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Sync settings

Choose what your account keeps in step on every device where you are signed in.

  • My tools

    Always synced: the tools on your board, their order and size.

  • The windows open on your start page, including what you typed in them.

  • Every note in the notepad – on the notepad page, on your board and in windows.

  • Every list of website shortcuts – on the shortcuts page, on your board and in windows.

  • Every grid in the cover grid maker – on its page, on your board and in windows.

  • Every list of bookmarked organisations in the OIN lookup – on its page, on your board and in windows.

  • Keeps your pipeline and saved recipes on all your devices. Your files are never synced – only the steps and settings.

Turning something off removes it from your account straight away. Your devices keep their own copy.

Notifications

Tools that can tell you about something new while a Synsi tab is open, even when you are in another tab or app. Choose them for this browser.

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Notifications are blocked for this site. Allow them in your browser’s site settings (the icon left of the address), then switch them on here.

  • Says “New message” while a Synsi tab is open – never who wrote it or what.

Your choice is stored in this browser only. Notifications never show personal content such as a message or a number. They work while a Synsi tab is open; closed tabs get none.

Browse all tools →

Base64 Encoder and Decoder

Encode text to Base64 or decode Base64 back to readable text, with full UTF-8 and URL-safe support.

My tools →
Runs in your browser – your data never leaves your device Also available via our free API

How to use the Base64 Encode & Decode

  1. 1 Choose Encode or Decode.
  2. 2 Paste your text or Base64 string; enable URL-safe for Base64URL.
  3. 3 Copy the result.

What is Base64?

Base64 is a way to represent binary data using only 64 safe ASCII characters: A–Z, a–z, 0–9, + and /, with = as padding. It is used wherever binary data has to travel through systems designed for text, such as email attachments (MIME), data URIs in HTML and CSS, HTTP Basic authentication headers and JSON payloads.

Base64 is encoding, not encryption. Anyone can decode it, so never use it to hide passwords or secrets.

UTF-8 support

Text is converted to UTF-8 bytes before encoding, so accented letters, non-Latin scripts and emoji round-trip correctly: héllo encodes to aMOpbGxv. When decoding, the tool checks that the result is valid UTF-8 text and tells you if the input is not.

URL-safe Base64 (Base64URL)

Standard Base64 uses + and /, which have special meanings in URLs. Base64URL replaces them with - and _ and usually drops the = padding. It is used in JSON Web Tokens (JWT), OAuth and many APIs. The decoder accepts both variants and missing padding automatically.

Size overhead

Base64 output is about 33% larger than the input, because every 3 bytes become 4 characters. Keep that in mind when embedding images as data URIs.

Use it in your code

The same encoder is available through our free API, so you can encode and decode in scripts and pipelines without extra libraries.

Frequently asked questions

Is Base64 secure?

No. Base64 is only an encoding and can be decoded by anyone. Use real encryption to protect sensitive data.

Why does my decoded text look garbled?

The Base64 data probably represents binary content (such as an image) or text in a different character encoding than UTF-8. This tool decodes to UTF-8 text only.

How do I decode a JWT?

A JWT consists of three Base64URL parts separated by dots. Paste the first or second part (header or payload) into the decoder to read its JSON content.

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