Forward Emails by Sender, Subject, or Content

You probably do not want to forward every single email to someone else. You want to forward some of them — invoices to your accountant, client messages to your team lead, urgent alerts to your personal phone. The rest should stay in your inbox where they belong.

TrekMail makes this easy with conditional forwarding. You set up a mail filter that watches for specific emails and automatically forwards just those to another address. Everything else is untouched.

This guide shows you exactly how to do it, with real-world examples you can copy and adapt.

Unconditional vs. conditional forwarding

TrekMail offers two different ways to forward email, and they serve very different purposes:

Unconditional forwarding is found on the Forwarding tab in your mailbox settings. It forwards every email that arrives in your mailbox to another address. All of them, no exceptions. This is useful when you want a complete mirror of your mailbox somewhere else — for example, during a migration or if you are consolidating inboxes.

Conditional forwarding is set up on the Filters tab in your mailbox settings. It forwards only the emails that match conditions you define. This is what most people actually need, and it is what the rest of this guide covers.

If you are not sure which one you need, ask yourself: "Do I want every email forwarded, or just some?" If the answer is "just some," you want a filter.

Real-world use cases with step-by-step setup

Here are four common scenarios. Each one includes the exact settings you need to enter in TrekMail.

Use case 1: Forward invoices from a vendor to your accountant

The situation: You receive monthly invoices from FreshBooks. Your accountant Sara needs a copy of each one, but you do not want to manually forward them every time.

How to set it up:

1. Go to Mailboxes in the sidebar, then click Settings on your mailbox.
2. Click the Filters tab, then click + Add filter.
3. Name the filter: Forward FreshBooks invoices to Sara
4. Set the condition:
   • Field: From
   • Comparison: contains
   • Value: freshbooks.com
5. Set the action:
   • Action: Forward a copy to
   • Value: sara@myaccountant.com
6. Check Stop processing further filters.
7. Click Save filter.

From now on, every email from FreshBooks will automatically be copied to Sara. You will still have the original in your mailbox.

Optional upgrade: Add a second action to also move the email to an "Invoices" folder. Click + Add action, choose Move to folder, and select the folder. Now invoices are forwarded to Sara and organized for you at the same time.

Use case 2: Forward emails from a specific client to your team

The situation: You manage a client account for Acme Corp. Your project manager needs to see every email they send you, but you do not want to CC them manually on every reply.

How to set it up:

1. Go to Mailboxes → Settings → Filters tab → + Add filter.
2. Name the filter: Forward Acme Corp to project manager
3. Set the condition:
   • Field: From
   • Comparison: contains
   • Value: acmecorp.com
4. Set the action:
   • Action: Forward a copy to
   • Value: pm@myagency.com
5. Check Stop processing further filters.
6. Click Save filter.

Every email from anyone at Acme Corp (sales, billing, their CEO — anyone with an @acmecorp.com address) gets copied to your project manager.

Use case 3: Forward urgent emails to your personal phone

The situation: You want emails with "urgent" in the subject line to reach you immediately, even when you are away from your desk. Your phone has a personal email address that pushes notifications.

How to set it up:

1. Go to Mailboxes → Settings → Filters tab → + Add filter.
2. Name the filter: Urgent to phone
3. Set the condition:
   • Field: Subject
   • Comparison: contains
   • Value: urgent
4. Set the action:
   • Action: Forward a copy to
   • Value: yourname@gmail.com
5. Optionally add a second action: Mark as flagged (so it also stands out when you check your TrekMail inbox later).
6. Check Stop processing further filters.
7. Click Save filter.

Now any email with "urgent" anywhere in the subject line gets a copy sent to your personal email and shows up flagged in TrekMail.

Tip: If people in your organization use a specific tag like "[URGENT]" or "PRIORITY," use that as your value instead of a common word. The more specific your condition, the fewer false matches you will get.

Use case 4: Forward order confirmations to a CRM inbox

The situation: Your team uses a CRM that has an inbound email address for logging interactions. You want purchase confirmations and receipts to automatically appear in the CRM.

