# Base64 Encoder/Decoder - Complete Guide

> Encode and decode Base64 strings online. Learn how Base64 encoding works and when to use it.

Source: https://edesy.in/docs/tools/developer-tools/base64

Encode and decode Base64 strings with our free online tool.

## Introduction

Base64 encoding converts binary data to ASCII text format. It's used for:

- Embedding images in HTML/CSS
- Encoding data in URLs
- Email attachments (MIME)
- API data transfer
- Storing binary data in JSON

## How to Use

### Encoding

1. Go to [Base64 Encoder/Decoder](https://edesy.in/tools/base64)
2. Select **Encode** mode
3. Enter your text or data
4. Copy the Base64 output

### Decoding

1. Select **Decode** mode
2. Paste the Base64 string
3. View the decoded output

## How Base64 Works

Base64 uses 64 characters:

- A-Z (26 characters)
- a-z (26 characters)
- 0-9 (10 characters)
- + and / (2 characters)
- = for padding

Every 3 bytes of input become 4 Base64 characters.

## Common Use Cases

### Embedding Images

Convert small images to Base64 for inline CSS/HTML:

```css
.icon {
  background: url('data:image/png;base64,iVBORw0K...');
}
```

### API Authentication

Encode credentials for Basic Auth:

```javascript
const auth = btoa(`${username}:${password}`);
// Use in header: `Basic ${auth}`
```

### Data URLs

Include small files directly in web pages:

```html
<img src="data:image/png;base64,iVBORw0KGgo..." />
```

## Best Practices

### When to Use

- Small images (<10KB)
- Configuration data
- Simple authentication
- Embedding in JSON/XML

### When NOT to Use

- Large files (increases size by 33%)
- Performance-critical applications
- Files served separately
- Already compressed data

### Security Notes

- Base64 is NOT encryption
- Anyone can decode Base64
- Don't use for passwords alone
- Combine with actual encryption

## Related Tools

- [Image to Base64](https://edesy.in/tools/image-to-base64) - Convert images
- [URL Encoder](https://edesy.in/tools/url-encoder) - URL-safe encoding