API Design

Define the APIs expected from the system. This is your chance to analyze and define the read and write paths so that you can come up with the high-level design...

1. POST /tweet

Purpose: create a new tweet

Input

user_id
content

Explanation

Used when a user posts a tweet
Triggers storage + fan-out to followers’ timelines

2. POST /follow

Purpose: follow a user

Input

follower_id
followee_id

Explanation

Updates social graph
Affects future timeline generation

3. POST /unfollow

Purpose: remove follow relationship

Input

follower_id
followee_id

Explanation

Removes content source from timeline

4. POST /favorite

Purpose: like a tweet

Input

user_id
tweet_id

Explanation

Records engagement
May update counters asynchronously

Read path

1. GET /timeline

Purpose: fetch user’s home feed

Input

user_id
pagination_cursor

Explanation

Returns list of tweets from followed users
Most critical, high-frequency API

2. GET /tweet/{id}

Purpose: fetch a single tweet

Explanation

Used when opening tweet detail

3. GET /user/{id}/tweets

Purpose: fetch tweets of a user

Explanation

Used for profile view

user action → API → process → store → fan-out → read from timeline → respond

Submissions

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