Apex Web Services

In plain words: REST is like sending a postcard (lightweight, JSON-formatted, quick to read), while SOAP is like sending a registered, tamper-evident envelope with a legal contract inside (strictly typed, XML-only, highly regulated). Salesforce supports both to let you connect any external system. Salesforce integrations rely on communication protocols that determine how external applications talk to your CRM data. While modern architectures favor lightweight, mobile-ready interfaces, legacy enterprise architectures demand strict contracts and strict data governance. The two primary protocols fulfilling these needs are REST (Representational State Transfer) and SOAP (Simple Object Access Protocol) .

In plain words: Salesforce SOAP Integration allows enterprise systems to exchange structured data with Salesforce using XML-based messages governed by a strict contract called a WSDL (Web Services Description Language). While REST is great for lightweight, flexible web apps, SOAP provides strict typing, formal contracts, and enterprise-grade reliability for banking, ERP, and legacy systems. Connecting Salesforce with on-premises infrastructure, financial hubs, and enterprise resource planning (ERP) platforms often requires a contract-first integration approach. SOAP (Simple Object Access Protocol) provides a rigid, XML-based messaging framework that guarantees data structure conformity, strict data typing, and reliable end-to-end communication across enterprise systems.

Exposing custom REST endpoints in Salesforce using the @RestResource annotation allows third-party systems to create, update, or query records in real time. While simple endpoints can map incoming JSON properties directly to method parameters, complex enterprise integrations often send nested JSON structures, line-item arrays, or dynamic payloads that require manual extraction and deserialization. In plain words: When external systems send deeply nested JSON or lists in an HTTP request, Apex method parameters fall short. Instead, you extract the raw JSON body using RestContext.request.requestBody and convert it into a strongly typed Apex wrapper class using JSON.deserialize() .