# Checking the usability of your key

Your key may not be available at some times. For instance:

* Your key may have reached its daily cap set by you
* Your user has reached their individual usage cap for the day
* The balance on your key is exhausted

By default, Address Finder will not initialise if your key is not usable for whatever reason. You may use the [`onLoaded`](https://address-finder.ideal-postcodes.co.uk/interfaces/Controller.ControllerOptions.html#onLoaded) and [`onFailedCheck`](https://address-finder.ideal-postcodes.co.uk/interfaces/Controller.ControllerOptions.html#onFailedCheck) callbacks to make necessary adjustments.

To disable key checking, set `checkKey` to `false`.

Loading...

```
<form style="max-width: 450px; padding: 10px;">
<p id="message"></p>
<label for="input">Search Your Address</label>
<input type="text" id="input" placeholder="Start typing address here" />
<label for="first_line">Address First Line</label>
<input type="text" id="first_line" />
<label for="second_line">Address Second Line</label>
<input type="text" id="second_line" />
<label for="third_line">Address Third Line</label>
<input type="text" id="third_line" />
<label for="post_town">Town or City</label>
<input type="text" id="post_town" />
<label for="postcode">Postcode</label>
<input type="text" id="postcode" />
</form>
```

```

import { AddressFinder } from "@ideal-postcodes/address-finder";

AddressFinder.setup({
inputField: "#input",

  // Test key: 'ak_test' passes the check
  apiKey: "ak_test",
  // Test key: 'ak_fails' fails the key check
  // apiKey: 'ak_fails',

  // By default, checkKey is enabled
  checkKey: true,

  // Invoked if plugin loads
  onLoaded: function () {
    document.getElementById("message").textContent =
      "Check passed!";
  },

  // Invoked if key fails check
  onFailedCheck: function () {
    document.getElementById("message").textContent =
      "Check failed. Please manually enter your address";
  },

  outputFields: {
    line_1: "#first_line",
    line_2: "#second_line",
    line_3: "#third_line",
    post_town: "#post_town",
    postcode: "#postcode",
  },

});
```