Encode and decode Base64
Paste text to encode it as Base64, or paste a Base64 string to decode it back to plain text.
Settings
Choose encode or decode mode.
Base64 output
Output will appear here.
Why this tool exists
Vultio Base64 Encoder / Decoder converts plain text to Base64 format or decodes Base64 strings back to readable text, entirely within your browser.
Base64 encoding is widely used in web development, API design, and data transfer: embedding images as data URIs, encoding credentials in HTTP Basic Auth headers, and serializing binary content in JSON payloads.
Common use cases
- Encode API tokens or credentials for use in HTTP Authorization headers.
- Decode Base64-encoded JWT payloads to inspect their content during debugging.
- Convert text data to Base64 for safe embedding in JSON, XML, or HTML attributes.
- Quickly verify that a Base64 string decodes to the expected content.
- Prepare data URIs for embedding small images or icons directly in CSS or HTML.
Example input / output
Encode plain text
Input
Output
Encode credentials for HTTP Basic Auth
Input
Output
Decode a Base64 JWT payload segment
Input
Output
Common errors
Error: input is not valid Base64.
Cause: The string contains characters outside the Base64 alphabet (A–Z, a–z, 0–9, +, /, =), or padding characters (=) appear in the wrong position.
Fix: Make sure you copied the full Base64 string without extra spaces, newlines, or truncation. Switch to Encode mode if you meant to encode plain text.
Error: input contains characters that cannot be encoded.
Cause: Rare edge case where the internal URI encoding step fails on certain control characters.
Fix: Remove non-printable control characters from the input and try again.
Output looks correct but has unexpected padding.
Cause: Base64 strings are always padded with = characters to reach a multiple of 4. This is normal and not an error.
Fix: No action needed. The padding is part of the standard format.
Related guides
A practical guide covering when and why to use Base64 encoding in APIs, HTML, emails, and more.
A step-by-step checklist for generating and managing API keys, passwords, and JWT secrets safely.
Related tools
Encode or decode URL components and full URLs directly in the browser.
Generate passwords, API keys, and JWT secrets.
Format raw JSON to make it easier to inspect.
Frequently asked questions
What is Base64?
Base64 is an encoding scheme that represents binary data as printable ASCII characters. It is commonly used in data URIs, email attachments, and API payloads.
Is Base64 encryption?
No. Base64 is encoding, not encryption. It changes how data is represented, not how it is protected. Anyone with the Base64 string can decode it.
Does Base64 encoding send data to a server?
No. This tool runs entirely in your browser. No data is transmitted anywhere.
When is Base64 encoding useful?
It is useful when embedding binary data in text-based formats like JSON, XML, HTML, or HTTP headers, where raw binary would be unsafe or unsupported.