What is HEY Email Privacy Proxy?
When a HEY user views an email that contains an external image, 37signals can fetch that image through the HEY Email Privacy Proxy. The image host sees HEY's request instead of the reader's IP address, which prevents the host from learning the reader's network location or directly tying the fetch to that person's device.
HEY's image-proxy documentation says the service requests only image URLs referenced in viewed emails. It does not crawl websites, follow page links, execute scripts, or index content. It caches successful responses, follows redirects to the final image, honors HTTP cache headers, and rejects responses that are not image content.
The full recorded user agent starts hey.com/imageproxy, while this directory uses the broader stable token hey.com. Cloudflare does not mark the client as following robots.txt, and the bot metadata leaves compliance unknown. The record also has no verified IP status or signature-agent URL. A matching header identifies the claimed proxy but should not grant access to private image URLs.
This proxy protects email privacy; it is not an AI crawler. Its requests do not improve AI search visibility, create citations, or supply a documented training dataset. They also should not be treated as ordinary email-open analytics because the recipient's address is hidden and cached images can serve later views without another origin request.
