# Double opt-in

> How double opt-in works, why it is the proof that counts in a dispute — and why it does not apply to contact form enquiries.

Synonyms: double opt in, confirmed opt-in, confirmation email, verified subscription

The reason is simple: without confirmation anyone can enter somebody else's address. The second step proves that the owner of the address agreed — and in a dispute that proof is exactly what counts.

In practice: sign-up, immediate confirmation email, one click, done. Whoever does not click stays out. A proper implementation also records the time and origin of the confirmation and sets up the unsubscribe path at the same time.

One distinction matters: the procedure applies to the newsletter list. An enquiry through a contact form is something else — you answer that, you do not add it to a marketing list.

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Source: https://btlabs.dev/en/glossary/double-opt-in
Last-Modified: 2026-09-02T08:02:20.984Z
Languages: [de](https://btlabs.dev/llms/de/glossary/double-opt-in) · [it](https://btlabs.dev/llms/it/glossary/double-opt-in)
See also: [llms.txt](https://btlabs.dev/llms.txt) · [ai.txt (Policy)](https://btlabs.dev/ai.txt) · [identity.json](https://btlabs.dev/identity.json)