Other way around, actually.  AppEngine came out in April 2008; Heroku in November 2007:<p><a href="https:&#x2F;&#x2F;web.archive.org&#x2F;web&#x2F;20071105005403&#x2F;http:&#x2F;&#x2F;heroku.com&#x2F;" rel="nofollow">https:&#x2F;&#x2F;web.archive.org&#x2F;web&#x2F;20071105005403&#x2F;http:&#x2F;&#x2F;heroku.com...</a><p>It&#x27;s fairly likely they were working on them in parallel without knowledge of each other, though.