Plenty of today's financial services look like a bank: there is an IBAN, a card, transfers, an app on your phone. Underneath, the structure can be different. That difference is not regulatory small print: it changes what happens to your money in the worst case.
A bank takes deposits, an e-money institution does not
A bank is authorised to take deposits from the public and lend that money out. That is its trade, and it is why it sits under heavy supervision. An electronic money or payment institution does not take deposits: it takes your money and turns it into electronic money, one for one. It lends it to nobody.
Where the money physically sits
Anyone issuing electronic money in the European Union must keep client funds separate from its own, in dedicated accounts at a bank or invested in safe, liquid assets. It is called safeguarding, and it serves one purpose: if the provider fails, that money does not fall into the pool for creditors, because it was never the provider's.
The €100,000 guarantee is not the same thing
The deposit guarantee scheme, which across the European Union covers up to €100,000 per depositor per bank, applies to bank deposits. It does not apply to electronic money. Safeguarding takes its place: two different mechanisms, with different procedures and different timescales. Anyone telling you they are the same is flattening something that, at the wrong moment, is not alike at all.
How to check, concretely
Every authorised provider is listed in a public register kept by its home authority, and the European Banking Authority's payment institutions register brings them together. The name of the authorised entity and its licence number belong on the service's own website, usually in the terms or the legal notices. If you cannot find them, that is already an answer.
What to look at before opening an account
Who the authorised entity is, and in which country. Where client funds are held. Which licence is in place (banking, electronic money, payment). How to file a complaint, and which authority to turn to if no answer comes. Four questions — and a serious service has the answers written down, not waiting behind a support queue.