[Solved]-Heroku: No default language could be detected for this app for python even with runtime.txt



A possible solution to this problem can be specifying the buildpack during app creation like :

$ heroku create myapp --buildpack heroku/python

or after app creation like:

$ heroku buildpacks:set heroku/python

Refer Docs : Heroku Docs

The other problem I figured was that I had unnecessary package.json and other files in my django project. I solved it by removing unnecessary files from my app directory.
Since these files were obstructing the automatic detection of buildpack.

Another reason of failed detection could be wrong folder structure of your app. The Procfile and other heroku files should be right at the start of the git directory otherwise your app won’t get detected.

πŸ‘€Rajan Chauhan


  1. in your git bash : echo "python-3.7.0" > runtime.txt (adds runtime.txt file in your root directory with instructions to use python v3.7.0 by Heroku)
  2. git add .
  3. git commit -am "another commit"
  4. git push heroku master


As for the documentation:

Heroku automatically identifies your app as a Python app if any of the following files are present in its root directory:

  • requirements.txt
  • setup.py
  • Pipfile

You can solve that with pip freeze > requirements.txt, for example.


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