I have just had a French customer write to say that he has just refused a parcel, after being asked for 13€ from postman and that he will not be ordering from us again due to this situation! There was notification on the La Poste tracking to say 2€ customs fees were due, which I was also surprised by, but obviously not a lot of money, but an extra 13€ for a t-shirt when you have already paid tax, is crazy! That is what signing up to this system was supposed to avoid! So frustrating…we have our IOSS number going on our Click & Drop CN22 labels on the outside of the packaging. IOSS is set-up in Shopify and charging correct local tax amounts. I can’t figure out what else we can do? 
Topic summary
Feature request to allow UK merchants to integrate Taxamo Assure at checkout to collect EU VAT via IOSS post‑Brexit. Goal: charge VAT at checkout and remit via an intermediary to avoid delivery‑time charges and returns.
Shopify status and guidance:
- Checkout API (needed for Taxamo) is limited to Shopify Plus; no timeline to change. No built‑in IOSS intermediary integration. Third parties must build apps.
- “Registration‑based taxes” can be enabled to calculate local EU VAT and accept an IOSS ID (IOSS = for non‑EU sellers; OSS = for EU sellers).
Workarounds and apps:
- Taxamo: no Shopify plugin (focused on Magento). Custom API possible but complex; one merchant reports non‑Plus implementation via developer.
- Crossborderit (CBIT): IOSS via Sweden; pricing evolved from ~€19.99/mo + €1/order to app ($24/mo) and later reports of €99/mo + 3% on VAT. Early CSV uploads were painful; the Shopify app later smoothed reporting. Mixed reports of customers still being charged VAT; many issues traced to Royal Mail Click & Drop and label/IOSS handling, later improved with IOSS‑marked services.
- Alternatives: Avalara (costly full service), VAT Digital, Zonos (adds % fee), Eurora, EAS EU Compliance (no monthly fee; €1.25/txn + €6 invoice fee >€30). Several merchants plan to switch to EAS.
Operational notes:
- IOSS applies to consignments ≤ €150 and covers VAT only (not duty). Keep IOSS ID off labels; ensure RM Click & Drop uses IOSS services. Germany also requires VerpackG/LUCID packaging registration.
Outcome: No native Shopify–Taxamo integration; viable paths are registration‑based taxes + third‑party IOSS services. Discussion remains open (e.g., EAS support for sole traders).