Download of Encode64 1.0 for Mac was available from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The actual developer of this free software for Mac is Adrian Hoe. The software lies within Developer Tools, more precisely Debugging Tools. We recommend checking the downloaded files with any free antivirus.
From the developer:
Encode64 is a handy tiny OS X utility app for software developers to quickly base64- encode/decode any text-based http payload for testing their REST APIs. The application is very easy to use, all you need to do is to copy your HTTP text into the app and push encode or decode.
You may want to check out more software for Mac, such as eclipse-php, Prototypes or KBSwitch, which might be similar to Encode64.