@higher_08 said:
Append detail of collection
I am using request /movie/ {movie id}.
As a result, there are collections to which the movie belongs.
BUT only their identifiers and name are there.
How can I add collection details (overview) here or do I have to make two requests?

Example: ```id: 258....,
"name": "collection name",
"poster_path": "path",
"backdrop_path": "path"

And I else need a _overview_ field  

Yes. Make 2 API Requests. Using your example.
For this film: https://www.themoviedb.org/movie/256-antoine-et-colette
This API Request for Movie details
https://api.themoviedb.org/3/movie/256?api_key=THE_KEY&language=en-US
In the reply you will see the Collection ID, 185682

adult   false
backdrop_path   "/ymtwNtiuZwbYa1Vetp68VOGgrw3.jpg"
belongs_to_collection   
id  185682
name    "The Adventures of Antoine Doinel"
poster_path "/66hyq0YtgBjrfT2kB1YJu33UDcy.jpg"
backdrop_path   null
budget  0
genres  

Then the API Request for the Collection details
See here https://developers.themoviedb.org/3/collections/get-collection-details
https://api.themoviedb.org/3/collection/185682?api_key=THE_KEY&language=en-US