API Testing - WCF using Postman?

🙋 Questions
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Hi all, happy Friday.

I was wondering if anyone has had experience testing a WCF API with a SOAP Action, using Postman ?
Probably anyone under a certain age will wonder wth is WCF :smiley:

I am trying to test using Postman but keep running up against a 401.
This is the same when I try SOAPUI.
I wrote a quick test in .Net using HttpClient and get the expected Response.

I am trying to create a collection to give to Client’s, rather than writing an app that has to be maintained etc…

any hints or help would be greatly appreciated.

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Not gonna deny, I read the title and I’m googling it right now.
Then I saw that comment :rofl:

So for Postman SOAP requests I’m guessing you did:

  • Select method
  • enter URL
  • Added Headers (also the SOAPAction?)
  • Added a body and selected XML in the dropdown

Now you mentioned that you are getting a 401 which is Unauthorized.
I’m going to take the assumption that everything above is correct but just your token is invalid. Did you do your authentication flow also via postman or is it just something you fill in the headers?

I’m guessing you used the Beta version for NTLM auth?

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Hi Kristof, thanks for getting back.

To your advised steps, yes followed all of these.

I probably omitted to say, this is using OAuth2

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  1. What are the response headers that you receive from the 401?
  2. What version of Postman are you on?
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Content-Length 0
Server Microsoft-HTTPAPI/2.0
WWW-Authenticate Negotiate
Date Fri, 07 Feb 2025 11:36:07 GMT
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6

Weird question but can you update postman and run it as administrator and try it?

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not weird at all Kristof, i am clutching at big straws here :smiley:

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Upgraded to latest version v11.31.3 and running as Admin, but unfortunately still getting a 401.

About to get on a call with IT to see if they are perhaps blocking something with these 3P Tools

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Well I find a lot of stuff about NTLM resulting to 401 online even on the Postman forums. So I’m gonna call in the Hotline here @daniel.dainton :stuck_out_tongue:

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I think my problem is firmly in the WCF part, more than Postman or SoapUI.
Saying they support WCF is very different from actually supporting.
Bottom line, the APIs need replaced.

For now I will keep plugging away, but thanks for all your help. Very much appreciated

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Hey :wave:

It’s not really an API or Auth method that I’m hugely familiar with to be honest - my powers only stretch so far :sweat_smile:

Trying to to cross the streams here or pinch a topic from MoT but if you wanted to also raise this on https://community.postman.com I can take a look and if needed, grab someone from the team to get eyes on this too. :pray:

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Thanks, Daniel, I will do that.

cheers.

13

Try using WcfStorm, used this more than 5 years ago, but worked well with SOAP services when using the integrated authentication option.

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Thanks Raphael, I am looking at a number of Tools and will add this to my list.

My problem seems to be that the technology in these tools has moved on, these APIs have stood still for 20+ years

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:rofl: I’m guessing you haven’t found a solution then in Postman? ;(

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hi Kristof, unfortunately not. So looking at alternatives

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