[Free] Base 64 extension. File to/from Base 64

Base 64 extension.

With this extension we can:

  • Convert an image, sound, video, pdf file,... to a Base 64 string.

  • Convert a Base 64 string to file.

  • Convert the Picture of an Image component to Base 64.

  • Set a Base 64 string as Picture in an Image component.

  • Convert a Picture from a Canvas to a Base 64 string.

  • Take a Picture with the Camera and convert it to Base 64 string

  • Download a file from the internet and convert it to Base 64.

  • Convert a Uri to Path.

- Why convert a file to Base 64?

  • To save it to a TinyDB.
  • To upload a text string to the internet, instead of a file (for example by PHP).
  • To work directly with the image without previously converting it to a file (for example TakePicture with Cam and load it in Canvas directly.)
  • Draw on a Canvas and pass it directly to an Image component.

- Where can we download the updated extension?


- What blocks does the extension have?

  • I, @Juan_Antonio, as the author of this extension, allow any user to use it in their application for the MIT App Inventor Summer Appathon 2023.

1.- Image file in assets to Base 64. Base 64 to File in ASD. Show in Image2.

Base64_Simple.aia (487.9 KB)

2.- Interesting examples in this topic:

3.- More examples in this Community:


Hi Juan,
which is the correct path to read the files for the "File to String" component?
in other word I should get a file in this folder, but it can't find it: file:///storage/emulated/0/Pictures/
If I check the string of the component "When KIO4_Base64 Got String" says "File not found"...
I have Android 11, maybe it gives some problems?
can you help me?

Try this:

Base64_Simple_Picture.aia (488.5 KB)

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Thanks Juan,
but the problem is only in the path read by component "FileToString".
here my blocks:

The file exist as proved by the component FileExists and also the MimeType is correctly taken.
But only String doesn't work: the label Check_string says: "File not found"...

Check the code of my previous application.
Use "FileToStringASD"

what should I see in label 3 after button 4 is pushed?
in my phone using the AI Companion the label simply disappears... or is blank...

if I compile the app and use it, the 3rd label say false and correctly the last label says File not found....

Possibly it will be a problem with Android 11.

Try blocks
set absolute path (/storage/emulated/0/Android/data/'namepackage'/files/aaa.png)

set absolute path

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Thanks Juan_Antonio!!! now it works!
great job!

on android 11 How to convert xlsx file to string. xlsx file in in download folder and created by another application.

I have not tested directly with a file in Download on Android 11.
Try this, copy the file from Download to ASD (File component), pass it to base64 in the ASD directory.


Thanks it worked

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