Online Base64 Encoder and Decoder with Base64url and UTF-8 Text Support

• Encode to Base64

  Convert UTF-8 text, JSON, configuration snippets, and credentials into standard Base64 strings for API debugging, headers, and text transport.

• Decode from Base64

  Restore Base64 fields from logs, API responses, config files, queues, and cache entries into readable text for inspection.

• URL-safe variant

  Use the URL-safe Base64url variant that substitutes + and / with - and _ for use in query parameters and path segments.

• UTF-8 text handling

  Uses browser TextEncoder and TextDecoder APIs, so multilingual text, symbols, and JSON can be encoded safely without the classic btoa Unicode issue.

• Bidirectional swap

  Send output back to input to verify round trips or continue converting between standard Base64 and Base64url.

• Instant copy and clear

  Copy the result to your clipboard with one click, or clear both fields to start fresh.

1. 1

   Select Encode or Decode to set the conversion direction.

2. 2

   Type or paste your input into the text area.

3. 3

   The result updates in real time in the output area.

4. 4

   Use Copy to grab the output, or Use output as input to verify the reverse conversion.

5. 5

   Turn on URL-safe mode when the value belongs in a query string, path segment, or unpadded token.

• Use Encode when you need to prepare text for data URLs, email attachments, or storage in systems that expect Base64.
• Use Decode when you receive a Base64 string and need to inspect, edit, or use the original content.
• Use URL-safe mode when the encoded value will appear in a URL query parameter or URL path segment.
• Use the default UTF-8 text flow for multilingual text, JSON, URLs, and most API debugging cases.

• Data URLs in HTML and CSS

  Embed small images, fonts, or icons as Base64 data URLs to reduce HTTP requests in single-file pages and prototypes.

• API payload encoding

  Encode JSON blocks, configuration text, or serialized strings for text fields in REST, GraphQL, queue messages, and integration payloads.

• Authentication headers

  Encode credentials or token components for Basic Auth headers, OAuth flows, and signed request formats.

• Debugging and inspection

  Decode Base64 strings found in API logs, browser developer tools, or configuration files to inspect their original content.

• JWT and token troubleshooting

  Inspect Base64 segments in authentication tokens to verify expected header and payload structure during auth debugging.

• Queue and cache payload checks

  Decode Base64 fields stored in message queues, Redis, or database records to validate what was actually persisted.

If the Base64 result will be embedded in a query string or callback URL, use URL Encode & Decode next for percent-encoding. When debugging login state, Bearer tokens, or three-part tokens, open JWT Inspector to inspect header and payload data. For embedding image files in HTML, CSS, or JSON, use Image to Base64 ; when you already have an image Base64 string and need to preview or restore it, use Base64 to Image .

• Confirm the original payload is actually text. Images, archives, and audio may decode into non-printable bytes rather than readable content.
• Use URL-safe mode when the Base64 string will appear in URLs; standard Base64 can break certain URL parsers.
• Base64 adds roughly 33% overhead compared to the original binary size. For large payloads, consider compression or streaming.
• Do not use Base64 for encryption. Base64 is an encoding format, not a security mechanism.
• When decoding, remove any leading or trailing whitespace to avoid padding-related failures.
• For cross-language services, standardize on UTF-8 and document that encoding in your API contract.
• Treat Base64 as a transport format; keep original structured data and metadata where long-term traceability matters.

• Base64 is approximately 33% larger than the original binary data, which can affect storage and transfer costs for large payloads.
• This page encodes and decodes UTF-8 text. It does not provide ISO-8859-1, Windows-1252, GBK, or other character set switching.
• Very large files (hundreds of megabytes) may cause memory pressure in the browser. This page is designed for strings, configuration blocks, and moderate payloads.
• This page does not support direct file upload for Base64 conversion. If you need to encode a file, use a dedicated file-to-Base64 page.
• Base64 encoding does not provide data integrity guarantees like checksums or hashes.
• Auto-detection of URL-safe Base64 is pattern-based; for edge cases, manually confirm the intended variant.
• Decoded output readability depends on whether the source was text; binary payloads may decode to non-printable characters.