Run Kassa inside your own platform: open managed accounts, issue deposit addresses, take payments through a hosted checkout, and route withdrawals to your treasury wallet — all over a simple, key-authenticated REST API.
API access is issued to your main Kassa account from the dashboard. It is designed for businesses that hold custody with us and automate on top of it.
Create your key at kassa.app → Developer API. It is shown once; we store only a hash. Keys can be suspended or revoked at any time from the dashboard.
Every call carries your key in the X-API-Key header over HTTPS. Base URL: https://api.kassa.app
The key can send money to exactly one place: the payout address you configure. Changing it requires your account password on top of the key, so a leaked key alone can only ever pay you.
Charge a customer without building any crypto UI. Create a session, send the customer to the URL, and poll the status (or let the page redirect to your success_url). The page shows the amount, a QR code, a live countdown and confirms automatically when the payment lands.
Sessions run 5–120 minutes. Partial payments are shown to the payer and stay credited to you; the session completes when the full amount has arrived.
| 400 | Invalid input, insufficient balance, or a platform limit — the message says which. |
| 401 | Missing, unknown or revoked key; wrong account password. |
| 403 | Key suspended, yearly fee lapsed, or the action is not allowed for this account. |
| 404 | Resource does not exist or belongs to someone else. |
| 409 | Conflict — e.g. the email is already registered. |
| 429 | Rate limited — back off and retry. |
Errors are JSON: {"detail": "human-readable reason"}
Sign in, fund your account, and create your key under Developer API. Questions → support@kassa.app