paypal checkout components

Javascript Integration for PayPal Button and PayPal Checkout


PayPal Checkout

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npm version
apache license

A set of components allowing easy integration of PayPal Buttons and PayPal Checkout into your site, powered by

Dev Docs



Please submit any issues about the JS SDK here:


Please feel free to follow the Contribution Guidelines to contribute to this repository. PRs are welcome, but for major changes please raise an issue first.

Quick Setup

Set up your env:

npm install

Run tests:

npm test

Run in dev mode:

npm run dev

Testing Tasks

npm test

Runs all testing tasks lint, flow, karma, jest-ssr, jest-screenshot, & check-size.

Flags Description
–clear-cache Clear Babel Loader and PhantomJS cache
–debug Debug mode. PhantomJS, Karma, and CheckoutJS
–quick Fastest testing. Minimal output, no coverage
–browser Choose Browser



npm run lint

npm run lint -- --fix
# attempt to automatically fix any problems

Runs eslint using definitions extended from Grumbler-Scripts.


npm run flow

Checks for typing issues using Flow. Prior to running this task, flow-typed should be run to generate type interfaces for the various 3rd-party libraries we use.


npm run karma

npm run karma -- --keep-open
# keeps the test browser window open to allow debugging
npm run karma -- --capture-console
# dumps the browser's console output into the terminal

Runs Karma tests using the Mocha framework. Responsible for running the test/e2e & test/integration directories.


npm run jest-ssr

Checks for the correct rendering of components on the server-side using Jest.


npm run jest-screenshot

Uses Puppeteer & Jest to take screenshots and checks against existing views to look for discrepancies. Tests are defined in test/screenshot/config.js.


npm run check-size

Checks to make sure that the compiled & gzipped bundle doesn’t exceed the recommended size limit.


This package is published weekly, Every Wednesday. Please view our Changelog to stay updated with bug fixes and new features.

Logo Strategy with paypal-sdk-logos

Our usage of svg logos is optimized for performance. Here’s how it works for the two-phased render for the Buttons component:

  • First Render - Buttons are first rendered on the client-side inside an <iframe> tag using the code bundled inside the JS SDK script. This <iframe> tag has no src attribute at this point in the rendering life cycle. We leverage the __WEB__ global variable to determine if we are rendering client-side or server-side. The __WEB__ global variable will equal true when rendering client-side. To minimize the bundle size of the JS SDK script, we load these svg logos from the CDN as external images (ex: <PayPalLogoExternalImage />).

  • Second Render - The second phase of rendering happens on the server-side. This <iframe> tag is fully rendered by setting the src attribute and making an http request to the server to populate the contents which are securely hosted by PayPal’s servers on The same code in this repo is used to render the buttons on the server-side. To ensure there are no issues with the logos, we have decided to inline the svg code for this server-side render (ex: <PayPalLogoInlineSVG />). The __WEB__ global variable is set to false to control what code executes during the server render.