# API Reference

<table><thead><tr><th>Prop name</th><th width="239">Prop type</th><th width="182">Default value</th><th>Information</th></tr></thead><tbody><tr><td><code>subgraphApiKey</code></td><td><code>string</code></td><td>*required*</td><td>Please refer to this <a href="https://docs.teller.org/teller-widget/generating-subgraph-studio-api-key">guide</a> for generating an api key</td></tr><tr><td><code>buttonLabel</code></td><td><code>string</code></td><td><code>Cash advance</code></td><td>Label to display on the widget button</td></tr><tr><td><code>whitelistedTokens</code></td><td><code>{ [chainId: number]: string[] }</code></td><td><code>undefined</code></td><td>By default, Tokens to show additionally to the one in the user's wallet. If paired with <code>showOnlyWhitelistedTokens</code> these are the only displayed tokens</td></tr><tr><td><code>showOnlyWhitelistedTokens</code></td><td><code>boolean</code></td><td><code>false</code></td><td>Toggle to show only the tokens defined in <code>whitelistedTokens</code></td></tr><tr><td><code>buttonClassName</code></td><td><code>string</code></td><td><code>undefined</code></td><td>A css class name to pass to the button</td></tr><tr><td><code>isBareButton</code></td><td><code>boolean</code></td><td><code>false</code></td><td>An additional styling prop to remove all styles to the button</td></tr><tr><td><code>whitelistedChains</code></td><td><code>array</code></td><td><code>undefined</code></td><td>An array of chain ids to show in the chain dropdown.  <br>Available values :<br><code>1,137, 42161, 8453</code></td></tr><tr><td><code>referralFee</code></td><td><code>number</code></td><td><code>0</code></td><td><p>Referral fee %, in basis points. Ie <code>100</code> = 1%. </p><p></p><p>Max <code>500</code> = 5%.</p></td></tr><tr><td><code>referralAddress</code></td><td><code>string</code></td><td><code>0x193C83873843CA7a170490d3752BCcB678365d57</code></td><td>Recipient wallet address to receive referral fee.</td></tr><tr><td><code>welcomeScreenLogo</code></td><td><code>string</code></td><td><code>undefined</code></td><td>Logo (as URL) displayed on the widget's welcome screen. Image types .png, .jpg, .jpeg, .svg.</td></tr><tr><td><code>welcomeScreenTitle</code></td><td><code>string</code></td><td><code>undefined</code></td><td>Bold, header text on the widget's welcome screen.</td></tr><tr><td><code>welcomeScreenParagraph</code></td><td><code>string</code></td><td><code>undefined</code></td><td>Body, paragraph text on the widget's welcome screen.</td></tr></tbody></table>