Forward client email from any other provider
The same four moves work anywhere with rules or filters — plus what to do about the providers that restrict forwarding.
Walkthrough · 4 min read
Almost every mail provider has the same feature under a different name: rules, filters, sieve, or "message handling". If yours can act on incoming mail at all, it can do this, and the shape is always the same.
- Find the rules or filters screen in your provider’s web interface. Not in a desktop mail app — a rule that lives in an app only runs while that app is running, which is not what you want here.
- Make a condition that matches one client: their address as the sender, or their company domain.
- Choose the action that sends a copy onward. It may be called forward, redirect, or "send a copy to". Any of them is fine.
- Answer a confirmation if your provider asks the destination to agree — the message will be on that client’s email thread in Stria, as plain text.
- Forward one real message by hand to prove the address works, then wait for a genuine one to prove the rule does.
Two providers freelancers actually use are worth naming, because each has a wrinkle.
- Fastmail: Settings, then Filters and Rules, then create a rule. Conditions can match the sender, the subject, the body or anything in the message; the action you want is "Send a copy to", which accepts an outside address. Rules run on incoming mail only, and there is generous room for them — a thousand per user — so one per client is not extravagant. Fastmail’s own rules page points at its mail-forwarding notes for known issues, and it is worth a glance before you rely on it.
- Proton Mail: forwarding is a PAID feature. On a free account there is no auto-forwarding to set up at all, and the honest answer is to forward by hand or move that client’s mail elsewhere. On a paid plan it is Settings, then "Forward and auto-reply", then add a forwarding rule, optionally with a condition. Proton then emails the DESTINATION and waits for it to accept before anything flows.
Important: Proton’s confirmation is an accept-or-decline request sent to the destination, not just a link, and Stria cannot accept it for you — it has no mailbox and does not act on your behalf. The request arrives on the client’s email thread like any other message, so you can read it there and use the accept link in it. If that message never appears, forwarding is not going to start, and forwarding by hand is the answer rather than a workaround.
Note: Proton also warns that forwarding to a non-Proton address turns off end-to-end encryption for the forwarding address. That is a real trade and it is theirs to explain, not ours — read their note before you decide.
Note: Some providers only offer "redirect" rather than "forward". Both work. The difference is whose name the message appears under when it arrives, and Stria attributes a forwarded message to the person who originally wrote it wherever the headers allow.
If your provider cannot do any of this, nothing is lost — forwarding by hand is the ordinary way to use the address, and it is what the address was built for. The rule is a convenience, not a requirement.
Copy a client’s drop address — in your Stria workspace.
Check the test message arrived — in your Stria workspace.