Salesforce terms starting with X

XML (Extensible Markup Language) is the structured text format Salesforce uses for SOAP API payloads, metadata definitions, package manifests, and several integration endpoints. Each XML document is a tree of named tags with attributes and nested content, validated against a schema (XSD or WSDL) that defines the allowed structure. Salesforce ships every metadata file (custom objects, Apex classes, page layouts, profiles) as XML, which is why the Salesforce CLI, change sets, and source-driven development all read and write XML under the hood. XML in the Salesforce ecosystem appears in three primary places. The first is the Metadata API and Tooling API, which serialize org configuration as XML for retrieval and deployment. The second is the legacy SOAP API, where every request and response is an XML SOAP envelope. The third is integration endpoints that exchange XML payloads with external systems (older ERP, BizTalk, financial systems). Modern Salesforce REST and most new integrations use JSON instead, but XML remains the canonical format for metadata work because Salesforce DX, sfdx-project.json builds, and every package manifest still expect XML files.