Base64 Encoding

You can provide image data to the Vision API by specifying the URI path to the image, or by sending the image data as base64-encoded text.

Most development environments contain a native "base64" utility to encode a binary image into ASCII text data. To encode an image file:


    base64 input.jpg > output.txt


    base64 -i input.jpg -o output.txt


    C:> Base64.exe -e input.jpg > output.txt


    [Convert]::ToBase64String([IO.File]::ReadAllBytes("./input.jpg")) > output.txt

You can then use this output image data natively within the JSON request:

        "content": "BASE64_ENCODED_DATA"
      "features": [

Each programming language has its own way of base64 encoding image files:


In Python, you can base64-encode image files as follows:

# Import the base64 encoding library.
import base64

# Pass the image data to an encoding function.
def encode_image(image):
  image_content =
  return base64.b64encode(image_content)


In Node.js, you can base64-encode image files as follows:

// Read the file into memory.
var fs = require('fs');
var imageFile = fs.readFileSync('/path/to/file');

// Convert the image data to a Buffer and base64 encode it.
var encoded = Buffer.from(imageFile).toString('base64');


In Java, you can base64-encode image files as follows:

// Import the Base64 encoding library.
import org.apache.commons.codec.binary.Base64;

// Encode the image.
byte[] imageData = Base64.encodeBase64(imageFile.getBytes());


In Go, you can base64-encode image files as follows:

   import (

   // Open image file.
   f, _ := os.Open("image.jpg")

   // Read entire image into byte slice.
   reader := bufio.NewReader(f)
   content, _ := ioutil.ReadAll(reader)

   // Encode image as base64.