SOAP & WCF, enough to be credible
The protocol, WSDL, WS-Security, WCF, and — most importantly — how you consume a legacy SOAP service from modern .NET and put a clean REST API in front of it. 32 questions across 4 modules in 2 categories, plus a cheat sheet and flashcards.
The Fast refresher is the whole of SOAP in bullet points and tables — message structure, 1.1 vs 1.2, the 5 parts of WSDL, WCF bindings, .NET Core, security, SOAP vs REST, 10 quick Q&A and the multiple-choice traps. One page, printable. The four modules below are the same material with worked examples and traps if you want the depth.
Why this tutorial is short
Nobody is hiring you to write new SOAP services. SOAP appears in the job description because there is an existing service you'll have to talk to. So the goal here isn't depth — it's being able to discuss the protocol without hesitating, and then showing you know the modern way to integrate with it. Module 04 is the one that wins the question.
| If you have… | Do this |
|---|---|
| 3 hours | All four modules in order — it's only 32 questions. |
| 1 hour | Module 01 (envelope, fault, WSDL) and Module 04 (calling SOAP from .NET Core, the REST facade). |
| 20 minutes | Cheat sheet, then rehearse the "have you worked with SOAP?" answer at the end of Module 04 out loud. |
The one question to be ready for
"We have a legacy SOAP service and a React frontend. How would you connect them?" The answer is a .NET Core REST facade: generate a client from the WSDL, map the XML types to clean JSON DTOs, add caching and Polly retries because legacy systems are slow and fragile, keep the SOAP credentials in Key Vault, and authenticate the React app with JWT. The frontend never sees XML, and when the legacy service is retired only the facade changes. Module 04, Q30 walks through it with code.
"Is SOAP encrypted?" — no, not by itself (Module 02). "Is WCF with webHttpBinding still SOAP?" — no, that's REST over the WCF stack (Module 03). "Can you host a WCF service on .NET 8?" — not WCF itself; you use CoreWCF or SoapCore (Module 04). Each one is checking whether you actually know the boundary or are repeating slogans.
The sidebar search covers all 32 questions from any page — try "envelope", "fault", "WSDL", "WS-Security", "binding", "svcutil", "SOAPAction". Results link straight to the answer.