Design a short-form video recommendation & feed platform
PremiumML systemHard
- Recommendation pipeline
- Feed generation
- Real time ranking
Quick answer
This ML system interview question asks you to design a short-form video recommendation & feed platform. Aim for a design that turns data into useful predictions in production, then explain the data, training, serving and monitoring. Interviewers want to see how you frame the problem, measure success and keep the model healthy after launch.
The problem
Design a short-form video platform (similar to TikTok or Reels) that serves a personalized infinite-scrolling video feed to hundreds of millions of daily active users. When a user opens the app, the system must quickly assemble and rank a feed of short videos based on real-time user engagement (likes, skips, watch time). The platform must also ingest raw video uploads, encode them into multiple formats, and distribute them globally.
What must a short-form video recommendation & feed platform do?
- Feed Serving: Serve a personalized feed of video IDs and metadata for infinite scrolling.
- Engagement Ingestion: Inscribe user interactions (view, skip, like, watch duration) in real-time to update user preferences.
What scale should you design for?
Use these numbers in your estimates.
The scale numbers unlock with this questionUnlock
Key concepts
- Recommendation pipeline
- Feed generation
- Real time ranking
- Media streaming
- Event processing
- Distributed caching
How you’ll practise
- Problem framing
- Data and labels
- Features and model
- Training and evaluation
- Serving and monitoring
- Wrap-up
Lala, personalized to you, gives a hint when you ask and reviews your design when you are ready.
What do interviewers look for?
In any ML system design round.
- Frames the product goal as a clear ML problem
- Defines offline and online success metrics
- Explains where the data and labels come from
- Separates training from serving and keeps features consistent
- Plans for drift, retraining and rollbacks
- Weighs model quality against latency and cost
Questions people ask about this interview question
- Which design type is this question?
- It is an ML system question. You design a short-form video recommendation & feed platform and explain your choices the way you would in an interview.
- Is this question asked at entry level?
- It is marked Hard. It suits engineers preparing for senior interviews, where you are expected to drive the discussion and go deep on trade-offs.
- What should I cover first?
- Start with the product goal, how success is measured and what data is available. Agree on scope with the interviewer before you design anything.
- Can I practise it for free?
- It is a premium question. Sign up and unlock it once for 10 credits; it then stays unlocked. When you finish, Lala, your personalized AI mentor, can review your design for 30 credits.
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Updated · Written by the SevyDevy team