Sadly pretty normal for European companies. The penalties they face for signing up a bad customer are so much harsher they won't risk letting just anyone sign up without actual KYC not just checkbox KYC. This is the same reason Hetzner turns away 50% of its customers.
I used to work at Stripe and they subject to the same penalties as Ayden. There is a misconception that Stripe is an American only company, they have dual HQ model in Ireland and San Francisco. Since they are an Irish founded company and they have an EU entity “Stripe Technology Europe”. They can be kicked out of entire countries and regions if they didn’t have an extensive KYC systems and be fined just the same.
Since Stripe operates by working with a BIN (banks that sponsor them within each country) generally like all payment providers. While the decline rates for new customers are not public, they are very high, especially for industries that aren’t allowed like Adult Content, Weapons, and Gambling [1]. Also revocation of existing accounts can happen often if KYC systems flag anything, like Stripe Identity, Connect, and Radar.
Mollie (also Dutch) existed even before Adyen (and way before Stripe). They have no problem dealing with small customers, and have always offered a trivially easy to use API.
Love for Mollie - and literally had this exact theme last year at work. Stripe implemented, then customer A couldn't use it due to US base, so went to Adyen, built integration, rejected as less than $5 million as first responder said, then went to Mollie.
Only gripe is no embeddable checkout but its not a huge deal, and they have superior test platform than even Stripe. The test cards are right there in slide in panel, and you have option to select paid/cancel/fail etc to test different outcomes.
Mollie B.V. is licensed and registered as an electronic money institution with the Dutch Central Bank (relationship number: F0038). Mollie UK Ltd is licensed and registered with the Financial Conduct Authority as a payment institution in the UK (FRN: 977968).
Stripe has a Get started button. You click it, fill out a form, get your site approved in maybe a day, and start making money.
Adyen has a Talk to our team button. You close the tab and never think about it again until you’re making serious money.
---
Edit: that is, of course, by design. Adyen doesn’t want small businesses. From the sibling comment:
> only able to support businesses currently transacting more than €5M per year