📅Week-4 (Day3) - Step-by-Step Guide to Creating a Spotify-Style Music App

NOTE: - I started my 8-week system design journey with Coder Army. I will be journaling every day, recording what I learn, reflecting on it, and sharing it with my network to help newcomers to system design.

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💠Functional Requirements (Real-life Example Style)

Let’s say you’re chilling with your headphones on and using Spotify. What all can you do? 🎧

Here's what we expect:

• ▶️ Play/Pause Songs

  • (Imagine tapping the play button on "Kesariya" and later pausing it when someone calls you)

• 📁 Create and Manage Playlists

  • (Like making a "Morning Motivation" playlist and adding 10 songs to it)

  • Play it sequentially, in shuffle mode, or your custom order.

• 🔊 Support Multiple Output Devices

  • Play music on:

    • Bluetooth speakers 📻

    • Wired headphones 🎧

    • Smart speakers 🗣️

    • Car stereo via AUX 🚗

(Hindi: Aap Spotify se music kahin bhi aur kisi bhi device par chala sakte ho, chahe woh Bluetooth ho ya wired speaker!)

💠 Non-Functional Requirements (Simple Language with Emoji Twist)

These are more about how well your app performs, not what it does.

• Scalability

  • Imagine crores of users streaming songs at the same time.

  • Your app must handle huge traffic, like Diwali ke time sabhi party songs sun rahe ho!

• Extensibility

  • Tomorrow you want to add support for playing music on smart glasses or via gestures — you should be able to do that without breaking the current system.

💠How to Think Like a System Designer?

Let’s simplify Spotify into subsystems — like how you build a LEGO model one block at a time

🔗 Components You Might Need:

1. User Service – for sign up/login

2. Music Service – to store and fetch songs

3. Playlist Service – to manage user playlists

4. Streaming Service – to deliver songs in real time

5. Device Manager – to route audio to the selected output device

💠Real-Life Analogy: Restaurant

Spotify is like a restaurant:

• You (User) place the order (Choose song/playlist)

• Kitchen (Backend Services) prepares the dish (Stream the song)

• Waiter (Streaming Service) brings it hot to your table (device)

• You can eat (listen) from a plate, bowl, or takeaway (multiple devices)

(Hindi: Jaise restaurant mein aap order karte ho aur waiter aapke table pe khana serve karta hai — Spotify bhi waise hi backend se song lekar aapke device par play karta hai)

💠System Design Concepts to Use

• Microservices Architecture (Each feature in its own module)

• Load Balancer to handle many users

• CDN to deliver music fast

• Database (SQL for user data, NoSQL for playlists/songs)

💠Custom Play Order Feature (Smart Design Idea)

If a user wants to:

• Play in loop 🔁

• Play randomly 🔀

• Play specific song on mood (custom logic) 💃

...You need a smart Queue System that takes user inputs and reshuffles tracks accordingly.

💠Recap (English + Hinglish Style)

Spotify jaisa app banana mushkil nahi, agar design sahi ho!

Functional Requirements:

Gaana suno, playlist banao, aur kisi bhi device pe chalao.

Non-Functional:

App scalable aur future-ready ho.

Use microservices, CDN, smart queueing, and modular device support to make it a reality.

💠UML Diagram

💠Code : github

Week - 4 ( Day-3) Completed ✅ System Design

NOTE : - A big thanks to my mentors Rohit Negi Sir and Aditya Sir for launching this amazing 8-week course absolutely free on YouTube via CoderArmy9 :- youtube.com/@CoderArmy9 . 🙌

👉 Share this blog with your connections! Let’s keep learning, growing, and supporting one another on this journey. 🚀

✍️ Payal Kumari 👩‍💻

Jai Hind 🇮🇳 | #CoderArmy #LearningInPublic #SystemDesign #TechForAll #MentorshipMatters #8weeksLLdChallenge #LowLevelDesign #Code #LLD #OOP 👩‍💻