What's different about onboarding and paying an international vendor?

Generally yes - the verification tools you lean on domestically are weaker abroad. Phone call-backs are harder across time zones and languages, banking systems differ, and sanctions exposure is higher. Compensate with stronger documentation requirements, careful sanctions screening, and verification methods that don't depend on a same-day phone call. The added friction is proportionate to the added risk.

Beyond account holder name: IBAN (Europe and many other regions), SWIFT/BIC for the receiving bank, and country-specific clearing details - UK sort codes, Canadian transit/institution numbers, and other local formats. The exact set varies by country and payment rail; collect the full corridor-specific set at onboarding so a payment doesn't fail mid-run for a missing field.

Set the vendor's default payment currency on the record for consistency, but allow per-invoice override where a vendor legitimately bills in multiple currencies. Confirm the beneficiary account's currency matches the payment currency - a mismatch between the payment and the receiving account is a common cause of failed international payments.

Usually format mismatches: an IBAN with wrong length or check digits for the country, a SWIFT/BIC that doesn't resolve, or local clearing codes entered in the wrong field. Validate against the specific country's format, and confirm the SWIFT and the country agree - a SWIFT pointing to a different country than the vendor claims is both an error and a potential fraud signal.

It depends on the jurisdiction and the nature of the supply - some cross-border services are zero-rated or reverse-charged, others carry foreign VAT/GST. Generally you can't reclaim foreign VAT the way a domestic registrant would; treat it as part of the cost unless a recovery mechanism applies. For material amounts, get tax advice on the specific corridor.

It's the foreign equivalent of a tax identifier, used for their VAT/GST compliance and sometimes required on invoices. Validate it where it matters for your own compliance (e.g., EU VAT numbers can be checked via VIES) - but it serves a different purpose than a US TIN and doesn't feed your 1099/1042-S logic, which keys off the W-8.

Lean on methods that don't require a live same-day call: verification through the vendor's authenticated portal account, confirmation against the executed contract, a verified bank document, email confirmation to a known-good address plus a scheduled call, and careful banking-format and SWIFT/country consistency checks. Layer several weaker signals when the single strong signal (a trusted phone contact) isn't available.

Jurisdiction-specific, but commonly: the vendor's legal name and address, their VAT/tax registration number, invoice date and number, a description of goods/services, amounts, and the VAT treatment (rate, or a reverse-charge/zero-rate notation). If you need the invoice to support a tax position, confirm it carries the elements that jurisdiction requires.

Apply enhanced diligence by corridor: rigorous sanctions screening, stronger identity and banking verification, and awareness of any restrictions on payments to certain countries. Maintain a list of higher-risk corridors with the extra steps each requires, and treat banking changes from those vendors with the highest scrutiny.

Stampli's customizable onboarding forms let teams route international vendors through a different intake that captures the tax documentation, currency preferences, and international banking fields foreign payees require - with currency preferences and banking details captured before payments are initiated. Those details live on the vendor record with full history, and international banking details can be checked for country and SWIFT/IBAN consistency as part of the payment-integrity controls, surfacing mismatches before money moves.