OffBlocks
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        • πŸ¦Έβ€β™‚οΈCustomer States
        • 🏦Account States
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    • 🧬Smart Contracts
      • OffBlocksEscrow.sol
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      • 1️⃣API Credentials
      • 2️⃣Authentication
      • 3️⃣Request Preparation
      • 4️⃣Customer Creation
      • 5️⃣Customer Verification
      • 6️⃣Account Creation
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  • Use Cases
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    • 🏦Neo-banks and FinTechs
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Blockchain Updates

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Last updated 1 year ago

Our API includes various endpoints that involve on-chain activities and updates, such as ownership verification and smart contract deployment. In order to provide smooth experience and maximum level of security, we employ cryptographic challenges and signatures tailored to each supported blockchain.

Account Creation

To create a new account for the customer and set it up for fund transfers with OffBlocks, we need to deploy a smart-contract account to the respective blockchain. The customer remains the ultimate owner of this account, and to manage funds for off-chain transactions on the user's behalf, we need them to sign a session key issued in the form of a cryptographic challenge. Similar to other endpoints, the challenge returned by the endpoint is a Base64-encoded string.

To submit a signed challenge, please use the corresponding endpoint.

If, for any reason, the original challenge is lost or cannot be signed immediately, you can fetch it again using a dedicated endpoint. If we encounter an error during signature validation via /sign endpoint, a new challenge will be issued for you to retrieve.

βš™οΈ
πŸ“’

Retrieve account challenge

get

Retrieves challenge to sign account creation or deletion transaction on-chain. This operation invalidates any previously issued challenges for the account

Authorizations
Path parameters
accountIdstring Β· uuidRequired

Unique account ID

Header parameters
SignaturestringRequired

HTTP message signature

Signature-InputstringRequired

HTTP message signature input

Responses
200
Successful operation
application/json
400
Invalid request
401
Not authorised
404
Account not found
500
Internal error
get
GET /v1/accounts/{accountId}/challenge HTTP/1.1
Host: api.offblocks.xyz
Authorization: Bearer JWT
Signature: text
Signature-Input: text
Accept: */*
{
  "challenge": "LS0tLS1CRUdJTiBQVUJMSUMgS0VZLS0tLS0KTUZZd0VBWUhLb1pJemowQ0FRWUZLNEVFQUFvRFFnQUUzTEw1RldmVFgvL3BJaXNEL0xneFVIT2lxdlFTSUVWTgpGekloOTdLZXBlWk1iZVZsUGd1akZ4Yk5MN2x1ZVhRQnBpUWUzNmZLN0xSbXZNNHdEaWZFTkE9PQotLS0tLUVORCBQVUJMSUMgS0VZLS0tLS0="
}
  • Account Creation
  • POSTCreate new customer account
  • POSTSign previously issued account challenge
  • GETRetrieve account challenge

Create new customer account

post

Creates new account for the customer and generates a challenge to be signed in order to create a related blockchain account

Authorizations
Path parameters
customerIdstring Β· uuidRequired

Unique customer ID

Header parameters
SignaturestringRequired

HTTP message signature

Signature-InputstringRequired

HTTP message signature input

Idempotency-Keystring Β· uuidRequired

Idempotency key (UUID)

Content-DigeststringRequired

Content digest

Body
typestring Β· enumRequired

Type of the account

Possible values:
currenciesstring[]Required

Currencies of the account, at least one is required (ISO-4217)

Responses
201
Successful operation
application/json
Responseall of
and
400
Invalid request
401
Not authorised
404
Customer not found
500
Internal error
post
POST /v1/customers/{customerId}/accounts HTTP/1.1
Host: api.offblocks.xyz
Authorization: Bearer JWT
Signature: text
Signature-Input: text
Idempotency-Key: 123e4567-e89b-12d3-a456-426614174000
Content-Digest: text
Content-Type: application/json
Accept: */*
Content-Length: 45

