Base64 Decoder

Decode Base64 (standard or URL-safe) to UTF-8 text. Invalid input is detected with clear messages.

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Introduction

A Base64 Decoder is an online tool that converts Base64-encoded data back into its original readable form. Whether you're decoding plain text, JSON payloads, HTML, URLs, API responses, or other encoded content, this tool makes the process quick and effortless. Base64 encoding is widely used in web development, email systems, REST APIs, authentication, and data transmission to safely represent binary data as text.

This Base64 Decoder works entirely in your browser, so your encoded data is decoded locally without being uploaded to external servers. Whether you're debugging an application, inspecting API requests, decoding JWT payloads, or recovering encoded text, you can obtain the original content instantly while maintaining your privacy.

How it works

Paste your Base64-encoded string into the decoder, and it automatically converts the encoded characters back into their original representation. The tool follows the standard Base64 decoding algorithm defined in RFC 4648, correctly interpreting encoded data while preserving the original content whenever the input is valid.

All decoding takes place locally inside your web browser, making the process both fast and secure. No encoded strings or decoded results are transmitted to remote servers, allowing you to safely decode sensitive application data, configuration files, API payloads, and debugging information.

Common use cases

Developers commonly decode Base64 strings when debugging REST APIs, inspecting JSON Web Tokens (JWTs), reading encoded configuration values, analyzing email attachments, recovering embedded images, decoding authentication headers, and troubleshooting web applications. Students and IT professionals also use Base64 decoding to better understand how encoded data is exchanged between systems.

You can pair this tool with the Base64 Encoder to encode data again after editing, use the JSON Formatter to beautify decoded JSON responses, or combine it with the URL Decoder when working with encoded API parameters.

Benefits

This Base64 Decoder is completely free, requires no registration, and works instantly in any modern browser. Since all decoding happens on your device, your data remains private while you enjoy fast, accurate decoding of Base64 text, JSON, HTML, XML, images, and other encoded content.

Tips for best results

Ensure your Base64 string is complete before decoding. Missing characters, accidental line breaks, or extra spaces may cause decoding errors or produce incomplete output. If necessary, remove unnecessary whitespace before pasting the encoded data.

Remember that Base64 is an encoding format—not an encryption method. Anyone with a Base64 Decoder can recover the original content. Do not rely on Base64 to protect passwords, confidential information, or sensitive business data.

If the decoded result contains structured data such as JSON, XML, or HTML, consider opening it with the appropriate formatter for improved readability. This makes debugging APIs, configuration files, and application responses much easier.

Examples

Decode text

Input:
SGVsbG8gV29ybGQh

Output:
Hello World!

Decode JSON

Input:
eyJuYW1lIjoiSm9obiIsImFnZSI6MzB9

Output:
{"name":"John","age":30}

FAQ

What about URL-safe Base64?
Characters - and _ are converted to + and / automatically. Padding is fixed when missing.
Need to encode instead?
Use the Base64 Encoder.
Can you decode Base64?
Yes, you can. Use this tool to decode online by pasting the text into the input box and copying the decoded output.
How to convert Base64 encoding?
Using our free online tool right here. Drop your file or text and get an ASCII string output that you can easily copy and use.
Can you encode Base64?
Yes, you can encode text using our online tool. Just paste your text and get the encoded result.
How to encode text to Base64 online?
Use our online tool by pasting your text into the input box and copying the output. In a few seconds, you'll be effectively converting the characters to a web-safe format.
What is Base64?
It's an encoding scheme used to convert binary data into a text format that can be safely transmitted over the internet, using a combination of ASCII characters.
What is the difference between encoding and decoding?
Encoding converts binary data to Base64 text format, while decoding converts Base64 text back to its original binary format.

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