You can use a web pixel app extension to collect behavioral data for marketing campaign optimization and analytics. This guide provides the reference documentation for the web pixel app extension. ## Reference documentation <div class="resource-card-grid"> <div> <a class="resource-card" href="/docs/api/web-pixels-api" data-theme-mode=""> <div class="resource-card__indicator-container"><img src="/assets/resource-cards/hearts" data-alt-src="/assets/resource-cards/hearts-dark" aria-hidden="true" class="resource-card__icon themed-image"></div> <h3 class="resource-card__title"> Web pixel extension API </h3> <p class="resource-card__description">Learn about the sandboxing modes for web pixels, and the API references that are available for the sandbox.</p> </a> </div> <div> <a class="resource-card" href="/docs/api/web-pixels-api/standard-events" data-theme-mode=""> <div class="resource-card__indicator-container"><img src="/assets/resource-cards/blocks" data-alt-src="/assets/resource-cards/blocks-dark" aria-hidden="true" class="resource-card__icon themed-image"></div> <h3 class="resource-card__title"> Standard Events Reference </h3> <p class="resource-card__description">Learn about the ways of tracking and sending events with web pixels.</p> </a> </div> </div> ## Next steps - Learn how you can [use web pixels](/docs/apps/build/marketing-analytics/pixels) on an online store to collect behavioral data for marketing campaign optimization and analytics. - [Create a web pixel app extension](/docs/apps/build/marketing-analytics/build-web-pixels) and subscribe to all events emitted by Shopify.