# Site Performance Intelligems is designed to have as minimal an effect on site performance as possible. We use tools like [pagespeed.web.dev](https://pagespeed.web.dev/) (Lighthouse) and [webpagetest.org](https://www.webpagetest.org/) to ensure our script runs efficiently. Our goal is to create a seamless customer experience, preventing annoyances like flashing or flickering of elements on the page. Every website is designed differently, has different underlying tools, and different ways of loading. We have a wide range of configurations to help provide the fastest experience. This guide should help maximize them. ## Debugging Performance Issues ### Javascript Tag The default javascript tag looks like this: {% code fullWidth="true" %} ```javascript ``` {% endcode %} * `type="module"` – This leverages a newer Javascript paradigm called ESM and natively provides speed benefits. **This cannot be changed.** * `fetchpriority="high"` – This indicates to the browser to load Intelligems quickly so that our experiences are available as soon as the page is rendered. * `src=""` – This is a reference to your customer-specific site. Make sure to copy from your [settings page](https://app.intelligems.io/settings); the unique customer ID in the code block above is just an example. * `async` – This tells the browser to continue to render the page while Intelligems loads and is a best practice for high-performing sites. If you notice this is missing, please add it! ### Types of tests Different tests leverage different browser capabilities to execute and have different impacts on site speed. * **Javascript & CSS Injection:** These tests are some of the most efficient. We leverage the browser capabilities and simply add `