# Set up a bump offer with Rebilly Instruments This topic describes how to set up a bump offer for use with the Rebilly Instruments JavaScript library. - The bump offer feature is in beta and active development. This means it may contain bugs and instability. - To use a bump offer, it must be used together with the `items` property. Important This topic assumes that you have already completed one of the [Get started guides](/docs/dev-docs/get-started-integrate-payments), and are looking to customize or extend the functionality. ## Bump offer setup The bump offer will be displayed at the top of the payment method information. Preview div iframe JavaScript ```js import RebillyInstruments from '@rebilly/instruments'; RebillyInstruments.mount({ organizationId: 'test-org-2019-12-07', publishableKey: 'pk_sandbox_WcUZLs3xwB7dubewna3zJA75wdMBEHeWHOyQww8', websiteId: 'example', apiMode: 'sandbox', items: [ { planId: 'rebilly-e-book', quantity: 1, }, ], bumpOffer: [ { planId: 'rebilly-t-shirt', quantity: 1, }, ], }); ``` HTML ```html

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