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Base64 Encoder / Decoder

Encode plain text into Base64 or decode a Base64 string back into readable text. Supports standard and URL-safe Base64. Everything runs locally in your browser — nothing is ever sent to a server.

About this tool

Base64 is a way to represent binary or text data using only 64 printable ASCII characters, often used to safely embed data in text-based formats like JSON, HTML, CSS, or URLs. This tool converts between plain text and Base64 in both directions, with an optional URL-safe mode that swaps + and / for - and _ and removes = padding.

How to use

  1. Select the Encode or Decode tab.
  2. Enter your text (or a Base64 string in Decode mode) — the result updates as you type.
  3. Enable URL-safe mode if the result will be used in a URL, query parameter, or filename.
  4. Click Copy to copy the output to your clipboard.

When to use this tool

  • Embedding small binary data (images, fonts) as text inside CSS, JSON, or XML data URIs.
  • Inspecting or decoding a Base64-encoded value from an API response, JWT, or config file.
  • Producing a URL-safe Base64 string for use in a query parameter or filename.
  • Encoding HTTP Basic Authentication credentials before sending them in a header.

Frequently asked questions

What is Base64 encoding?

A way to represent binary or text data using 64 printable ASCII characters. Widely used in JSON, HTML, CSS, email, and API payloads.

Is Base64 the same as encryption?

No. Base64 only changes how data is represented — it does not hide it. Anyone can decode it without a password.

What does the URL-safe option do?

Replaces + with - and / with _, and removes = padding, so the result can be used in URLs without extra percent-encoding.

Why do I get an error when decoding?

The input is not valid Base64 — it may contain invalid characters, have an incorrect length, or use URL-safe encoding while the toggle is off (or vice versa).

Is my text sent to a server?

No. All processing runs in your browser. Nothing is transmitted.

Does this work offline?

Yes. Once the page has loaded, all processing runs locally.

What is Base64 used for in practice?

Data URIs in CSS, binary data in JSON payloads, HTTP Basic Auth headers, JWT token parts, and email attachments.

Is this tool free?

Yes, completely free with no sign-up required and no usage limits.

Everything is processed locally in your browser — the text is never sent to a server.