Following users is one of the most foundational actions on Twitter.
We offer two sets of endpoint groups to help you lookup, create, and delete follow relationships: follows lookup and manage follows.
The follows lookup endpoints enable you to explore and analyze relationships between users, which is sometimes called network analysis. Specifically, there are two REST endpoints that return user objects representing who a specified user is following, or who is following a specified user.
You can authenticate this endpoint with either OAuth 1.0a User Context, App only, or OAuth 2.0 Authorization Code with PKCE. You can request up to 1,000 users per request, and pagination tokens will be provided for paging through large sets of results.
The manage follows endpoints enable you to follow or unfollow users.
Since you are making requests on behalf of a user, you must authenticate these endpoints with either OAuth 1.0a User Context or OAuth 2.0 Authorization Code with PKCE, and utilize the user Access Tokens associated with the user you are making the request on behalf of. You can generate this user Access Token using the 3-legged OAuth flow (OAuth 1.0a) or using the Authorization Code with PKCE grant flow (OAuth 2.0).
You are limited to 400 follow actions per day on behalf of each authenticated user, and will be limited to 1,000 actions per day per App across all of your authenticated users. For example, if you have five authenticated users, you can follow 400 users per day (per user limit) with two of those users for a total of 800 actions, and will have to split the remaining 200 actions (per app) amongst the remaining three users. This limit does not apply to the unfollow endpoint, which has a separate limit of 500 actions per day (per app).