order plus refund before committing your workflow.

Start with Facturely's automated VAT-invoice foundation today — sequential numbering, frozen issue-time records, VIES checks, and refund credit notes — and follow our structured e-invoicing roadmap for Germany and France.

This article reflects our understanding of the category as of August 2026 and is general information, not tax advice. Verify current app capabilities against their listings, and consult a qualified tax advisor for your specific situation.