What is Base64 Encoder/Decoder?
Base64 is an encoding scheme that converts binary or text data into a ASCII string format using 64 characters (A-Z, a-z, 0-9, +, /). It is widely used in email (MIME), data URIs, JWT tokens, and API payloads to safely transmit data as text. Base64 is not encryption — anyone can decode it.
Best for
- API payload prep
- Encoded string inspection
- Inline data experiments
- Decoding JWT and data URI components
Privacy
Encoding and decoding happen in-browser, so temporary values and internal strings do not leave your device.
Quick tips
- Base64 is not encryption.
- Decode before editing, then encode again after changes.
- Use JSON Formatter after decoding JSON-like payloads.
How to use this tool
- Paste the text or Base64 string.
- Choose encode or decode.
- Copy the output once it validates.
Common questions
Is Base64 secure?
No. Base64 is an encoding format, not encryption. Anyone can decode it. Never use Base64 as a security measure.
Why use a client-side Base64 tool?
It keeps test strings, headers, and temporary payloads inside your browser. Nothing is sent to a server, which is important when working with sensitive or internal data.
Can Base64 encode binary files?
Base64 can encode binary data, but this tool focuses on text encoding and decoding. For file-based Base64 encoding, use a dedicated file converter.
How do I encode a URL in Base64?
Paste the URL text into the input field and select encode. The tool outputs the Base64 representation. For URL-safe encoding, you may need to replace + with - and / with _ manually.
What is Base64 used for?
Base64 is commonly used to encode data in URLs, email attachments (MIME), data URIs in HTML/CSS, JWT tokens, and API payloads where binary data needs to be transmitted as text.
Does Base64 increase file size?
Yes. Base64 encoding increases the data size by approximately 33% because every 3 bytes of input becomes 4 characters of output.