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Documentation Index

Fetch the complete documentation index at: https://docs.quantumapi.io/llms.txt

Use this file to discover all available pages before exploring further.

The Custody API uses a two-level hierarchy to organize blockchain addresses: vault accounts contain wallets, and wallets hold assets on the Quantum Chain network.

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Vault accounts

A vault account is a logical container that groups related wallets. Common patterns:
  • By purpose: “Treasury”, “Operations”, “Cold Storage”
  • By department: “Engineering”, “Finance”, “Trading”
  • By client: one vault per end customer in a platform model

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Create a vault account

curl -X POST "$BASE_URL/vault/accounts" \
  -H "Authorization: Bearer $CUSTODY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"name": "Treasury", "tenant_id": "tnt_abc123"}'

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List vault accounts

curl "$BASE_URL/vault/accounts" \
  -H "Authorization: Bearer $CUSTODY_API_KEY"

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Wallets

A wallet represents a single Quantum Chain address within a vault account. Each wallet has:
  • Address: the Quantum Chain hex address
  • Public key: the post-quantum public key associated with the address
  • Name: an optional human-readable label

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Non-custodial registration

Since the Custody API is non-custodial, you register existing wallets rather than having the API generate keys. You provide the address, post-quantum public key, and an ownership proof from your external key management system.

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Ownership proof

To prevent registering wallets you do not control, every registration request must include a signature over a deterministic challenge:
  1. Compute the challenge: Keccak256("qustody:register:" + lowercase_address)
  2. Sign the 32-byte challenge with your post-quantum private key
  3. Include the hex-encoded signature in the signature field
The API verifies that the public key derives to the given address and that the signature is valid. 
curl -X POST "$BASE_URL/vault/accounts/{vaultAccountId}/wallets" \
  -H "Authorization: Bearer $CUSTODY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "address": "0x1234...abcd",
    "publicKey": "<hex-encoded-public-key>",
    "signature": "<hex-encoded-ownership-signature>",
    "label": "Hot Wallet"
  }'

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Query wallet balance

curl "$BASE_URL/wallets/{walletId}/balance" \
  -H "Authorization: Bearer $CUSTODY_API_KEY"

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Assets

Assets represent token types held in wallets. The Quantum Chain native token is Quantum (symbol QUANTUM); it is referenced in the API by asset_id: "QUANTUM".

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Vault-level asset summary

Get aggregated balances across all wallets in a vault: 
curl "$BASE_URL/vault/accounts/{vaultAccountId}/assets" \
  -H "Authorization: Bearer $CUSTODY_API_KEY"

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Global asset catalog

List all supported assets: 
curl "$BASE_URL/assets" \
  -H "Authorization: Bearer $CUSTODY_API_KEY"

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Hierarchy diagram

Each wallet belongs to exactly one vault account. A vault account belongs to exactly one tenant. Cross-tenant access is not permitted.