Email sending domains
When an agent follows up with a lead, that mail goes out from Erdo’s own address by default. The recipient sees a sender they have never heard of, on a domain that has nothing to do with the business they enquired with — which is bad for replies and worse for the spam filter, because nothing about the message lines up with the site they just filled a form on. A sending domain fixes that at the source: verify a domain you own, and outreach leaves ashello@acme.com, signed off in your brand’s name.
Verification is entirely DNS — a few records at whichever host runs your domain,
the same motion you already went through for a custom pages
domain. No mail server to run, no mailbox to hand over, no
credentials to give Erdo.
Only outreach moves to your domain: the mail agents and automations send on
your behalf — lead follow-ups, replies to enquiries, alerts an
automation sends out. Erdo’s own product mail — team invites,
account notifications — keeps coming from Erdo, because that mail is from Erdo
and dressing it up as your brand would be misleading rather than helpful.
Choose the name to send from
You can verify an apex domain (acme.com) or any subdomain (hello.acme.com,
news.acme.com) — Erdo does not require the name to match your pages domain, and
does not care whether you host anything on it.
An organization has one sending domain: everything Erdo sends on your behalf
leaves from one identity, so which domain that is should never be ambiguous. To
switch domains, remove the current one (sends fall back to Erdo’s address) and
register the new one — so the name is worth choosing deliberately.
A subdomain is usually the better choice, for one reason worth understanding
before you pick. Once you verify a domain, the reputation of everything Erdo
sends attaches to that name. Send from the apex and automated outreach shares a
reputation with the mail your team sends by hand from their own mailboxes; a bad
week for one is a bad week for the other. A subdomain keeps them separate, so a
deliverability problem on outreach never touches your everyday business mail.
We suggest hello. — it reads like a place a person writes from, which is the
point of sending as your own business. Anything warm works (team., contact.);
avoid names that read as bulk mail (marketing., promo.), and avoid send.,
which collides with the name Erdo’s return-path records already use. If you pick
hello., give the mailbox a different name — sales@hello.acme.com reads well,
hello@hello.acme.com does not.
There is also a hard constraint if you want Erdo to receive at the name —
which is what brings replies back in, so an agent can read what a lead wrote and
act on it rather than only your team seeing it.
Receiving needs an MX record on the name itself, and a name can only have one set
of MX records — if acme.com already points its MX at Google Workspace or
Microsoft 365, it cannot also deliver to Erdo. Erdo checks for existing MX records
when you register a domain, and a name that already routes mail somewhere is
registered sending-only: no MX record appears among the ones to add, so
nothing you (or the DNS admin you email the instructions to) could paste would
take your mailbox down. In that setup a forwarding mailbox is required, since
replies need somewhere real to land. To also receive through Erdo, verify a
subdomain such as hello.acme.com instead, which has no mailbox MX of its own to
displace.
Set it up
1
Register the domain
Open Settings → Domains, go to Email sending, and add the domain you
want to send from. Erdo registers it and immediately hands back the DNS
records to create.
2
Create the DNS records
Add them at whatever host answers for your domain — your registrar, Cloudflare,
Route 53. Every record is shown with a copy button, and the values must be
entered exactly as given. If someone else runs your DNS, email them the
instructions straight from the domain’s card — the whole record set arrives in
one message, which is safer than pasting values into chat one at a time.
3
Wait for verification
Erdo re-checks the domain roughly every ten minutes until every record is
visible and correct, then marks it active. DNS changes usually surface
within minutes, but a host with long TTLs can take a few hours — nothing is
wrong until the records are live and Erdo still can’t see them.
4
Set how it signs
Choose the display name, the local part of the address (
hello unless you
change it), and the mailbox replies should reach. These are editable at any
time and take effect on the next send.The records, and what each one is for
Erdo generates the exact values for your domain; there is nothing to compose yourself. What they do:
Because the return path sits on a
send. subdomain rather than on the name
itself, these records do not touch your existing mail routing: adding them cannot
divert mail to your team’s mailboxes.