How to set it up:

1. Go to Mailboxes → Settings → Filters tab → + Add filter.
2. Name the filter: Order confirmations to CRM
3. Set the match type to Any condition (because you want to catch emails that match any of these patterns, not all of them at once).
4. Add your conditions:
   • Condition 1 — Subject contains order confirmation
   • Condition 2 — Subject contains receipt
   • Condition 3 — Subject contains purchase confirmed
5. Set the action:
   • Action: Forward a copy to
   • Value: inbox@yourcrm.com
6. Click Save filter.

This casts a wider net by using "Any condition," so an email matching any one of those three subject patterns gets forwarded to your CRM.

"Forward a copy" vs. "Forward (no copy)" — which one should you use?

These two actions sound similar but behave very differently:

Forward a copy to sends a duplicate of the email to the target address. The original email stays in your mailbox. You can read it, reply to it, and organize it as usual. This is the safer and more common choice.

Forward (no copy) redirects the email to the target address and removes it from your mailbox entirely. It is as if the email was never delivered to you. Use this only when you genuinely do not need to see the email at all — for example, routing support tickets to a shared queue that you monitor separately.

Our recommendation: Start with "Forward a copy to." You can always switch to "Forward (no copy)" later once you are confident the email is being handled elsewhere and you truly do not need a local copy.

What happens to the forwarded email?

A few things you might be wondering about:

Does the original sender know the email was forwarded? No. Forwarding happens silently on the server. The sender receives no notification that their email was copied or redirected to another address.

Does the "From" address change on the forwarded copy? The forwarded email will still show the original sender's name and address in the body and headers. However, the envelope sender (the technical behind-the-scenes address used for delivery) is rewritten using something called SRS (Sender Rewriting Scheme). In plain terms, this means the forwarded email passes the security checks of the receiving mail server. You do not need to do anything — TrekMail handles this automatically. The recipient sees the email as coming from the original sender, and everything just works.

Can the recipient reply to the forwarded email? Yes. When they hit reply, it goes to the original sender, not to your TrekMail mailbox. This is usually the desired behavior — it keeps the conversation direct.

Gotchas and limits

Before you set up conditional forwarding, keep these in mind:

You cannot forward to yourself. If your mailbox address is hello@yourdomain.com, you cannot set up a filter that forwards to hello@yourdomain.com. TrekMail will block this because it would create an infinite loop.

The target address must be valid. When you save a filter with a forwarding action, TrekMail checks that the target email address has valid mail server records (called MX records). If the address does not look deliverable, you will see an error. Double-check for typos.

Forwarding filters have separate limits. On the Pro plan, you can have up to 5 filters that include a forwarding action (out of your 10 total filters). On the Agency plan, you can have up to 25 forwarding filters (out of 50 total). Filters that only move, flag, or discard do not count toward the forwarding limit.

Starter plans include direct (unconditional) forwarding only. Conditional forwarding via mail filters requires Pro or Agency. If you are on the Starter plan, you can forward all mail from a mailbox using the Forwarding tab, but you cannot set up filter-based forwarding rules.

Emails caught as spam are not forwarded. TrekMail's spam filter runs before your mail filters. If an email is flagged as spam, it goes straight to Junk and your forwarding filter never sees it. This is actually a good thing — it prevents you from accidentally forwarding spam to your accountant or CRM.

Forwarded emails count toward normal sending volume. Each forwarded email counts as one outgoing message. If you forward very high volumes, you may approach your daily sending limits. This is rarely an issue for normal business use, but worth knowing if you set up broad forwarding rules.

Combining forwarding with other actions

Forwarding does not have to be the only thing a filter does. You can add multiple actions to a single filter. Some useful combinations:

• Forward a copy + Move to folder: The email goes to your accountant AND gets filed in your Invoices folder automatically.
• Forward a copy + Mark as flagged: The email goes to your project manager AND shows up flagged in your inbox so you remember to follow up.
• Forward (no copy) + (nothing else needed): The email is redirected entirely. Since it leaves your mailbox, other actions like "Move to folder" would have no effect.

To add multiple actions, click + Add action in the filter dialog and choose the additional action from the dropdown.

Quick-start summary

If you just want to get a conditional forward running in sixty seconds:

1. Go to Mailboxes → click Settings on your mailbox → Filters tab.
2. Click + Add filter.
3. Set one condition (e.g., From contains vendor.com).
4. Set the action to Forward a copy to and type the target email address.
5. Click Save filter.

Done. Matching emails will be forwarded automatically from this point on.