Crypto Lending Quickstart

The four endpoints below cover the full Flex lifecycle — fetch plans, invest, check status, withdraw — operating against Main balance. Access requires B2B partner permissions plus a key with the Trade permission.

Prerequisites

A WhiteBIT account with completed KYC (register)
An API key with Trade permission (create key)
B2B partner access to the lending endpoints (institutional services form)
Funds in Main balance (the lending API operates on Main balance, not Trade balance)
HMAC-SHA512 signing configured (authentication guide)
curl and jq installed (for command-line examples)

Both Flex and Fixed plan endpoints require B2B partner permissions. Request access via the institutional services form. See the overview for details.

Fetch available Flex plans

Retrieve the list of available Flex plans to find a plan ID for investment.

cURL
Python

curl -X POST https://whitebit.com/api/v4/main-account/smart-flex/plans \
  -H "Content-Type: application/json" \
  -H "X-TXC-APIKEY: YOUR_API_KEY" \
  -H "X-TXC-PAYLOAD: YOUR_PAYLOAD" \
  -H "X-TXC-SIGNATURE: YOUR_SIGNATURE" \
  -d '{"request": "/api/v4/main-account/smart-flex/plans", "nonce": 1709340000000}'

import requests, json, hmac, hashlib, base64, time

API_KEY = "YOUR_API_KEY"
API_SECRET = "YOUR_SECRET"
BASE_URL = "https://whitebit.com"

def make_request(endpoint, body):
    nonce = int(time.time() * 1000)
    body["request"] = endpoint
    body["nonce"] = nonce
    data_json = json.dumps(body)
    payload = base64.b64encode(data_json.encode())
    signature = hmac.new(
        API_SECRET.encode(), payload, hashlib.sha512
    ).hexdigest()
    headers = {
        "Content-Type": "application/json",
        "X-TXC-APIKEY": API_KEY,
        "X-TXC-PAYLOAD": payload.decode(),
        "X-TXC-SIGNATURE": signature,
    }
    return requests.post(f"{BASE_URL}{endpoint}", headers=headers, data=data_json)

# Fetch available Flex plans
response = make_request("/api/v4/main-account/smart-flex/plans", {})
plans = response.json()
print(json.dumps(plans, indent=2))

For Go and PHP examples, see SDKs.Expected response:

[
  {
    "id": "8f2e9d3c-1a4b-4c2d-9e5f-6a7b8c9d0e1f",
    "ticker": "USDT",
    "minInvestment": "10.0",
    "maxInvestment": "100000.0",
    "maxRate": "0.15"
  },
  "..."
]

Save the id value from a plan to use in the next step.

Create a Flex investment

Invest into the selected Flex plan using the plan ID from Step 1. Sign the request as in Step 1 (make_request builds the payload and signature); for language clients, see SDKs.Endpoint: POST /api/v4/main-account/smart-flex/investments/invest

Field	Type	Required	Description
`plan`	string (UUID)	Yes	Plan ID from Step 1
`amount`	string	Yes	Amount to invest
`withReinvest`	boolean	No	Enables auto-reinvestment

Expected response:

{
  "data": {
    "transaction_id": "tx_9f3e0d4c-2b5c-4d3e-8f6g-7a8b9c0d1e2f"
  }
}

Check investment status

Verify the investment was created and check its status. Sign the request as in Step 1.Endpoint: POST /api/v4/main-account/smart-flex/investments (no additional fields)Expected response:

{
  "data": [
    {
      "id": "inv_7e2d9c3b-1a4b-4c2d-9e5f-6a7b8c9d0e1f",
      "planId": "8f2e9d3c-1a4b-4c2d-9e5f-6a7b8c9d0e1f",
      "currency": "USDT",
      "invested": "100.00",
      "withAutoReinvest": true,
      "status": 1,
      "..."
    }
  ],
  "..."
}

Withdraw from investment

Withdraw funds from the Flex investment back to Main balance. Sign the request as in Step 1.Endpoint: POST /api/v4/main-account/smart-flex/investments/withdraw

Field	Type	Required	Description
`plan`	string (UUID)	Yes	The plan to withdraw from
`amount`	string	Yes	Amount to withdraw; partial withdrawals supported (use the full invested amount to withdraw everything)

Expected response:

{
  "data": {
    "transaction_id": "tx_9f3e0d4c-2b5c-4d3e-8f6g-7a8b9c0d1e2f"
  }
}

After completing Step 4, the withdrawn amount returns to the Main balance. Verify by checking the Main balance endpoint.

What’s Next

Crypto Lending Overview

Fixed vs Flex plan mechanics, B2B partner permissions for lending endpoints, ~90 supported assets, and auto-invest behavior.

API Reference

Full endpoint documentation for all 13 lending endpoints.

For Go and PHP examples, see SDKs.

​Prerequisites

​What’s Next

Crypto Lending Overview

API Reference

Prerequisites

What’s Next