Crypto Payment Infrastructure for Fintech: Build or Integrate

A fintech adding crypto capability faces a different decision from a merchant accepting crypto payments. The question is not whether to accept an asset, it is how much of the stack to own. The commercial equivalent of this arrangement is a licensed crypto payment processor, which is the easiest way to see it working.

What the stack contains

Wallet infrastructure and key management. Chain monitoring and transaction construction. Liquidity for conversion. Fiat settlement rails. Compliance: screening, travel rule, monitoring. And the authorisation to perform the activity at all.

Each layer can be built or sourced. The correct split depends on where your differentiation is and on what your licence permits.

The layer nobody should build first

Liquidity. Sourcing conversion at a competitive spread requires either inventory and market-making capability or relationships with those who have it. A fintech building this before it has volume is spending engineering effort on a problem that a partner solves at a price that is cheap relative to the cost of solving it badly.

Integrate liquidity. Revisit at the point where your volume makes the spread material.

The layer worth owning early

The user-facing experience and the ledger. This is where product differentiation lives and it is where a provider’s constraints will otherwise shape your product.

Own the record of what each user is owed. Source the movement of assets. This split keeps your product flexible and your provider replaceable.

The regulatory perimeter

The question that determines everything: does your fintech need its own authorisation, or can it operate under a partner’s. Property transactions surface the same constraint more sharply, and a provider serving funds and family offices exists for it.

If you hold crypto assets for users, that is custody and it requires the permission. If you exchange on their behalf, that is an exchange service. If you merely introduce users to a provider who does both, the perimeter may sit with the provider.

The distinction is not about the technical architecture, it is about who has the contractual relationship with the user and who controls the assets. Getting a clear legal view on this before building is considerably cheaper than getting one afterwards.

What to require from a partner

Authorisation covering every service they perform for you, verified on the register. If they custody for your users, they need the custody permission.

An API that supports your model. Sub-accounts or a ledger that maps to your users, if you need per-user attribution. Webhooks with signing and idempotency. Quote endpoints with honoured expiry.

Settlement in the currencies and countries your users need, which is usually the binding constraint.

Reporting that reconciles to your ledger without manual transformation, because you will be reconciling daily rather than monthly.

Clear allocation of compliance responsibility. Which party screens, which party reports, which party is responsible if something is missed. In writing.

The integration sequence that works

Start with a single corridor and a single asset. Prove the flow end to end including reconciliation and the failure cases. Then add assets, then corridors.

The failure mode is building a general abstraction over several providers before proving one works. The abstraction encodes assumptions from a provider you have not yet operated at volume.

The commercial question

Partner pricing is usually a spread on conversion plus a per-transaction or per-account fee. Negotiate on volume commitments once you have real numbers, not before.

What is worth negotiating harder than price: settlement frequency, the ability to add corridors without a new contract, and a notice period long enough to migrate if the relationship ends.

That last point is the one fintechs consistently under-negotiate. A ninety day notice period on a partner embedded in your payment flow is not enough time to replace them.

Providers offering crypto payment infrastructure for fintech companies under European authorisation generally expect these questions, and the quality of the answers is a reasonable proxy for how the relationship will run.