Hosted API - Returning annotated image in JavaScript

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  • Project Type: Object Detection
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I am trying to use the Hosted API to send an image from my React Native app and then receive the annotated image back. However, I am running into some issues with the response.

Here’s what I have:

const sendFrameToServer = async (base64Image: string) => {
      method: "POST",
      url: "xxxx",
      params: {
        api_key: "xxxx",
        labels: true,
        format: "image",
      data: base64Image,
      headers: {
        "Content-Type": "application/x-www-form-urlencoded",
      .then(function (response) {
        const blob = new Blob([], { type: "image/jpeg" });
        const imageUrl = URL.createObjectURL(blob);
      .catch(function (error) {

When I log the imageUrl I get this:

 WARN  Received data was not a string, or was not a recognised encoding.
 LOG  blob:337b3060-7593-4121-9367-6a60148f9bbc?offset=0&size=0

I am confused about how to actually use the returned image. I understand from the docs that it returns an image with annotated predictions as a binary blob with a Content-Type of image/jpeg, but I’m not sure how to actually use this image and display it.

I’m trying to use it like this:

 {image && (
              source={{ uri: image }}
                position: "absolute",
                top: 0,
                left: 0,
                width: "100%",
                height: "100%",
                zIndex: 1,

to no avail. What am I missing here? I just want to display the image.

As a follow up, is there a way I can get both the detections JSON and the image returned within the same call?

Hi @jansdhillon

As far as I’m aware, the API (when queried with format set to image) should return a base64 encoded image URI, not a binary blob. Could you double-check by treating the response as a base64 image and see if that resolves your issue?

As for your follow-up question on how to get the JSON and image returned in the same call, we do not currently support returning both the image and JSON in the same call. As an alternative, if you have a JSON, you could implement logic to “draw” JSON boxes onto your image.

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