Custodian API Overview
The Xellar Custodian API lets you create and manage custodial wallets, accept crypto deposits via invoices, send withdrawals, track balances and transaction history, and receive real-time events through outbound webhooks.
What You Can Do
- Account & Wallets — Create custodial accounts and read their wallet addresses per network.
- Listen Wallet — Subscribe on-chain addresses so incoming deposits are detected.
- Invoice — Generate a payment request (a deposit address + amount) and track its status.
- Withdraw — Estimate fees and send funds to an external address.
- Assets & Transactions — Read balances per token and your ledger history.
- Webhook — Get notified on account creation, deposits, invoice lifecycle, and withdrawal status changes.
Base URL
All client endpoints are served under the /api/v1 prefix.
| Environment | Base URL |
|---|---|
| Development | https://custodian-api-dev.xellar.co/api/v1 |
| Production | Coming soon |
Authentication
Every client endpoint (except a couple of public listener endpoints) is protected by an ED25519 request signature. You authenticate using an App ID and a private key that you generate from the Xellar Dashboard.
See Authentication to get your key pair and learn how to sign requests.
Getting Started
- Get your App ID and private key from the dashboard.
- Create an account to provision custodial wallets.
- Create an invoice or subscribe an address to receive deposits.
- Configure a webhook to get real-time updates.
Need help? Email support@xellar.co or Telegram @xellarsupport.