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About this tool
Design per-service email aliases so a leaked address names the company that leaked it, with RFC length checks on every address.
This planner picks an email aliasing strategy from your actual constraints — provider, budget, whether you own a domain, whether you need to reply — then generates the per-service addresses and validates them against the limits mail servers enforce: 64 characters for the local part (RFC 5321) and 254 for the whole address. It compares five workable approaches: a forwarding alias service, a catch-all on your own domain, subdomain addressing, RFC 5233 plus tagging, and Gmail's dot variations. The point of a unique address per service is attribution: when spam arrives at an address only one company ever had, you know exactly who leaked or sold it.
Open Email Alias Strategy Planner on AltFTool — it loads instantly in your browser.
Add your input to the workspace.
Adjust the options until the result looks right.
Copy or download the output and put it to work.
Gmail, iCloud, Outlook, Proton, Fastmail and Yahoo differ on what they support, and the ranking reflects that.
Every generated address is checked for local-part length, total length, dot-atom syntax and duplicates.
Plus tags and Gmail dots are marked as strippable, because anyone can normalise them back to your real mailbox.
Yes. Gmail routes anything sent to you+tag@gmail.com to you@gmail.com, and it also ignores every dot in the local part, so first.last@gmail.com and firstlast@gmail.com are the same mailbox. iCloud, Outlook.com, Proton and Fastmail also honour plus tagging; Yahoo does not.
No. A plus tag identifies who leaked your address but does not hide it — deleting everything between the plus and the at-sign recovers your real mailbox, and list brokers routinely do exactly that. If the site must never learn your real address, use a forwarding alias service or a catch-all on a domain you own.
The local part before the @ is capped at 64 octets and the whole address at 254 characters, from RFC 5321 and erratum 1690 to RFC 3696. Many web forms enforce shorter limits of their own, so keep aliases well under those numbers.
No. Use a stable address you control for banking, tax, government and anything with account recovery attached, because losing access to a relay or letting a domain lapse can lock you out permanently. Save aliases for shopping, newsletters, forums and trials.