How to Encode and Decode Base64 in JavaScript (Complete Guide)

Introduction

Base64 encoding is essential in JavaScript development for handling binary data.

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Encoding in JavaScript

const encoded = btoa("Hello World");
console.log(encoded);

Decoding in JavaScript

const decoded = atob(encoded);
console.log(decoded);

Handling Unicode

const encoded = btoa(unescape(encodeURIComponent("Hello 🌍")));

Use Cases

• API authentication
• Image embedding
• Data transfer

Common Mistakes

• Using btoa on Unicode directly
• Double encoding

Best Practices

• Always validate input
• Use UTF-8 conversion

FAQs

Can Base64 store images?

Yes, as data URLs.

Is Base64 efficient?

It increases size by ~33%.

Conclusion

JavaScript makes Base64 easy with built-in functions. Use proper encoding techniques for reliable results.