Base64 Encoding Explained: What It Is and When to Use It

If you've ever seen a long string of letters and numbers embedded in a URL, an email attachment, or an API request, there's a good chance it was Base64 encoded.

What is Base64 encoding?

Base64 is a method for converting binary data — like images, files, or arbitrary bytes — into a text format made up of only letters, numbers, and a few symbols. This makes it safe to embed binary data inside text-based formats like JSON, XML, HTML, or email, which weren't designed to handle raw binary content.

Common use cases for Base64

• Embedding small images directly inside HTML or CSS using data URIs.
• Encoding email attachments (this is part of how MIME email works).
• Sending binary data through APIs that only accept text fields, such as JSON payloads.
• Encoding authentication credentials in HTTP headers, such as Basic Auth.

Important: Base64 is not encryption

Base64 encoding is reversible by design — anyone can decode it instantly. It provides no security or confidentiality. Don't use it as a substitute for actual encryption when handling sensitive data.

How to encode text to Base64

1. Open the Base64 Encoder tool.
2. Paste your text.
3. Click encode and copy the result.

How to decode Base64 back to text

1. Open the Base64 Decoder tool.
2. Paste the Base64 string.
3. Click decode to see the original text.

Both tools run entirely in your browser, so nothing you encode or decode is sent to a server.

Related encoding tasks

If you're working with URLs specifically, you likely want URL Encoding or URL Decoding instead, which handle a different character set designed for safe use inside web addresses.