# Fairing
> “How did you hear about us?” (HDYHAU) surveys for Shopify and e-commerce brands, shown right after checkout. Customer survey responses are matched to their orders, so revenue can be broken down by the channel customers name. Native Shopify app, or a tracking script for any other site. Free up to 200 orders a month; paid plans from $49/month.
## Products
- [Attribution surveys](https://fairing.co/product/attribution-surveys)
- [Advanced Attribution](https://fairing.co/product/advanced-attribution)
- [NPS](https://fairing.co/product/nps)
- [Pricing](https://fairing.co/pricing)
- [Shopify App Store listing](https://apps.shopify.com/fairing)
- [Book a demo](https://fairing.co/demo)
## Guides
- [Best post-purchase survey apps for Shopify](https://fairing.co/resources/best-post-purchase-survey-apps)
- [HDYHAU attribution survey guide](https://fairing.co/resources/guides/hdyhau-attribution-survey-best-practices-guide)
- [What is a post-purchase survey?](https://fairing.co/resources/measurement-faqs/what-is-a-post-purchase-survey)
## Docs
- [Developer docs](https://docs.fairing.co/docs)
- [Tracking script (Web SDK)](https://docs.fairing.co/docs/sdk)