UPDATE: Samling is live again at https://fujifish.github.io/samling/samling.html
Samling is a serverless SAML IdP for the purpose if testing any SAML SP endpoint. It supports AuthnRequest and LogoutRequest.
It runs solely in the browser to simulate SAML responses returned from a SAML IdP – no registration, no servers, just a browser. You can control many aspects of the response – from success to various failures.
Simply setup the target URL for the SAML IdP to be https://fujifish.github.io/samling/samling.html, and you’re done. If there is a SAMLRequest query param present on the request, Samling will parse, extract and populate the relevant fields.
If you don’t want to use the online version, you can clone the samling repo from https://github.com/fujifish/samling and host it yourself – all you will need is a static file server.