SOAP vs. RESTful APIs in Vertex Tax: A Seamless Integration Approach

When it comes to tax compliance, having a reliable integration with third-party tax services is critical for ensuring accurate calculations and seamless business operations. Vertex, a leading tax technology provider, offers two primary ways to integrate: SOAP and RESTful APIs.

In this post, we’ll explore the key differences between these two API types, their use cases, and when you should choose one over the other for a Vertex tax integration.

SOAP API Documentation: Vertex SOAP API
RESTful API Documentation: Vertex RESTful API

SOAP vs. RESTful: The Basics

Before diving into the specifics, it’s important to understand what differentiates SOAP from RESTful APIs.

• SOAP (Simple Object Access Protocol): SOAP is a protocol-based API that uses XML for communication between the client and server. It supports more complex operations and includes built-in standards for error handling, security (WS-Security), and transaction management.

• REST (Representational State Transfer): REST is an architectural style that uses standard HTTP methods (GET, POST, PUT, DELETE) and can support JSON format. It is more flexible, lightweight, and faster for most integration needs.

Key Differences Between SOAP and RESTful APIs in Vertex Tax

1. Protocol and Message Format

• SOAP API: Uses strict XML formatting, and the entire message is contained in a SOAP envelope, making it more verbose.
   
• RESTful API: Typically uses JSON for request and response payloads, making it lighter and easier to work with.
   

2. Complexity and Flexibility

• SOAP API: Designed for complex operations like asynchronous messaging, distributed transactions, and more robust error handling.
   
• RESTful API: Easier to implement for simpler tasks and more flexible in terms of operations. It’s ideal for CRUD (Create, Read, Update, Delete) operations.
   

3. Performance Considerations

• SOAP API: Due to the overhead of XML formatting and strict specifications, SOAP calls tend to be slower, especially over unreliable networks.
   
• RESTful API: Leaner and faster due to smaller payloads (often JSON-based), which means better performance in most cases.
   

4. Error Handling and Security

• SOAP API: Has built-in standards for error handling and security, making it suitable for high-security environments.
   
• RESTful API: Depends on HTTP status codes for error handling and requires additional measures for security, such as OAuth or HTTPS.
   

SOAP in Vertex Tax: When to Use It

SOAP APIs are ideal when you require advanced features, such as:

• Complex Workflows: For scenarios where multiple operations need to be executed as a single transaction.
   
• Enterprise Integrations: SOAP’s strict protocol is beneficial when integrating with legacy enterprise systems that already use SOAP.
   
• Increased Security: If data security is a primary concern, SOAP’s built-in WS-Security provides an additional layer of protection.
   

Example Use Case:
When performing detailed tax calculations for large-scale enterprises, where transaction integrity and error handling are crucial.

RESTful API in Vertex Tax: When to Use It

RESTful APIs are a good choice when:

• Speed and Scalability: REST’s lightweight nature makes it a better option for high-speed operations and web-scale applications.
   
• Microservices and Cloud: REST’s compatibility with modern architectures like microservices and cloud-based solutions makes it ideal for these environments.
   
• Ease of Use: RESTful APIs are easier to consume and integrate with modern frameworks, making them a go-to choice for new projects.
   

Example Use Case:
For a web-based eCommerce platform that needs quick and frequent tax calculations for every transaction without the overhead of SOAP’s strict rules.

Integration Examples: SOAP vs. RESTful in Action

Let’s see how integrating with the Vertex Tax API differs for SOAP and RESTful approaches:

SOAP API Integration: Sample Request

<soap-env:Envelope xmlns:soap-env="http://schemas.xmlsoap.org/soap/envelope/">
    <soap-env:Body>
        <ns0:VertexEnvelope xmlns:ns0="urn:vertexinc:o-series:tps:9:0">
            <ns0:Login>
                <ns0:TrustedId>your-trusted-id</ns0:TrustedId>
            </ns0:Login>
            <ns0:QuotationRequest documentNumber="11234" documentDate="2024-01-01" transactionId="11234" transactionType="SALE">
                <ns0:Currency isoCurrencyCodeAlpha="USD" />
                <ns0:Customer>
                    <ns0:Destination>
                        <ns0:StreetAddress1>4217 Stacy Blvd</ns0:StreetAddress1>
                        <ns0:StreetAddress2></ns0:StreetAddress2>
                        <ns0:City>NC</ns0:City>
                        <ns0:MainDivision>NC</ns0:MainDivision>
                        <ns0:PostalCode>28209</ns0:PostalCode>
                        <ns0:Country>US</ns0:Country>
                    </ns0:Destination>
                </ns0:Customer>
                <ns0:LineItem lineItemNumber="1" locationCode="C" vendorSKU="SKU">
                    <ns0:Seller>
                        <ns0:Company>DST</ns0:Company>
                        <ns0:PhysicalOrigin>
                            <ns0:StreetAddress1>4217 Stacy Blvd</ns0:StreetAddress1>
                            <ns0:StreetAddress2></ns0:StreetAddress2>
                            <ns0:City>NC</ns0:City>
                            <ns0:MainDivision>NC</ns0:MainDivision>
                            <ns0:PostalCode>28209</ns0:PostalCode>
                            <ns0:Country>US</ns0:Country>
                        </ns0:PhysicalOrigin>
                    </ns0:Seller>
                    <ns0:Product productClass="">Glinteco-Product</ns0:Product>
                    <ns0:Quantity unitOfMeasure="UOM">1.0</ns0:Quantity>
                    <ns0:Freight>0</ns0:Freight>
                    <ns0:UnitPrice>205.0</ns0:UnitPrice>
                    <ns0:ExtendedPrice>205.0</ns0:ExtendedPrice>
                    <ns0:Discount />
                </ns0:LineItem>
            </ns0:QuotationRequest>
        </ns0:VertexEnvelope>
    </soap-env:Body>
</soap-env:Envelope>

RESTful API Integration: Sample Request

json

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{ "customer": { "id": "CUST12345", "businessLocation": { "country": "US", "postalCode": "10001" } }, "lineItems": [ { "product": { "code": "PRD001" }, "quantity": 2, "unitPrice": 100 } ], "currency": "USD", "transactionType": "sale" }

Pros and Cons of SOAP and RESTful APIs in Vertex Tax

Conclusion: Choosing the Right Approach

Choosing between SOAP and RESTful APIs depends on the specific needs of your project:

• Opt for SOAP if you need strong security, transaction management, or compatibility with enterprise systems.
• Go with RESTful if you value simplicity, speed, and modern web architecture compatibility.

Understanding these differences will help you integrate Vertex Tax services more effectively, providing a seamless and efficient solution for your business needs.