Flask and React Docker containers not communicating via Docker-Compose

Question

I have two containers - one containing a react app, another a flask app.

I can build both using the below docker-compose file and their respective Dockerfiles, and a

Answer 1

As LinPy and leopal in the comments pointed out 127.0.0.1 in package.json needed to be changed to reference the correct flask container.

"proxy": "http://middleware:5000",