Solutions / Forwarding & Delegated Sending
Forwarding is the hardest thing in email. We made it a product feature.
Shared inboxes, alias services, send-as-me products, CRM mail sync, assistant tools that answer on a user's behalf. Any product that moves mail between identities collides head-on with modern authentication. Most break DMARC and strand replies. Ours don't.
The context
Why this is harder than it looks.
Email authentication was designed to stop exactly what forwarding products do on purpose: a message claiming one identity, transmitted by infrastructure belonging to another. A naive forward keeps the original From while sending from your servers. SPF fails, because your IP isn’t in their record. The original DKIM signature often breaks in transit handling. And DMARC, which requires alignment between the visible From and an authenticated domain, fails closed. The forwarded message lands in spam or gets rejected outright, and your product looks broken.
The robust solutions involve careful identity handling. Re-author the message under an identity you can legitimately authenticate. Preserve the parts humans care about: who it’s from, who to reply to, the thread. Re-sign cleanly so exactly one valid signature arrives. Every detail matters here. A duplicated Message-ID header, a stale broken signature left next to a new one, a Reply-To that drops the original sender. Each one is a deliverability or usability failure waiting in production.
Underneath that, delegated-sending products are multi-tenant senders whether they admit it or not. Every user is an identity with its own behavior and its own risk. The platform needs per-identity reputation, per-identity rate gates, suppression no user can route around, and real mailboxes when the product’s identities must also receive.
Your challenges
What this looks like from where you sit.
Forwarded mail lands in spam because SPF, DKIM, and DMARC weren’t designed for what your product does. Your users blame your product.
Replies to forwarded or delegated mail go to the wrong place, breaking threads and trust.
One user’s behavior, or one compromised account, damages sending reputation shared by all your users.
Your identities can send but not receive, so bounces, replies, and out-of-office notices disappear.
Every receiver-side authentication change threatens to break your core feature overnight.
How Egressif helps
What changes when one team owns the outcome.
DMARC-surviving forwarding
Forwarded and recrafted mail is re-authored under properly authenticated identities, with the originals preserved where humans need them: display names, reply paths, threads. Signatures are re-applied cleanly, so exactly one valid, aligned signature arrives.
Reply paths that survive the trip
Reply-To handling preserves the original correspondents through the forward. "Reply" reaches the human who wrote the message. That is the difference between a delegation product and a dead-letter office.
Header hygiene under modification
Message-ID handling, duplicate-header collapse, and signature replacement are done correctly on every modified message. These are the quiet details strict receivers reject mail over.
Per-user identity isolation
Each user’s sending runs as its own identity with its own reputation and rate budget. One compromised account is one contained identity, not a product-wide placement incident.
Receiving-capable identities
Hosted mailboxes (IMAP/SMTP/JMAP) give your product’s identities a real receiving side. Replies, bounces, and threads land where your product can use them, with server-side filtering to route what arrives.
We track the receivers so you don’t
When mailbox providers tighten authentication or change forwarding treatment, that’s our operational problem to absorb. Your feature keeps working while competitors scramble.
The problem
Your send-as-user feature worked for two years. Then a major provider tightened DMARC handling and your forwarded mail started bouncing with "550 5.7.509 unauthenticated email is not accepted". Support tickets tripled overnight, and the fix meant re-architecting identity handling under incident pressure.
With Egressif
On Egressif, identity handling was enforcement-grade from day one: aligned authentication on every outbound message regardless of origin. The provider’s change was a non-event. You read about competitors’ outages on a forum.
Build on forwarding that actually works.
Tell us where you are today: domains, volume, providers, what hurts. We will come back with a concrete way forward.