---
title: "What is IndexedDB and how is it different from localStorage?"  
description: "What is IndexedDB and how is it different from localStorage?"  
author: "ICSM Computer"  
published: 2025-07-01  
updated: 2025-07-01  
canonical: https://www.mindstick.com/interview/34299/what-is-indexeddb-and-how-is-it-different-from-localstorage  
category: "database"  
tags: ["indexeddb"]  
reading_time: 4 minutes  

---

# What is IndexedDB and how is it different from localStorage?

**IndexedDB** and **localStorage** are both client-side storage solutions in the browser, but they serve different purposes and are fundamentally different in capability, structure, and use cases.

## What is IndexedDB?

**IndexedDB** is a **low-level API** for storing large amounts of **structured data** (objects, arrays, blobs) directly in the browser. It’s **asynchronous**, supports **indexes**, and can handle **complex queries and transactions**.

It is ideal for:

- Offline apps
- Storing JSON objects or binary data
- Sync queues
- Progressive Web Apps (PWAs)

## IndexedDB vs localStorage — Comparison Table

| Feature | `IndexedDB` | `localStorage` |
| --- | --- | --- |
| **Data type** | Stores objects, arrays, blobs, files | Only stores strings |
| **Size limit** | ~50MB or more (browser-dependent) | ~5MB per origin |
| **Async / Sync** | **Asynchronous (non-blocking)** | **Synchronous (blocking)** |
| **Structure** | Hierarchical: DB → Object Stores → Records | Flat key-value store |
| **Indexing** | Yes, can create indexes on properties | No indexing |
| **Transactions** | Yes, supports transactions | No |
| **Binary data** | Can store Blobs and Files | Not supported |
| **Performance** | Fast and optimized for larger data | OK for very small data only |
| **Use case** | Offline-first apps, PWA sync, queues, etc. | Simple key-value config (e.g. theme) |

## Example Use Cases

### localStorage

```javascript
localStorage.setItem("username", "john123");
console.log(localStorage.getItem("username")); // "john123"
```

Use for:

- Dark mode setting
- User's language preference

### IndexedDB

```javascript
const request = indexedDB.open("UserDB", 1);
request.onupgradeneeded = (e) => {
  const db = e.target.result;
  db.createObjectStore("users", { keyPath: "id" });
};
request.onsuccess = () => {
  const db = request.result;
  const tx = db.transaction("users", "readwrite");
  const store = tx.objectStore("users");
  store.add({ id: 1, name: "John", age: 30 });
};
```

Use for:

- Caching API responses
- Queueing offline form submissions
- Storing user profile objects

## Key Takeaways

- Use **IndexedDB** for large, structured, or relational data.
- Use **localStorage** for tiny, simple config-like string data.
- Avoid `localStorage` for performance-critical or offline-first apps.

## Answers

### Answer by ICSM Computer

**IndexedDB** and **localStorage** are both client-side storage solutions in the browser, but they serve different purposes and are fundamentally different in capability, structure, and use cases.

## What is IndexedDB?

**IndexedDB** is a **low-level API** for storing large amounts of **structured data** (objects, arrays, blobs) directly in the browser. It’s **asynchronous**, supports **indexes**, and can handle **complex queries and transactions**.

It is ideal for:

- Offline apps
- Storing JSON objects or binary data
- Sync queues
- Progressive Web Apps (PWAs)

## IndexedDB vs localStorage — Comparison Table

| Feature | `IndexedDB` | `localStorage` |
| --- | --- | --- |
| **Data type** | Stores objects, arrays, blobs, files | Only stores strings |
| **Size limit** | ~50MB or more (browser-dependent) | ~5MB per origin |
| **Async / Sync** | **Asynchronous (non-blocking)** | **Synchronous (blocking)** |
| **Structure** | Hierarchical: DB → Object Stores → Records | Flat key-value store |
| **Indexing** | Yes, can create indexes on properties | No indexing |
| **Transactions** | Yes, supports transactions | No |
| **Binary data** | Can store Blobs and Files | Not supported |
| **Performance** | Fast and optimized for larger data | OK for very small data only |
| **Use case** | Offline-first apps, PWA sync, queues, etc. | Simple key-value config (e.g. theme) |

## Example Use Cases

### localStorage

```javascript
localStorage.setItem("username", "john123");
console.log(localStorage.getItem("username")); // "john123"
```

Use for:

- Dark mode setting
- User's language preference

### IndexedDB

```javascript
const request = indexedDB.open("UserDB", 1);
request.onupgradeneeded = (e) => {
  const db = e.target.result;
  db.createObjectStore("users", { keyPath: "id" });
};
request.onsuccess = () => {
  const db = request.result;
  const tx = db.transaction("users", "readwrite");
  const store = tx.objectStore("users");
  store.add({ id: 1, name: "John", age: 30 });
};
```

Use for:

- Caching API responses
- Queueing offline form submissions
- Storing user profile objects

## Key Takeaways

- Use **IndexedDB** for large, structured, or relational data.
- Use **localStorage** for tiny, simple config-like string data.
- Avoid `localStorage` for performance-critical or offline-first apps.


---

Original Source: https://www.mindstick.com/interview/34299/what-is-indexeddb-and-how-is-it-different-from-localstorage

Copyright © MindStick Software Pvt. Ltd. This Markdown version is provided for developers, AI systems, and offline reading.