nuBlock Business API

Complete API reference for viewing enabled currencies, sending payments, and swapping cross-chain currencies.

Base URL
https://apipayments.nublock.xyz/api/business/v1
GET/enabledCurrencies?businessId=:businessId
Get Enabled Currencies
Retrieve the list of currencies enabled for a specific business account. Returns all supported currencies with their _id, name, symbol, decimal and price.

Parameters

The unique identifier for the account

Example Request

// Get enabled currencies for an account
const response = await fetch(
  'https://apipayments.nublock.xyz/api/business/v1/enabledCurrencies?businessId=:businessId',
  {
    method: 'GET',
    headers: { 
      'Content-Type': 'application/json'
    }
  }
);

const response = await response.json();
// Response: { _id, name, symbol, decimals, price }
console.log(response.data);
javascript
POST/
Send Payment
Initiate a new payment transfer to a recipient wallet address. Supports all enabled currencies.

Request Body

Example Request

// Send a payment
const response = await fetch(
  '',
  {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      amount: 1500,
      currencyId: '67ceda3edaadb',
      user_address: '0xabcd...ef12',
      recipientWallet: '0xabcd...ef12',
      apiKey: '68c8ed6be1d147a
    })
  }
);

const payment = await response.json();
console.log(payment.success, payment.data.to, payment.data.data, payment.data.value, payment.data.approve);
// When approve address is provided you need to approve it for token transfer
javascript
POST/
Swap
Initiate a new swap request for a wallet address. Supports enabled currencies.

Request Body

Example Request

// Swap
const response = await fetch(
  '',
  {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      amount: 1500,
      inputCurrencyId: '67ceda3edaadb',
      outputCurrencyId: '67ceda3edaadb',
      user_address: '0xabcd...ef12',
      apiKey: '68c8ed6be1d147a
    })
  }
);

const swap = await response.json();
console.log(swap.success, swap.data.to, swap.data.data, swap.data.value, swap.data.approve);
// When approve address is provided you need to approve it for token transfer
javascript
Widget/
Checkout Widget
Allows you to embed nuBlock payment gateway on your website store.

The Checkout Widget allows you to embed a secure checkout experience directly into your website using a simple JavaScript integration.

Prerequisites

  • Valid API Key
  • Basic knowledge of HTML & JavaScript
  • Access to edit your website's source code

Step 1: Include the Script

Add the widget script before the closing </body> tag.

<script src="https://auth.nublock.xyz/assets/js/pages/checkout-widget.js?businessId=:apiKey"></script>
javascript

Step 2: Add Button Container

Create a container where the checkout button will be rendered.

<div id="my_checkout" data-checkout-widget 
      data-amount="49.99"    
      data-currency="USD"    
      data-name="John Doe"    
      data-email="john@example.com" 
      data-phone="+1234567890"  
      data-account-id="API KEY"></div>
javascript

Step 3: Initiaze nuBlock Widget

window.nuBlockInitWidget()
javascript

Step 4: Read Transaction Status

window.addEventListener("message", handleMessage);

const handleMessage = (event: MessageEvent) => {
      // ✅ Only accept messages from popup
    if (!event.data || !event.data.status) return;

    if (event.data.status === "success") {        
      console.log("Success:", event.data);
    } else if (event.data.status === "failure") {
      alert("Payment Failed!");
      console.error("Failure:", event.data);
    }
  };
javascript
Demo Link : https://demo.checkout.nublock.xyz/
Source Code : https://gitlab.com/nuBlock/checkout_example_products_shoppingcart
Rate Limits & Fees
Understand API rate limiting policies, platform fees, and best practices for handling rate limit errors.

Overview

The nuBlock Business API implements rate limiting to ensure fair usage and maintain service stability. Rate limits are applied on a per-account basis.

Platform Fees

Transaction Fee15 bps

A platform fee of 15 basis points (0.15%) is applied to each transaction. This fee is automatically deducted from the transaction amount.

Example: For a $1,000 transaction, the platform fee would be $1.50

Rate Limit Tiers

StandardDefault tier
20 requests/min

Suitable for most integrations

Response Headers

Every API response includes headers with rate limit information:

HeaderDescription
X-RateLimit-LimitMaximum requests allowed per minute
X-RateLimit-RemainingNumber of requests remaining in current window
X-RateLimit-ResetUnix timestamp when the rate limit resets

Handling Rate Limit Errors

When you exceed the rate limit, the API returns a 429 Too Many Requests response:

{
  "error": {
    "code": "RATE_LIMIT_EXCEEDED",
    "message": "Too many requests. Please retry after 60 seconds.",
    "retryAfter": 60
  }
}

Best Practice: Implement exponential backoff when retrying requests after receiving a 429 response.