Design Music Streaming Service like Spotify
Design a music streaming service like Spotify that allows users to search, play, and manage songs, create playlists, and stream music, using object-oriented design.
Spotify is a popular digital music streaming platform that gives users access to a vast library of songs, albums, podcasts, and audio content from artists and creators around the world.
It offers features such as:
- Searching and playing tracks on-demand
- Creating personalized playlists
- Following favorite artists or albums
- Streaming audio over the internet, either via an ad-supported free tier or an ad-free premium subscription
In this chapter, we will explore the low-level design of a Spotify like service in detail.
Lets start by clarifying the requirements:
1. Clarifying Requirements
Before starting the design, it's important to ask thoughtful questions to uncover hidden assumptions and better define the scope of the system.
Here is an example of how a conversation between the candidate and the interviewer might unfold:
Candidate: Should we support both free and premium users?
Interviewer: Yes. Free users should experience occasional ads during playback. Premium users should enjoy uninterrupted, ad-free listening.
Candidate: Do users interact only with individual songs, or can they also play albums and playlists?
Interviewer: Users should be able to play individual songs, albums, and playlists. These should be handled uniformly.
Candidate: Should users be able to follow artists and get notified when a new album is released?
Interviewer: Yes. Users can follow artists and should receive notifications whenever those artists release new albums.
Candidate: Should the music player support playback controls like play, pause, and next track?
Interviewer: Yes. The user should be able to control playback using these actions. The player should behave differently based on its current state (stopped, playing, paused).
Candidate: Is search functionality in scope?
Interviewer: Yes. Users should be able to search for songs by title and artists by name.
Candidate: Do we want to show song recommendations?
Interviewer: Yes. Include a simple recommendation engine. For now, simulate genre-based or randomized recommendations.
After gathering the details, we can summarize the key system requirements.
1.1 Functional Requirements
- Support both free and premium tiers for users
- Support adding songs, albums, playlists, and artists
- Allow users to play songs, albums, and playlists uniformly
- Support playback controls: play, pause, and skip (next track).
- Support creation and management of playlists (create, delete, add/remove songs)
- Allow users to search for songs by title or search for artists by name
- Generate song recommendations using pluggable strategies (e.g., genre-based, randomized).
1.2 Non-Functional Requirements
- Modularity: The system should be composed of well-defined modules
- Extensibility: The design should be flexible to allow future additions
- Maintainability: Code should be modular, easy to test, and cleanly organized