How to override Strapi Admin panel endpoints?

In the admin panel - I have a content-type products, which shows me all the products in the database (MongoDB)

Suppose I would like to edit a product and when I click on the Save button, I would like to hit a custom API/ override the existing endpoint that updates my products collection!

Is it possible to customize or override the admin panel APIs?

Update(v4): Judging by the comments - this answer is now outdated as things have changed for v4.

The Strapi admin(strapi-admin) and Content manager(strapi-plugin-content-manager) are defined separately.

If you'd like to override/extend the endpoints; do so by defining the functions you want to override like so:

Locate the controller at:

extensions/<plugin-name>/controllers/<controller-to-override-name>.js

Example:

extensions/content-manager/controllers/ContentManager.js

Notice that the "strapi-plugin" part of the name was dropped!

Example of how to override and extend in controller file:

'use strict';
module.exports = {
  
  //this is how you destroy count
  async count(ctx) {
    ctx.body = {
      count: 99
    };
  },
  //this is how you extend
  async aFuncThatDoesntExistInOriginalController(ctx) {
     //add logic
  },
};

If you're extending you must add a mapping from route to controller & method
To see which endpoint is mapped to which method in the controller check out:

node_modules/<plugin-name>/config/routes.json
node_modules/strapi-plugin-content-manager/config/routes.json

Some basic info in docs: controllers, customization1 & customization2 and FAQ