Requirements

Functional Requirements:

• rich posts
• voting
• comments
• subreddits
• post relevance algorithm (feed)

Non-Functional Requirements:

• Should support a lot of users
• Should respond fast
• Should be resistent to errors
• Could have eventual consistency

Capacity Estimation

read to write ratio is about 50 to 21 for posts and comments, two times the reads

QPS is about 600.

Storage is

Bandwidth is

API Design

GET /posts/{post_id}

QUERY/POST /posts {ids: [...]}

PATCH /posts/{post_id}, body: {title, text, img_id, vote_id}

PUT /posts, body: {title, text}

GET /posts/{post_id}/comments

GET /comments/{comment_id}

PUT /comments, body: {post_id, parent_id, text}

PATCH /comments/{comment_id}, body: {text}

GET /feed/{cursor}

PUT /image/ {metadata}

PUT /image/{id}/file

GET /voting/{id}

PUT /voting/ {title, text, options}

PUT /voting/{id}/vote

GET /community/{id} -> {post_ids}

PUT /community/, {name, description, slug}

High-Level Design

Describe the overall system architecture. Identify the main components needed to solve the problem end-to-end. Use the diagramming tool to create a block diagram.

Database Design

Posts

id

title

text

voting_id

Comments

images

Communities

Votings

Votes

Detailed Component Design

Deep dive into 2-3 key components. Explain how they work, how they scale, discuss tradeoffs, capacity, and any relevant algorithms or data structures.