Proof of funds: what authorities actually accept
Why app-only bank statements get rejected, which accounts issue the stamped letter, and how proof-of-funds rules differ by country.
Proof of funds is the requirement that trips people up most often, because the format the authority accepts matters as much as the amount you hold. A perfectly adequate balance in the wrong kind of account is still a refused application.
Why digital bank statements get rejected
Many visa, tenancy and registration processes ask for a formal letter from your bank confirming your balance and that the account is held in your name, stamped or on headed paper. App-only banks frequently cannot produce this. What they offer instead is a PDF statement generated in the app, which some authorities accept and others refuse outright.
Wise and Revolut are both regulated institutions and their documentation is accepted by some embassies. It is not accepted by all of them, and the pattern is inconsistent enough that you should verify rather than assume. This is worth checking before you consolidate everything into a single digital account.
How the requirement differs by country
Germany
A blocked account (Sperrkonto) is the standard instrument for student visas.
Canada
The Guaranteed Investment Certificate is the proof-of-funds document for the Student Direct Stream.
UK and Australia
Statements are usually acceptable, but the holding period is scrutinised.
The practical approach
Keep a letter-capable account available even if you do your day-to-day banking elsewhere. A traditional bank account you barely use is a cheap insurance policy against a process that demands a stamped letter at short notice.
Before applying, ask the specific authority what format they accept, get the answer in writing where possible, and allow time for the document to be issued. Banks are not always quick at producing confirmation letters, and an appointment can add a week you have not budgeted for.