Design Tinder

What are all possible Features

• User creates a profile

• login and authentication

• feed or recommendations of other user profiles

• User can swipe left, swipe right, or super like

• It's a match only if both swipe right

  • After match, conversation needs to be started within 24 hours to remain connected

  • Only female can initiate the conversation

• option to message

  • text messages

  • share images / videos over messsages

  • Monitoring of type of messages / vulgarity

• Option to unmatch user

• Push notification (in case of a match and inactive)

• buy premium subscription, and get additional features

• payment system

• user settings: filters basis geography, age and others

Narrowing down the problem statement

Functional Requirements

• User profile creation, and setting for recommendations

• Get other user profile recommendations

• Options to swipe right and left, and get a match

• non-premium account get limited number of swipes

Non Function Requirements

• Scalability

• low latency

• read-heavy app

• security - DDOS attack handling / rate limiter

Understanding the Scale

Traffic

• Total number of users = 50 Million

• Number of daily active users (DAU) = 1 Million DAU

• Number of new profiles created every day = 500 Thousand

• Total number of swipe every day = 100 * 1 Million = 1 Billion per day

• Total number of matches per day = 10 Million per day

Storage Requirements

• For images = 200 kb * 6 images per user * 50 Million users = 600 TB

Data Model

	Swipe transaction	Swipe Data
user_id	user_id	user_id
basic details	recomm_profile_user_id	date
image folder url	date time	total swipe count
enum(right swipe)	right/left/super	right swipe count
enum(left swipe)		super swipe count
enum (matches)		user type (basic / prem)
preferences {location, age range, gender (m,f,both)}

System Design

Design Considerations

Building Microservices

• Recommendation Engine

  • Based on current preference filters

  • Only those which have not been swiped right or left in past

  • Only active users (example: who have been active in last 5 days)

  • Show less profiles to those getting a lot of matches

  • Collaborative grouping

  • Do you reply or not

  • full text similarity between profiles

Design Diagram

Resources

• https://www.youtube.com/watch?v=nBdTBDJNOh8

• https://www.youtube.com/watch?v=iyLqwyFL0Zc&list=PLrtCHHeadkHp92TyPt1Fj452_VGLipJnL&index=38