58. Design a Dating App like Tinder

The brief

Design a Dating App like Tinder. Stacks of nearby people in under 300 ms, 2 billion swipes a day, and a match never missed even when both like at once. Work from the scoping questions below. State assumptions for any unspecified load, guarantee or target, then trace your design end to end. Explain one difficult case and a credible alternative; the worked example is a reference, not a required implementation.

• Set the scope: Scale? Stack latency?
• Define the contract: How consistent is a match? How fresh must a stack be?
• Test the boundaries: Can a swiped profile come back? Who can appear in a stack? Who is notified? Photos, chat, paid features?

Constraints

Explicit scope and guarantees

Resolve the scoping questions for a Dating App like Tinder. Separate stated behavior from assumptions, and identify what is outside your design.

Supported operating targets

Declare relevant volume, latency, freshness, quality or cost targets with units. Show calculations or an evaluation plan that can test them; unspecified targets are your assumptions, not hidden pass criteria.

Failure and boundary behavior

Explain how your guarantees hold in a difficult case relevant to this subject. Address: Who is notified? Photos, chat, paid features?

What to cover

1. 01

   Scope and behavior contract

   Identify users, required behavior and exclusions. Answer: Scale? Stack latency?

2. 02

   State and interfaces

   Define the information owned by the system and the inputs, outputs and errors at its boundaries. Resolve: How consistent is a match? How fresh must a stack be?

3. 03

   Capacity and operating targets

   Estimate the dominant workload and resource demand with units and explicit assumptions. For a learned system, also state how quality is measured and what data is available.

4. 04

   Architecture and central flow

   Draw or describe the responsibilities needed for a Dating App like Tinder. Trace a representative request, event or job from its input to a visible result; identify durable state owners.

5. 05

   Failure and boundary walkthrough

   Walk through a difficult case step by step, including detection and recovery. Consider: Can a swiped profile come back? Who can appear in a stack? Who is notified? Photos, chat, paid features?

6. 06

   Tradeoffs and operations

   Compare a credible alternative using your chosen workload and guarantees. Explain a remaining risk, a signal to watch and when you would change the design.

Worked designs

Explore the architecture and decisions, then build on an example with Coach.

Official design

Design a Dating App like Tinder

Stacks of nearby people in under 300 ms, 2 billion swipes a day, and a match never missed even when both like at once: one-hour boards for junior, senior and staff, with the theory behind them.

Explore the design

Review rubric

AI feedback uses these criteria. Scores are practice feedback.