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Free Base64 Encoder & Decoder Online

Encode strings, files, or secrets into Base64 and decode them back on the fly—everything happens in your browser.

Updated Dec 06, 2025

Text
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Base64
SGVsbG8gV29ybGQh

Encoding basics

Encode and decode Base64 safely

Base64 is a reversible way to represent binary data with ASCII characters. Use it to embed assets in HTML, move files through JSON APIs, or sanitize payloads that travel through systems allergic to raw bytes. This tool handles both encoding and decoding entirely inside your browser.

Understand the workflow

Drag files, paste strings, or type secrets directly into the editor. The Base64 encoder converts every byte into a radar-friendly alphabet without altering the underlying information. Toggle line wrapping or URL-safe output when preparing data for query strings and OAuth state parameters.

Decoding works the same way: paste a Base64 string and preview the original text or binary asset instantly. Helpful warnings appear when padding is missing or characters fall outside the expected alphabet, reducing the chance of silent corruption.

  • Streaming support

    Large inputs are chunked efficiently so multi-megabyte payloads do not freeze your tab.

  • Clipboard shortcuts

    Copy either representation with a single click, making it easy to move between terminals, IDEs, and issue trackers.

Know when to reach for Base64

Developers use Base64 to embed small inline images, transport certificates, or send zipped files through APIs that only accept text. It is not encryption; it is simply a reliable translation. The encoder clarifies this distinction so you know when a stronger cryptographic primitive is required.

Because everything runs locally, you can inspect JWT segments, webhook payloads, or proprietary documents without exposing them to remote services. Pair the results with other FreeTools.run utilities to chain multiple transformations without leaving your browser.

  • Data URI helpers

    Wrap output with `data:` prefixes to embed assets into CSS or HTML prototypes.

  • Validation hints

    Helpful badges remind you when Base64 is being used for obfuscation versus safe transport so security reviews stay honest.

Common scenarios

Email attachments

Convert binaries before sending them through systems that still rely on MIME Base64 transfer encoding.

CLI tooling

Preview values produced by `base64` shell commands and ensure flags (`-w0`, `-d`) match expectations.

OAuth debugging

Decode state parameters or proofs generated by SDKs to verify that claims were assembled correctly.

Infrastructure templates

Embed small scripts into Terraform or CloudFormation templates without corrupting whitespace.

Next step

Need to inspect token claims?

Hop over to the JWT Decoder to split tokens into header, payload, and signature segments with the same privacy guarantees.

Open JWT Decoder

Popular combinations

Frequently asked questions

What is Base64 encoding?

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It is commonly used to encode data that needs to be stored and transferred over media that are designed to deal with textual data.

Is Base64 encryption?

No. Base64 is an encoding scheme, not encryption. It does not secure your data; it simply changes its representation. Anyone can decode Base64 back to the original data without a key.

Can I encode images?

Yes. You can convert images to Base64 strings, which can then be embedded directly into HTML or CSS files using Data URIs, reducing the number of HTTP requests.

Is my data safe?

Yes. All encoding and decoding happen locally in your browser. We do not transmit your data to any server.

How to use Free Base64 Encoder & Decoder Online

Follow these four quick steps to securely encode or decode payloads right inside your browser—no downloads, no accounts, and no data leaving the FreeTools.run sandbox.

  1. Step 1: Load your source data

    Paste text, drag a file, or start with our curated sample to understand how the encoder workflow behaves with real inputs.

  2. Step 2: Adjust tool options

    Toggle presets, update formatting rules, or choose export preferences. All controls update in real time so you can preview the effect before committing.

  3. Step 3: Review the live preview

    Use the split-pane preview, inline validation, or diff output to confirm the transformation looks correct before you copy anything back into your project.

  4. Step 4: Export or chain another tool

    Copy the result, download a file, or jump into a related FreeTools.run utility (like Diff Checker or the QR Code Generator) to continue the workflow without leaving the browser.

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