> ## Documentation Index
> Fetch the complete documentation index at: https://docs.grail.oro.finance/llms.txt
> Use this file to discover all available pages before exploring further.

# API Support

GRAIL will provide comprehensive APIs for Distribution Partners to integrate with their existing systems, supporting both Custodial and Self-Custody models:

### User Management API

* Create users with KYC-hashed identifiers.
* For **Self-Custody**: Link user's KYC hash with their public Web3 wallet address, potentially including a wallet ownership verification step.
* Check user status, KYC linkage, and (for Custodial model) gold balances managed by the program.

### Transaction API

* **Custodial Model**:
  * Purchase gold for individual users (locked to their User PDA).
  * Purchase gold for the Distribution Partner's reserves.
  * Withdraw unused USDC and unlocked gold from the central vault (Partner's Withdrawal Authority).
* **Self-Custody Model**:
  * Facilitate user-initiated gold purchases: Provide transaction details for user signing (USDC from user wallet, gold to user wallet), manage KYC checks.
  * Purchase gold for the Distribution Partner's reserves.
  * Facilitate withdrawal of unused USDC and unlocked gold from their own reserves.
* The API will clearly distinguish endpoints or parameters for Custodial versus Self-Custody operations where necessary.

### Reporting & Balances API

* Current gold prices and estimates.
* **Custodial Model**: Distribution Partner's central vault contents, User PDA gold balances.
* **Self-Custody Model**: Distribution Partner's operational vault contents. User gold balances are on their respective wallets, but the API can report on KYC-verified users and their transaction history through the platform.