The three roles get confused constantly. The shorthand: acquirers move money, PSPs move data, orchestrators decide what goes where. The implications for who you partner with and how you build are very different.
Who carries the risk
An acquirer is the regulated party that holds the merchant agreement with Visa, Mastercard and the other schemes. The acquirer takes the legal risk on the merchant, settles the funds, and is the entity that scheme rules and chargeback monetary flows go through. A typical platform works with multiple acquirers - different ones for different geographies, verticals or product types.
A PSP (payment service provider) is the technical layer that connects merchants to acquirers. PSPs handle integration, tokenisation, fraud screening, 3DS challenges, the developer experience. Some PSPs are also acquirers (Stripe, Adyen, Checkout.com); many are not. A PSP-only relationship gives you software, not regulatory cover.
Where the orchestrator sits
An orchestrator is the routing and decision layer above PSPs and acquirers. The orchestrator decides which PSP / acquirer a given transaction goes to first, what the cascade looks like on decline, what the fallback path is, what fee model applies. Orchestrators don't typically hold the merchant agreement themselves; they sit on top of the acquirers and PSPs you've chosen.
For a platform building payment infrastructure, the question is not 'which one should I use' but 'which combination'. Most serious platforms work with multiple acquirers, multiple PSPs, and an orchestration layer that ties them together. The orchestration layer is where most of the platform's competitive logic lives - routing rules, risk policy, fee structures, settlement logic - which is why the leading platforms build or buy this layer as a first-class concern.
