European SaaS founders comparing payment providers usually start with Stripe because it's the default everywhere, then discover that Mollie and Adyen exist specifically because Stripe's one-size-fits-all approach doesn't always fit the European market. The right choice depends on your customer base, your transaction volume, and whether local payment methods like iDEAL and Bancontact actually move your conversion rate.
The three providers in one sentence each
Stripe is the global default: broad country coverage, the strongest developer experience, and the most flexible billing infrastructure, at a standard rate but with less depth on European local payment methods unless you configure them explicitly. Adyen is the enterprise-grade processor built for high-volume, omnichannel businesses, offering lower blended rates at scale through interchange-plus pricing but with meaningfully more complex integration. Mollie is what a payments provider looks like when it's built exclusively for Europe: fast onboarding, transparent per-method pricing, and the deepest native support for iDEAL, Bancontact, SOFORT, and dozens of other regional methods.
Where the fee math actually lands
At moderate volume — illustratively, around €500K annual revenue — Stripe's convenience costs roughly 0.3% to 0.8% more than Adyen once currency conversion spreads and chargeback handling are factored in. Adyen's blended rate at that scale runs approximately 0.6% to 1.1% plus €0.10 to €0.15 per transaction, but the integration takes six to eight weeks against Stripe's much faster setup. Mollie prices per payment method rather than a single blended rate: iDEAL runs a flat €0.32 regardless of transaction size, Bancontact €0.39, and card payments 1.80% to 2.90% plus €0.25. For a business processing mostly iDEAL or Bancontact transactions, that flat-fee structure beats percentage-based card pricing significantly on larger transaction values.
Currency conversion is a cost most founders underweight. Stripe's spread runs around 3.25%, Adyen's 2.5% to 3%, and Mollie's around 3%. At €100,000 in cross-border volume, the gap between Stripe and Adyen alone works out to roughly €750 a year — a number that compounds fast for any SaaS company selling to UK or US customers from a European base.
VAT compliance matters more than the fees
None of the three processors is a merchant of record. Stripe, Adyen, and Mollie all leave you as the legal seller responsible for VAT registration, collection, and filing across every EU country where you have customers. Stripe Tax helps calculate what you owe, but the registration and filing burden is still yours. If your priority is offloading that burden entirely, none of these three solve it — that's a job for a merchant of record like Paddle or Lemon Squeezy, and it's worth deciding early which problem you're actually trying to solve.
When each provider actually wins
Mollie is the right call if the bulk of your customers are in the Netherlands, Belgium, Germany, or nearby markets and local payment method conversion matters more than global reach. Its limitation is geographic: it supports 20-plus EU countries and doesn't extend to the US, Asia, or Latin America. Adyen wins at genuine scale, particularly for omnichannel businesses running both online and in-person payments, but the integration complexity isn't worth it below roughly €500K to €1M in annual volume. Stripe remains the sensible default for SaaS founders who need global reach and the strongest developer tooling, provided you explicitly enable European local payment methods rather than relying on defaults.
What I'd tell a founder choosing today
Don't default to Stripe without configuring EU payment methods. iDEAL, Bancontact, and SEPA aren't enabled automatically, and skipping them costs conversion in markets where they're the preferred checkout option.
Model your actual customer geography before choosing. If 80% of your revenue is Dutch or Belgian customers, Mollie's flat per-method pricing likely beats Stripe's percentage-based card fees on anything above a small transaction size.
Treat VAT compliance as a separate decision from payment processing. All three processors leave VAT registration and filing on your plate — decide early whether you want a processor or a merchant of record.
Reassess at each revenue milestone, not just at launch. The provider that makes sense at €50K ARR is rarely the one that makes sense at €500K, particularly once Adyen's interchange-plus pricing starts beating flat-rate processors.
Price in currency conversion, not just per-transaction fees. For any SaaS selling outside the eurozone, the FX spread difference between providers compounds into real money faster than the headline transaction fee does.
Mollie, Adyen, and Stripe solve genuinely different problems for European SaaS founders, and the right pick depends on customer geography and volume more than any single fee line. None of them solve VAT compliance, and pretending a payment processor will is the mistake I see founders make most often right before their first unexpected tax notice.