Difference Between RPC and SOAP

RPC and SOAP are two methods for implementing remote procedure calls between distributed systems. SOAP is a protocol that encodes messages in XML and transports them through HTTP or HTTPS. Remote Procedure Call (RPC) is a protocol that allows a client application to call a remote server's method or function as if it were a local function call.

Read this article to find out more about RPC and SOAP and how they are different from each other.

What is RPC?

Remote Procedure Call (RPC) is a protocol that allows a client application to call a remote server's method or function as if it were a local function call. In other words, RPC provides a mechanism for invoking a remote system's method as if it were implemented locally.

  • When a client makes an RPC call, it sends a request message to the remote server, which then executes the requested method and returns a response message. After receiving the response message, the client resumes execution as if the method had been called locally.

  • RPC can be implemented using a variety of transport protocols, including TCP/IP, UDP, and HTTP. The client and server communicate through an interface specification that describes the methods and parameters that can be invoked remotely. Typically, an interface specification is written in a language-independent format such as IDL (Interface Definition Language) or WSDL (Web Services Description Language).

  • In distributed systems, RPC is commonly used to provide communication across different applications or components. It allows developers to create modular systems by breaking complex applications down into smaller, independent components that can run on multiple systems. RPC allows developers to construct systems that can extend horizontally by adding additional servers as the workload increases.

  • RPC has several limitations. It does not, for example, include built-in support for advanced features such as security, transactions, or message routing, which may be necessary in current distributed systems. In addition, RPC may require custom data serialization and deserialization to handle complex data types, which might complicate implementation.

What is SOAP?

SOAP is a messaging protocol that uses XML for message encoding and HTTP or HTTPS for transmission. It is a more complex and feature-rich protocol than RPC, providing a standardized method of sharing structured information between distributed systems, making it perfect for web services.

  • When a client sends a SOAP request, it generates an XML message containing the method name and parameters that will be executed on the remote server. The message is then sent to the remote server through HTTP or HTTPS, which processes the request and returns an XML message containing the method call result.

  • SOAP has a wide variety of features, including support for advanced security mechanisms like SSL, digital signatures, and encryption. It also supports transactions, allowing numerous tasks to be carried out as part of a single transaction. SOAP also supports message routing, which allows messages to be sent to various receivers based on established routing rules.

  • SOAP messages are defined using WSDL (Web Services Description Language), which provides a standard way of describing remote methods and parameters. The transport protocols, message formats, and security methods that can be used with SOAP are also defined by WSDL.

Difference Between RPC and SOAP

The following table highlights the major differences between RPC and SOAP −

Characteristics RPC SOAP
Encoding Binary XML
Transport Protocol TCP/IP, UDP, or HTTP HTTP or HTTPS
Message Format Structured data Structured data with metadata
Transactions Not supported Supported
Interface Definition Predefined interface definition, such as IDL Predefined interface definition, such as WSDL
Performance Faster and more efficient Slower and more complex
Complexity Simple and easy to implement More complex and harder to implement
Message Routing Not supported Supported
Security Basic authentication Advanced security mechanisms, such as SSL, WS-Security, and digital signatures


In conclusion, RPC and SOAP are two different protocols used to implement remote procedure calls between distributed systems. RPC is a simple and efficient protocol that communicates using binary encoding and low-level network protocols such as TCP/IP or UDP. It is suitable for basic client-server applications that do not require complex features like security, transactions, or message routing.

The decision between RPC and SOAP depends on the system requirements and the developers' specific needs. RPC may be the better option if the system is simple and does not require complex functionality. SOAP may be a superior option if the system is complex and requires advanced functionalities. Finally, both protocols offer advantages and disadvantages, and a decision should be made based on the application's specific requirements.

Updated on: 10-Aug-2023


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