SOAP vs REST — Key Differences and When to Use Each

Posted by Vinay Vernekar 9th January 2026

Overview

SOAP and REST are two widely used web service architectures for building APIs. Understanding the differences between them helps you choose the right integration approach for Salesforce projects and other enterprise systems.

High-level comparison

Below are the key differences presented for quick scanning and SEO clarity:

Protocol and Style

SOAP (Simple Object Access Protocol) is a protocol with strict standards defined by W3C. It relies on XML messaging and has a defined envelope format.
REST (Representational State Transfer) is an architectural style that uses standard HTTP methods and can exchange data in multiple formats (JSON, XML, plain text). REST is not a protocol — it’s a set of constraints for designing networked applications.

Message format

SOAP: XML-only messages wrapped in a <soap:Envelope>. Built-in error handling and a header/body structure.
REST: Typically JSON (preferred for modern web/mobile apps) or XML. Simpler payloads and easier to parse.

Transport

SOAP: Usually uses HTTP(S), but can also use SMTP, TCP, or JMS. The envelope abstracts the transport layer.
REST: Uses HTTP/HTTPS and relies on HTTP verbs (GET, POST, PUT, PATCH, DELETE) to represent operations.

Standards, Security, and Features

SOAP: Rich standards stack — WS-Security, WS-AtomicTransaction, WS-ReliableMessaging. Strong built-in support for security, transactions, and formal contracts (WSDL). Ideal for enterprise scenarios requiring advanced security and reliable messaging.
REST: Leverages existing web security (TLS/HTTPS, OAuth 2.0, JWT). Less formal but simpler to implement. Security and transaction management are typically handled at the application layer.

Statefulness

SOAP: Can be stateful (supports built-in stateful operations) though often used statelessly.
REST: Designed to be stateless — each request contains all information required by the server to process it.

Performance and Bandwidth

SOAP: More verbose due to XML and envelope overhead. Might be slower and consume more bandwidth.
REST: Usually faster and lighter, especially when using JSON. Better suited for mobile and web apps where bandwidth and latency matter.

Use-cases and When to Use Which

Use SOAP when:

  • You require formal contracts and strong typing (WSDL).
  • Advanced WS-* features like WS-Security, transactions, or reliable messaging are needed.
  • Integrating with legacy enterprise systems that mandate SOAP.

Use REST when:

  • You need a lightweight API for web or mobile clients.
  • You prefer JSON and faster response times.
  • You want simpler, resource-oriented endpoints that map to HTTP verbs.

Salesforce Context

Salesforce supports both SOAP and REST APIs:

  • Salesforce SOAP API: Good for enterprise integrations that need WSDL-based clients, strong typing, and complex operations.
  • Salesforce REST API: Preferred for mobile and modern web apps, connected apps using OAuth, and lightweight integrations.

Example Requests

SOAP request (simplified):

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:urn="urn:partner.soap.sforce.com">
<soapenv:Header/>
<soapenv:Body>
<urn:login>
<urn:username>[email protected]</urn:username>
<urn:password>passwordTOKEN</urn:password>
</urn:login>
</soapenv:Body>
</soapenv:Envelope>

REST request (curl example):

curl -X GET \
-H "Authorization: Bearer <access_token>" \
https://yourInstance.salesforce.com/services/data/v57.0/sobjects/Account/001D000000IqhSL

Pros and Cons (Summary)

SOAP Pros: Standardized, feature-rich, strong security features, WSDL contract.
SOAP Cons: Verbose, steeper learning curve, heavier payloads.
REST Pros: Lightweight, easy to use, fast, JSON-friendly, better for web/mobile.
REST Cons: Less formal standards for advanced enterprise features; security/transactions must be implemented separately.

Conclusion

Choose SOAP for enterprise-grade integrations that need formal contracts, advanced security, and reliable messaging. Choose REST for lightweight, fast, and flexible APIs suitable for web and mobile applications. In Salesforce integrations, use the SOAP API when you need WSDL-driven, typed access; use the REST API for modern app flows and simpler integration needs.

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