Base64 Text Encoder / Decoder

About Base64 Text Encoder / Decoder

Last updated: May 2026

OptiPix Base64 Text Encoder/Decoder converts between plain text and Base64 encoding directly in your browser. Encode any UTF-8 text to Base64, or decode Base64 strings back to readable text. Toggle URL-safe Base64 mode to use - and _ instead of + and / for URL and filename compatibility. Enable live mode for real-time conversion as you type. See input/output size stats showing the encoding overhead. Drop any file to encode its bytes to a Base64 string, or paste a Base64 string to decode and download as a file. This tool handles text and arbitrary files - for image-specific Base64 with preview and CSS output, see the Image to Base64 tool. All processing happens locally in your browser.

How It Works

The tool uses JavaScript's btoa() and atob() functions for ASCII-range text. For full UTF-8 support, it first encodes the text using TextEncoder, then converts the byte array to a Base64 string. URL-safe mode swaps + for - and / for _ in the output.

Use Cases

• •Encode API keys and tokens for configuration files
• •Decode Base64-encoded data from APIs and JWTs
• •Convert files to Base64 for embedding in JSON payloads
• •Prepare data for email MIME encoding
• •Debug Base64-encoded strings in web applications

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If you find Base64 Text Encoder / Decoder useful, check out these related tools: URL Encoder / Decoder, Text to Binary / Hex / Octal, and Hash Generator. All tools run entirely in your browser with no uploads or signups required.