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# Overview

TaxCloud’s Sales Tax API is designed to plug into any ecommerce, order-management, or point-of-sale system. The real-time API flow is simple and modular, built around three main actions:

1. **Create a cart** to calculate a real-time sales tax calculation.
2. **(Optional)** Apply tax exemptions before converting the cart for reporting.
3. **Convert the cart into an order** after a successful payment.  

Each of these steps is covered in its own dedicated guide, allowing you to explore the implementation at your own pace and depth.

## Why Use This Flow

This integration pattern is designed to provide:

* **Real-time tax accuracy**, calculated down to the most basic level.  
* A **single source of truth** — the order object serves as your tax and audit record.  
* **Flexibility and scalability**, with support for refunds, multiple destinations, and marketplace scenarios as your needs evolve.

## Core API Endpoints

| Endpoint | When to Use | Typical Payload |
| ----- | ----- | ----- |
| /carts | Use during checkout to show a tax calculation. Calculate a tax calculation to display to the customer before they check out or complete the order. Call this whenever the cart changes. For e-commerce platforms, this concept corresponds to the customer’s shopping cart, but it can also be used in other contexts when you need to display a tax calculation before the order is finalized. When the customer checks out, convert the cart into an order. | Items, origin/destination, prices |
| /carts/orders | Call after order submission to convert the cart into an order and finalize the sale. | cartId, orderId, completed or completedDate (optional) |

## Integration Workflow

Here’s a step-by-step look at how to integrate TaxCloud into your checkout flow:

1. **Configure your TaxCloud account**  
    Set up your business profile, define nexus states, and register your business locations.  
    → See: [Setup & Authentication](https://docs.taxcloud.com/guides/getting-started/setup-and-authentication)

2. **Authenticate**  
    Use your API Key and ConnectionID to authenticate. You can verify your connection with the `ping` endpoint.

3. **Create a cart**  
    Each time a customer updates their cart (changes quantity, address, or items), create or update a cart via the API.  
    → See: [Calculate Tax with Carts](https://docs.taxcloud.com/guides/workflows/real-time-api/calculate-taxes-with-cart)

4. **(Optional) Attach an exemption certificate**  
    If the customer is tax-exempt, you can upload or auto-match an exemption certificate before finalizing the order.  
    → See: [Handling Exemptions](https://docs.taxcloud.com/guides/workflows/real-time-api/handle-exemptions)

5. **Convert the cart into an order**  
    Once payment is successful, convert the cart into an order using the orders endpoint.  
    → See: [Convert Carts to Orders](https://docs.taxcloud.com/guides/workflows/real-time-api/convert-carts-to-orders)

6. **Reconcile and file**  
    All completed orders automatically flow into your TaxCloud dashboard for filing and reporting.