Once the domain is active, DMARC alignment is automatic. Every message is
sent from an address on the verified domain, signed with a DKIM key published by
that domain, with a return path inside it — so both the DKIM and SPF checks align
with the visible From address, which is what a DMARC policy actually asks for.
You get this by construction; there is no setting to enable.
What changes once it’s active
Outreach switches to<local-part>@<your-domain> with your display name, and the
sign-off at the bottom of composed messages changes from Erdo’s to your brand’s,
so nothing in the message contradicts the sender.
What happens when someone replies depends on whether you turned receiving on,
because that is the difference between the reply going somewhere Erdo can see and
going somewhere it cannot.
With receiving on, the mail goes out with Reply-To set to the sending
address itself — which is a name that now delivers to Erdo — so a reply lands in
two places at once. It is stored against the domain, where an agent can read it
and act on it —
answer the question, book the meeting, note the objection against the lead — and a
copy is forwarded straight to the mailbox you nominated, so your team reads it in
the inbox they already live in rather than logging into Erdo to find out someone
wrote back. On that forwarded copy the Reply-To is set to the person who
actually wrote, not to Erdo: hit reply in your own mailbox and your answer goes
directly to the lead, from your real address, with Erdo out of the loop entirely.
Nothing is trapped in Erdo waiting for you to notice it.
With receiving off — which is the right choice when the name already routes
mail to Google Workspace or Microsoft 365 — nothing changes about where mail
lands. Outreach carries a Reply-To pointing at the mailbox you nominated, so
someone who hits reply reaches a real person at your company directly. That reply
never passes through Erdo, so Erdo has no record of it and no agent can act on it.
Delete a sending domain and nothing breaks: outreach falls straight back to
Erdo’s default sender on the next send, and replies to the old address stop
reaching Erdo.
Deliverability is now your domain’s
This is the trade you are making, and it is worth being explicit about. On Erdo’s shared sending domain your mail inherits a reputation that already exists. On your own domain you start from nothing, and everything Erdo sends builds — or damages — the reputation of a name you also use for everything else. Practically, that means:- Warm up gradually. A domain that has never sent automated mail and then emits a few hundred messages in a day looks exactly like a compromised domain to a spam filter. Start with the follow-ups you’d send anyway and let volume grow over days, not in one afternoon.
- Keep the volume modest. Erdo caps an organization at 50 distinct recipients per day across all its outbound mail, and verifying a domain does not raise that cap. It is a deliberate guard: outreach from an agent is meant to be a handful of relevant follow-ups, not a campaign send.
- Mail people who asked to hear from you. Follow-ups to leads who filled in your form perform well and get few complaints. Cold lists on a freshly verified domain are the fastest way to teach the receiving side to distrust your name.
- Leave DMARC on
p=nonefor a while. If Erdo offered you the DMARC record, it deliberately suggests monitoring rather than enforcement, so that a misconfiguration somewhere else in your mail setup doesn’t start bouncing legitimate mail the day you add it.
API
Sending domains are org-scoped and require an org admin, like custom domains. A domain is addressed by its name — the natural identifier — and a name registered to another organization answers404 with no
hint that it exists.
List the org’s sending domains with their live status and DNS records:
domain can be
left off, since you have one sending domain and the read resolves it:
{from_email, from_name, subject, text_preview, received_at, forwarded_at}. text_preview is the opening of the message —
enough to separate a real answer from an out-of-office without pulling whole
bodies. forwarded_at says when the copy went to your nominated mailbox; empty
means the message is in Erdo only, so nobody on your side has necessarily seen
it yet. A sending-only domain returns an empty list, which is the configuration
working as chosen rather than a fault.
MCP tools
Troubleshooting
Related
Custom domains
The same motion for your published pages — serve them from your own hostname.
Sent email
The record of everything Erdo has sent for you, including the address it sent from.
Automations
Where most outreach is sent from.
Inboxes
An address Erdo owns and can receive at, for agents that need to read mail.