Developer & data utilities
Base64 Encoder / Decoder
Encode and decode text, URLs, and files to and from Base64 format.
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The Base64 Encoder/Decoder converts plain text, binary data, or URLs to and from Base64 format — an encoding scheme that converts arbitrary bytes to a set of 64 printable ASCII characters. Base64 is ubiquitous in web development: JWT tokens are Base64-encoded, email attachments use MIME Base64, data URIs embed images as Base64, and HTTP Basic Auth credentials are Base64-encoded.
Encoding is not encryption — Base64-encoded data can be trivially decoded by anyone. It is a representation format to safely transmit binary data over text-based channels that cannot handle raw bytes. For example, embedding a PNG image directly in HTML using a data URI, or including binary data in a JSON payload, requires Base64 encoding to prevent corruption.
Our tool handles UTF-8 text correctly, including multilingual content with Devanagari, Tamil, Chinese, and other Unicode characters. The URL-safe Base64 variant uses `-` and `_` instead of `+` and `/` to avoid conflicts in query strings and file paths — commonly used in JWT tokens and OAuth flows. All processing is local in your browser.
How to use this utility
- Use the controls below—paste text, pick files, or adjust options as described on the tool.
- Click the main action button. Processing runs in your browser on this device.
- Download or copy the output. Check the processing note for any external services used by this operation.
Common use cases
- Decoding JWT token payloads to inspect claims and expiry
- Creating data URIs for embedding images directly in HTML/CSS
- Encoding API credentials for HTTP Basic Authentication headers
- Inspecting Base64-encoded email attachments in MIME messages
- Encoding configuration files or secrets for inclusion in environment variables
Tips for best results
- 1Never confuse Base64 encoding with encryption — it provides zero security
- 2URL-safe Base64 replaces + with - and / with _ and is required in JWT tokens
- 3Base64 increases data size by ~33% — avoid for large files in production APIs
- 4Add padding = characters if decoding fails — some implementations omit them
- 5JSON Web Tokens (JWT) are three Base64url-encoded parts separated by dots
Frequently asked questions
- Is Konnect2Tools free?
- Yes. These in-browser tools are completely free to use with no account required for core functionality.
- Do my files leave my device?
- Browser document operations run locally, except where the operation uses an external service, such as AI summarisation. Read the processing note before using sensitive inputs.
- Is the Base64 Encoder / Decoder tool safe to use?
- Local operations process document content on your device. External-service operations may send inputs as described in the processing note. Keep originals and inspect the output.
- Is Base64 encoding secure?
- No. Base64 is an encoding format, not encryption. Anyone can decode a Base64 string instantly without any key. For security, use proper encryption (AES-256) or hashing (SHA-256). Base64 is only for safe representation of binary data in text contexts.
- Why does Base64 end with = or ==?
- Base64 encodes 3 bytes into 4 characters. If the input length is not a multiple of 3, padding characters (=) are added to make it so. One = means the input had one extra byte; == means two. Some implementations omit padding, which is why you might get errors when decoding — try adding = characters.
- What is the difference between standard and URL-safe Base64?
- Standard Base64 uses + and / characters which have special meaning in URLs. URL-safe Base64 replaces + with - and / with _ so the string can be safely included in URLs and HTTP headers without percent-encoding. JWT tokens use URL-safe Base64.
- Can I encode files (images, PDFs) to Base64?
- Yes — for text files, this tool works directly. For binary files (images, PDFs), you would typically read the file as binary and encode. Data URIs in HTML (e.g., for small icons) are created by encoding the image bytes in Base64 and embedding as src='data:image/png;base64,<encoded_data>'.
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