> For the complete documentation index, see [llms.txt](https://docs.emaildelivery.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.emaildelivery.com/docs/subscriber-opt-in-forms/sending-to-double-opt-in-contacts.md).
# 2⃣ Sending to double opt-in contacts
docs in progress