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KERN uses Cloudinary to store and serve user profile avatars. Images are uploaded directly from the Android app to Cloudinary, which returns a public HTTPS URL. That URL is then stored in the KERN API, which never handles raw image data itself.

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Why Cloudinary

Cloudinary serves images through a global CDN, applies automatic format optimization, and removes the need for file storage on the backend server. This keeps the KERN API stateless and fast.

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Upload flow

1

User selects a photo

The user taps their avatar on the profile screen. Android’s photo picker opens, allowing them to choose an image from their gallery.
2

App uploads to Cloudinary

The Android app uses the Cloudinary MediaManager to upload the image binary directly to Cloudinary. The upload is handled asynchronously — the API server is not involved at this stage.
MediaManager.get()
    .upload(imageUri)
    .unsigned(BuildConfig.CLOUDINARY_UPLOAD_PRESET)
    .callback(uploadCallback)
    .dispatch();
3

Cloudinary returns a URL

On success, Cloudinary returns a public HTTPS URL of the form:
https://res.cloudinary.com/<cloud_name>/image/upload/<public_id>.jpg
4

URL is sent to the KERN API

The app sends the URL to the KERN API using the avatar update endpoint:
curl -X PUT https://your-kern-api.vercel.app/users/avatar \
  -H "Authorization: Bearer <token>" \
  -H "Content-Type: application/json" \
  -d '{"avatar_url": "https://res.cloudinary.com/..."}'
The URL is stored in the avatar_url column of the users table.
5

Glide loads the avatar

Throughout the app, Glide loads the avatar from the stored Cloudinary URL:
Glide.with(context)
    .load(user.getAvatarUrl())
    .circleCrop()
    .into(imageView);

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Setup

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1. Create a Cloudinary account

Sign in at cloudinary.com and create a free account. Note your Cloud Name, API Key, and API Secret from the dashboard.

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2. Create an upload preset

In the Cloudinary dashboard, go to Settings → Upload → Upload presets and create an unsigned preset. This allows the Android app to upload without exposing your API secret.

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3. Add credentials to local.properties

Add the following to local.properties in the Android project root. This file is excluded from version control.
local.properties
CLOUDINARY_CLOUD_NAME=your_cloud_name
CLOUDINARY_API_KEY=your_api_key
CLOUDINARY_UPLOAD_PRESET=your_unsigned_preset_name
These are injected into the build as BuildConfig fields via build.gradle.kts:
build.gradle.kts
buildConfigField("String", "CLOUDINARY_CLOUD_NAME",
    "\"${localProperties.getProperty("CLOUDINARY_CLOUD_NAME")}\"")
buildConfigField("String", "CLOUDINARY_API_KEY",
    "\"${localProperties.getProperty("CLOUDINARY_API_KEY")}\"")
buildConfigField("String", "CLOUDINARY_UPLOAD_PRESET",
    "\"${localProperties.getProperty("CLOUDINARY_UPLOAD_PRESET")}\"")

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4. Initialize MediaManager

Initialize the Cloudinary MediaManager in your Application class or the activity that handles avatar selection: 
Map<String, Object> config = new HashMap<>();
config.put("cloud_name", BuildConfig.CLOUDINARY_CLOUD_NAME);
config.put("api_key", BuildConfig.CLOUDINARY_API_KEY);
MediaManager.init(this, config);

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Dependency

The Cloudinary Android SDK is declared in app/build.gradle.kts: 
implementation("com.cloudinary:cloudinary-android:2.2.0")

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Using a different image host

The avatar_url field in the KERN API accepts any valid HTTPS URL. If you deploy your own instance of KERN and prefer a different storage solution — such as AWS S3, Imgix, or your own CDN — you can send any HTTPS image URL to PUT /users/avatar and Glide will load it the same way.
The URL must be publicly accessible over HTTPS. Private or signed URLs that expire will cause broken avatar images after the signature expires.

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