SOAP - ASMX services are the older ASP.NET Web Services

Yes — ASMX services are the older ASP.NET Web Services technology introduced with .NET Framework (around .NET 1.0/1.1). A quick breakdown:

• File Extension: They use the .asmx file extension (e.g., Service.asmx).

• Protocol: They expose SOAP (Simple Object Access Protocol) endpoints, typically over HTTP.

• Usage: Designed to let applications exchange data using XML-based SOAP messages.

• Implementation: You usually decorated methods with [WebMethod] inside a class that inherits from System.Web.Services.WebService.

• Discovery: A .asmx service automatically exposes a WSDL (Web Services Description Language) document for client generation.

• Limitations:

  • Tight coupling to SOAP/XML.

  • Not as flexible as later technologies (like WCF or REST/JSON).

  • Runs only on IIS and .NET Framework (not .NET Core / .NET 5+).

Legacy Status:

• Microsoft considers ASMX "legacy" and recommends WCF (Windows Communication Foundation) for SOAP services, or ASP.NET Web API / gRPC for modern service-oriented apps.

• ASMX still works in older .NET Framework apps but is not supported in .NET Core or .NET 6/7/8+.