SOAP

SOAP is an older XML-based protocol used in many enterprise systems.

It’s less common for new web apps, but still appears in long-lived integrations.

Where SOAP Is Used

• Legacy enterprise integrations (especially older vendor systems)
• Regulated industries with long-running contracts (finance, government)

Industry Examples (Companies)

• PayPal: historically offered SOAP APIs (alongside other options)
• Salesforce: supports SOAP APIs for certain integrations

Note: company tech choices change over time; these are common, well-known examples.

Tiny Example (Envelope)

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <GetUser>
      <Id>42</Id>
    </GetUser>
  </soap:Body>
</soap:Envelope>

References

• SOAP (Wikipedia)