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Documentation/Using MailFlat/Inboxes & addresses

Opening & managing inboxes

An inbox is a real, permanent address. Open one in seconds, use it anywhere, keep it as long as you like.

Open your first inbox

  1. Click the + button
    Top of the All inboxes list. It opens the new-inbox dialog.
  2. Type a name
    Lowercase letters, digits and hyphens, up to 30 characters, e.g. shop. Leave it blank and we generate one for you.
  3. Pick a retention window (optional)
    How long messages stay before they are purged. Defaults to your plan maximum; you can always choose less, never more.
  4. Create
    You get something like shop@a7f2c.mailflat.net. Copy it and paste it wherever you need an address.
The address is permanent
MailFlat is not throwaway mail. The address lives until you delete it. Only the messages inside expire. Reuse the same address for the same service forever.

What the parts of the address mean

The namespace is random on purpose: nobody can guess your other addresses from one you handed out.
Tags: one address, many sendersshop+promo@… → filter by #promo
Anything after a + is a tag. Mail sent to shop+promo@a7f2c.mailflat.net lands in the same shop inbox, tagged #promo.
Give each service its own tag and you can tell instantly who leaked or sold your address, and filter the list down to just that sender.
Custom names and subdomainsFree gets a random namespace
On paid plans you can choose the part after the @ too, and open inboxes on your own domain (see Custom Domains). On Free the namespace is always random, that is the anti-squatting rule, not a paywall trick: it stops anyone from re-claiming an address you deleted.

Deleting: inbox vs messages

Two different things, easy to mix up:
• Delete a message: the 🗑 next to a message. Removes just that mail.
• Burn an inbox: empties every message but keeps the address working.
• Delete an inbox: the 🗑 in the inbox list. The address is released and its mail goes with it.
Deleting is permanent
There is no trash and no undo. A deleted inbox cannot be recreated with the same address (the namespace is regenerated), so delete only when you truly mean it.