{
  "type": "card_account",
  "currencies": [
    "text"
  ]
}
{
  "id": "123e4567-e89b-12d3-a456-426614174000",
  "customerId": "123e4567-e89b-12d3-a456-426614174000",
  "chainId": "eip155:1:0xab16a96D359eC26a11e2C2b3d8f8B8942d5Bfcdb",
  "status": "initiating",
  "type": "card_account",
  "currencies": [
    "text"
  ],
  "createdAt": "2025-05-09T07:30:55.809Z",
  "updatedAt": "2025-05-09T07:30:55.809Z",
  "challenge": "LS0tLS1CRUdJTiBQVUJMSUMgS0VZLS0tLS0KTUZZd0VBWUhLb1pJemowQ0FRWUZLNEVFQUFvRFFnQUUzTEw1RldmVFgvL3BJaXNEL0xneFVIT2lxdlFTSUVWTgpGekloOTdLZXBlWk1iZVZsUGd1akZ4Yk5MN2x1ZVhRQnBpUWUzNmZLN0xSbXZNNHdEaWZFTkE9PQotLS0tLUVORCBQVUJMSUMgS0VZLS0tLS0="
}

Sign previously issued account challenge

post

Signs previously issued challenge to sign account creation or deletion transaction on-chain

Authorizations
Path parameters
accountIdstring Β· uuidRequired

Unique account ID

Header parameters
SignaturestringRequired

HTTP message signature

Signature-InputstringRequired

HTTP message signature input

Idempotency-Keystring Β· uuidRequired

Idempotency key (UUID)

Content-DigeststringRequired

Content digest

Body

Cryptographic signature generated using owner's EOA private key according to chain-specific algorithm. Signature is used for signing on-chain transactions such as creating a new account, authorising a recurring payment or setting up spending limits

ownerIdstringRequired

Unique signer account ID in a form of a valid on-chain address

Example: eip155:1:0xab16a96D359eC26a11e2C2b3d8f8B8942d5Bfcdb
challengestring Β· byteRequired

Original base64 encoded challenge provided by this API for owner to sign

Example: LS0tLS1CRUdJTiBQVUJMSUMgS0VZLS0tLS0KTUZZd0VBWUhLb1pJemowQ0FRWUZLNEVFQUFvRFFnQUUzTEw1RldmVFgvL3BJaXNEL0xneFVIT2lxdlFTSUVWTgpGekloOTdLZXBlWk1iZVZsUGd1akZ4Yk5MN2x1ZVhRQnBpUWUzNmZLN0xSbXZNNHdEaWZFTkE9PQotLS0tLUVORCBQVUJMSUMgS0VZLS0tLS0=
signaturestring Β· byteRequired

Base64 encoded signature

Example: IfvwaW1eCqLvQaK0/7YjvK8HBGHWHPclHHQWH4L+w6Q3CFS8CjSzq0h8G8AhzTGMc0xRrik3TyvrDm8t1JtL9Bw=
Responses
204
Successful operation
400
Invalid request
401
Not authorised
404
Account not found
409
Challenge already signed
500
Internal error
post
POST /v1/accounts/{accountId}/challenge/sign HTTP/1.1
Host: api.offblocks.xyz
Authorization: Bearer JWT
Signature: text
Signature-Input: text
Idempotency-Key: 123e4567-e89b-12d3-a456-426614174000
Content-Digest: text
Content-Type: application/json
Accept: */*
Content-Length: 415

{
  "ownerId": "eip155:1:0xab16a96D359eC26a11e2C2b3d8f8B8942d5Bfcdb",
  "challenge": "LS0tLS1CRUdJTiBQVUJMSUMgS0VZLS0tLS0KTUZZd0VBWUhLb1pJemowQ0FRWUZLNEVFQUFvRFFnQUUzTEw1RldmVFgvL3BJaXNEL0xneFVIT2lxdlFTSUVWTgpGekloOTdLZXBlWk1iZVZsUGd1akZ4Yk5MN2x1ZVhRQnBpUWUzNmZLN0xSbXZNNHdEaWZFTkE9PQotLS0tLUVORCBQVUJMSUMgS0VZLS0tLS0=",
  "signature": "IfvwaW1eCqLvQaK0/7YjvK8HBGHWHPclHHQWH4L+w6Q3CFS8CjSzq0h8G8AhzTGMc0xRrik3TyvrDm8t1JtL9Bw="
}

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