---
title: "How does IndexedDB compare to WebSQL and localStorage?"  
description: "How does IndexedDB compare to WebSQL and localStorage?"  
author: "Shalini Passi"  
published: 2025-07-04  
updated: 2025-07-04  
canonical: https://www.mindstick.com/interview/34317/how-does-indexeddb-compare-to-websql-and-localstorage  
category: "database"  
tags: ["database", "indexeddb"]  
reading_time: 5 minutes  

---

# How does IndexedDB compare to WebSQL and localStorage?

[IndexedDB is the **modern**](https://www.mindstick.com/interview/34289/what-is-indexeddb)**, recommended** way to store structured data in the browser. Here's a clear comparison between [**IndexedDB**](https://www.mindstick.com/interview/34291/how-does-indexeddb-work), **WebSQL**, and [**localStorage**](https://www.mindstick.com/interview/1548/what-is-the-use-of-localstorage-in-html5), including their features, support, and limitations:

| Feature | IndexedDB | WebSQL (Deprecated) | localStorage |
| --- | --- | --- | --- |
| Data Size Limit | Hundreds of MBs+ | ~5–50 MB (varies) | ~5–10 MB |
| Structure Support | Structured objects | Relational only (SQL) | String-only |
| Async API | Yes (event or promise) | Async but SQL-based | No, it's synchronous |
| Binary Data Support | Yes (Blobs, Files) | Yes (via base64 hacks) | No |
| Query Type | Indexed (No SQL) | SQL Queries (Relational) | Key-value only |
| Performance | Excellent for large data | Moderate | Poor for large data |
| Multi-store support | Yes (Object Stores) | Tables | No |
| Transactions | Yes | Yes | No |
| Browser Support | All modern browsers | Deprecated in all | All |
| Offline support | Yes | Yes | Yes |

## 1. IndexedDB

- Stores **structured data** (objects, files, blobs).
- Uses **object stores** (like tables) and **indexes** for fast lookups.
- **Asynchronous API** (event-based or promise-based via wrappers like `idb`).
- Built for **complex, large-scale offline storage**.
- **Binary-safe** and scalable.
- **Recommended for modern apps** that need structured, reliable offline storage.

## 2. WebSQL (Deprecated)

- Uses **SQL** for querying (like SQLite).
- Good for relational data, but:

   - **Deprecated by W3C**: no new features, limited future support
   - Not available in some environments (e.g., Firefox, Safari 16+)

- Only useful for legacy apps.
- **Avoid using WebSQL** in new projects.

## 3. localStorage

- Simple **key-value storage** (strings only).
- **Synchronous API** — blocks the main thread.
- Good for small settings or flags (theme, token, etc.).

```javascript
localStorage.setItem("token", "abc123");
const token = localStorage.getItem("token");
```

- Not suitable for storing large data or binary files.

## Use Case Summary

| Use Case | Recommended Storage |
| --- | --- |
| User settings, theme, token | `localStorage` |
| Large datasets (e.g., messages, images) | `IndexedDB` |
| Offline-first apps (PWA, sync cache) | `IndexedDB` |
| Legacy apps using SQL | `WebSQL` (avoid now) |
| Saving files/blobs | `IndexedDB` |

## Conclusion

> **Use** `IndexedDB` **for anything beyond simple string values.**

It is:

- Modern
- Asynchronous
- Structured
- Efficient
- Fully supported

## Answers

### Answer by Shalini Passi

[IndexedDB is the **modern**](https://www.mindstick.com/interview/34289/what-is-indexeddb)**, recommended** way to store structured data in the browser. Here's a clear comparison between [**IndexedDB**](https://www.mindstick.com/interview/34291/how-does-indexeddb-work), **WebSQL**, and [**localStorage**](https://www.mindstick.com/interview/1548/what-is-the-use-of-localstorage-in-html5), including their features, support, and limitations:

| Feature | IndexedDB | WebSQL (Deprecated) | localStorage |
| --- | --- | --- | --- |
| Data Size Limit | Hundreds of MBs+ | ~5–50 MB (varies) | ~5–10 MB |
| Structure Support | Structured objects | Relational only (SQL) | String-only |
| Async API | Yes (event or promise) | Async but SQL-based | No, it's synchronous |
| Binary Data Support | Yes (Blobs, Files) | Yes (via base64 hacks) | No |
| Query Type | Indexed (No SQL) | SQL Queries (Relational) | Key-value only |
| Performance | Excellent for large data | Moderate | Poor for large data |
| Multi-store support | Yes (Object Stores) | Tables | No |
| Transactions | Yes | Yes | No |
| Browser Support | All modern browsers | Deprecated in all | All |
| Offline support | Yes | Yes | Yes |

## 1. IndexedDB

- Stores **structured data** (objects, files, blobs).
- Uses **object stores** (like tables) and **indexes** for fast lookups.
- **Asynchronous API** (event-based or promise-based via wrappers like `idb`).
- Built for **complex, large-scale offline storage**.
- **Binary-safe** and scalable.
- **Recommended for modern apps** that need structured, reliable offline storage.

## 2. WebSQL (Deprecated)

- Uses **SQL** for querying (like SQLite).
- Good for relational data, but:

   - **Deprecated by W3C**: no new features, limited future support
   - Not available in some environments (e.g., Firefox, Safari 16+)

- Only useful for legacy apps.
- **Avoid using WebSQL** in new projects.

## 3. localStorage

- Simple **key-value storage** (strings only).
- **Synchronous API** — blocks the main thread.
- Good for small settings or flags (theme, token, etc.).

```javascript
localStorage.setItem("token", "abc123");
const token = localStorage.getItem("token");
```

- Not suitable for storing large data or binary files.

## Use Case Summary

| Use Case | Recommended Storage |
| --- | --- |
| User settings, theme, token | `localStorage` |
| Large datasets (e.g., messages, images) | `IndexedDB` |
| Offline-first apps (PWA, sync cache) | `IndexedDB` |
| Legacy apps using SQL | `WebSQL` (avoid now) |
| Saving files/blobs | `IndexedDB` |

## Conclusion

> **Use** `IndexedDB` **for anything beyond simple string values.**

It is:

- Modern
- Asynchronous
- Structured
- Efficient
- Fully supported


---

Original Source: https://www.mindstick.com/interview/34317/how-does-indexeddb-compare-to-websql-and-localstorage

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