No. Extraction runs locally in your browser.

Does it validate the addresses?

It checks the format only, not whether the mailbox exists.

Email Extraction

Email extraction pulls every email address out of a block of text, such as a log, an export, or a pasted thread. This tool finds and de-duplicates the addresses in your browser and lets you copy them or save a CSV.

When to use this: You have a messy paste or export and need a clean, de-duplicated list of the addresses in it. Command prefix email-extract:

Client-side only.

About the Email Extraction

Paste any text and pull out every email address, de-duplicated, ready to copy or export as CSV. Runs in your browser.

FAQ

Is my text uploaded?: No. Extraction runs locally in your browser.
Does it validate the addresses?: It checks the format only, not whether the mailbox exists.