A predictable REST API, typed SDKs, an MCP server and a sandbox that behaves like production, for every product: accounts, collections, payouts and cards.
{{ r.d }}
With a sk_test_ key, magic values trigger specific outcomes. No real card is issued and no real funds move.
Every decline returns a stable code and a readable message, so your code or your agent knows whether to retry, ask for less or stop.
{{ errCode }}
{{ p.d }}
The sandbox is free and opens with test balances in several currencies.