...While you may find a way to run it directly in a browser, we don't actively support or provide troubleshooting assistance with this scenario. We recommend setting up your own Node.js backend. Exposing your API keys in a frontend application is almost always a bad idea. Using the SDK is pretty straight-forward as you can see from the following examples. For more examples take a look in blockfrost-js-examples repository. Blockfrost Node.js SDK throws 2 types of errors, BlockfrostServerError and BlockfrostClientError. Each of these errors is extended from the built-in Error class, allowing you to properly catch it and handle it in your code.