# Design a media search engine: system design interview question

> Text search across short metadata and long transcripts, with relevant results, timely catalog changes, and strict availability checks.

Source: https://sysround.com/questions/design-media-search-engine
Updated: 2026-11-05


Difficulty: hard. Levels: Senior, Staff+.

## How the interviewer opens it

"Design search for a large media catalog across titles, creators, descriptions, and transcripts. Return relevant results quickly as catalog content and availability rules change."

## What to clarify first

- Catalog size
- Traffic and read:write ratio
- Queries and result pages
- Latency and service availability
- Update freshness
- Availability rules
- Consistency versus availability
- Durability
- Relevance
- Scope boundaries

## Scope of a strong answer

Core requirements:

- Search titles, creators, descriptions, and transcripts.
- Return relevant media items with short text excerpts.
- Reflect catalog edits within the freshness target.
- Exclude items that current availability rules block.

Usually out of scope:

- Playback and media delivery
- Personal recommendations
- Semantic search and multiple languages
- Rights contract management
- Results beyond the first 100 matches

## What interviewers probe

### Relevance across text sources

Titles express direct intent, while long transcripts contain many incidental matches. A single score can favor the wrong source.

### Availability of search results

Search data can lag behind restrictions. Current checks also add work after text retrieval and can remove most leading matches.

### Search maintenance during catalog changes

Delayed events can restore old content or lose recent edits. Index replacement and active pagination sessions complicate the freshness contract.

## Common mistakes

- The design uses source catalog text scans at the stated query rate.
- The design gives every text field the same weight.
- The design trusts search data or cached responses to enforce current availability.
- The design writes the catalog and search engine separately without recovery.
- The design replaces an index without replaying edits and deletes.
- The design keeps pagination sessions indefinitely despite the freshness contract.

## The bar by level

- **Senior:** Handles delayed events, deletes, and index replacement. Bounds candidate checks and excerpt work. Tests relevance changes. Accounts for freshness, cache lifetime, and session expiry.
- **Staff+:** Defines precise freshness and authorization contracts. Sizes policy checks and shard fan-out. Explains failure behavior during index replacement and active sessions. Evaluates regional failure trade-offs.

Practice this question with an AI interviewer: https://sysround.com/practice/new?problem=media-catalog-search


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SysRound (https://sysround.com) is an AI practice tool for system design interviews. It has a voice or typed AI interviewer and a shared whiteboard. At the end, you get feedback on each skill and a model answer. The AI feedback can be wrong.