Post to Sprout Forms plugin from an app or another website Is it possible to post a form to Sprout Forms in Craft 2 from a desktop app or another website?

The AJAX example in the docs mentions this - sproutForms/entries/saveEntry
What would the full URL be?

I did try http://domainname.com/sproutForms/entries/saveEntry but it gives an 404 error.

Thank you for reading this.
Assuming you're using a hidden action input, then sproutForms/entries/saveEntry should be correct.  You can see that in the Craft docs here: https://docs.craftcms.com/v2/plugins/controllers.html#posting-to-controller-actions

If you're not using that input, or you're constructing the URL to post to manually, then it will likely be actions/sproutForms/entries/saveEntry instead, assuming you have set a custom actionTrigger in your general config.