Question: I am deploying a **Flutter Web App** on **Firebase Hosting**.

And a **Flutter App on Android**.

To use App Links that redirect to my Android application, I need to verify the App Links serving the file `assetlinks.json` on the web at `https://example.com/.well-known/assetlinks.json`

How can I make the file available, without 3XX redirects, from my domain, that is Flutter deployed on the web with firebase hosting?

Answer: 
It is enough to add the `.well-know` folder and the file to the `web` folder of your Flutter project.

And to change the `firebase.json` adding headers and rewrites entries.

```
{
  "hosting": {
    "public": "build/web",
    "appAssociation": "NONE",
    "ignore": ["firebase.json", "**/.*", "**/node_modules/**"],
    "headers": [
      {
        "source": "/.well-known/assetlinks.json",
        "headers": [
          {
            "key": "Content-Type",
            "value": "application/json"
          }
        ]
      }
    ],
    "rewrites": [
      {
        "source": "/.well-known/assetlinks.json",
        "destination": "/.well-known/assetlinks.json"
      },
      {
        "source": "**",
        "destination": "/index.html"
      }
    ]
  }
}

```

build and deploy again and the file is now accessible!

Thanks for the easy guide to
<https://blog.bam.tech/developer-news/universal-links-firebase-hosting-and-flutter-web>
Firebase Hosting automatically generates `assetlinks.json` and `apple-app-site-association` files when they are requested. It doesn't require any extra configuration.

You just need to make sure that your app details (package, SHA256 certificate fingerprints, etc.) are correctly setup in the [Project Settings](https://console.firebase.google.com/project/_/settings/general) and make sure that in your `firebase.json` the property `appAssociation` is set to `"AUTO"` (or omitted, as `AUTO` is the default value).

Example `firebase.json`:

```
{
  "hosting": {
    "public": "build/web",
    "ignore": [
      "firebase.json",
      "**/.*",
      "**/node_modules/**"
    ],
    "appAssociation": "AUTO",
    "rewrites": [
      {
        "source": "**",
        "destination": "/index.html"
      }
    ]
  }
}

```

Ref: <https://firebase.google.com/docs/hosting/full-config#rewrite-dynamic-links>