# NameError: ApplicationAPI **URL:** \ **Category:** Ruby\ **Created:** [July 26, 2007, 6:20pm UTC](https://www.ruby-forum.com/t/nameerror-applicationapi/110479 "2007-07-26T18:20:59Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![markus](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/b782af/32.png) [@markus](https://www.ruby-forum.com/u/markus)\ **Post date:** [July 26, 2007, 6:20pm UTC](https://www.ruby-forum.com/t/nameerror-applicationapi/110479/1 "2007-07-26T18:20:59Z")
Just for the record… I’ve seen occasional mentions of a problem people have had upgrading existing Rails 1.1.x applications to Rails 1.2.x, leading to complete failure of the application with the message: NameError: Neither ApplicationApi or ApplicationAPI found …but I’ve never seen a general solution posted, or even an explanation of what caused it. (Google finds this: [http://weblog.oriontransfer.co.nz/articles/2007/04/12/rails-1-2-2-problem-with-older-engines](http://weblog.oriontransfer.co.nz/articles/2007/04/12/rails-1-2-2-problem-with-older-engines) but it appears not to have helped most people). Yesterday I ran into the problem myself and thought I should post the probable cause and likely fix for posterity. The problem: The older application has web services enabled but is not actually using / defining and web services (i.e., does not define the class ApplicationAPI). This was not a problem in earlier versions of Rails as the didn’t try to access the API if it wasn’t defined; later versions apparently assume that if you are using web services you have an API defined. What is likely to fix it: find the line(s) in config/environments.rb that disable unused frameworks and make sure that you are disabling web\_services: config.frameworks -= [:action\_web\_service, …] You may also need to check config/environments/\*.rb as the settings there would override those in environments.rb. –MarkusQ