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SMTP Relay

Transactional email from your app,
on the same account as your marketing.

Password resets, receipts, invites and alerts don't come from a campaign builder — they come from your code. Point it at our SMTP host and that mail goes out signed with the same domain, through the same sending infrastructure, billed on the same invoice as everything else you send. One sending reputation, not two.

Included on Business and Agency. Requires a verified sending domain.

your-app · smtp settings

Host smtp.cleverlybox.com Port 587 (STARTTLS) · 465 (TLS) Username issued in your dashboard Password shown once, at issue From hello@your-verified-domain.com

The host is real. The credential is yours alone — issued, rotated and revoked from the dashboard.

From nothing to sending

Three steps, and none of them are a sales call.

01 / VERIFY

Verify your sending domain

Add the domain, publish the DKIM and SPF records we generate, and let it verify. This is not optional and it is not a formality — no credential is issued for a domain you have not proven you own.

02 / ISSUE

Issue an SMTP credential

One click in the dashboard. The password is displayed once, at the moment of issue, and stored only as a hash — so we cannot show it to you again. Put it straight into your secret manager.

03 / POINT

Point your app at us

Change four settings — host, port, username, password. Nothing else in your application changes. Your framework's mailer already speaks SMTP; it doesn't need to learn anything new.

Issuing an SMTP credential in the CleverlyBox dashboard

Issue, rotate and revoke credentials from the dashboard.

The relay usage meter, showing messages used against the monthly allowance

The usage meter — what you've sent, what's left, what you topped up.

What you get

Relay volume is included, not extra.

Relay messages are metered separately from your marketing emails — sending a month of receipts does not eat the campaign allowance you bought. Run out and you can top up; the top-up doesn't expire.

  Business Agency
Relay messages included / month 10,00050,000
SMTP credentials 210
Rate ceiling 500 / hr2,000 / hr
Prepaid top-ups

The relay is not on Free or Starter. That is a deliberate line, not an upsell trick — relayed mail goes out over shared infrastructure, and we would rather carry it for accounts we can hold accountable.

Top-ups

Buy more when you need it.

10,000 relay messages $10
50,000 relay messages $40
100,000 relay messages $70

Top-up credits never expire and are spent only after your monthly allowance is used up — so a top-up bought in a busy month is still there in a quiet one.

Protection

The guardrails are there to protect your domain.

A relay is a loaded gun pointed at your own sending reputation: a leaked credential or a runaway loop in your code sends thousands of messages under your domain. These three exist to stop that becoming your problem.

01 / DKIM REQUIRED

No unverified senders. Ever.

Credentials are issued only against a verified sending domain, and every message is DKIM-signed with that domain's key. There is no path — no support ticket, no exception — that relays mail for a domain you have not proven you own.

02 / RATE CEILING

A ceiling on how fast it can go wrong.

500/hr on Business, 2,000/hr on Agency. A bug that tries to send a million messages overnight hits the ceiling instead of your reputation. You will see it in the meter long before a mailbox provider sees it in their spam trap.

03 / REPUTATION

Bounces and complaints are watched.

We monitor the bounce and complaint rate on every credential. If one crosses the threshold, that credential is suspended automatically and you are told. It is a blunt instrument, and it is meant to be — an hour of suspended relay is cheaper than a blocklisted domain.

What this is not

SMTP today. That's the whole list.

We would rather you find this out here than three days into an integration. The relay speaks SMTP and nothing else. An HTTP send interface is on the roadmap; we are not going to give you a date for it, because a date we invent today is a promise we break later.

How sending works →
SMTP relay, ports 587 / 465Available now
DKIM signing from your domainAvailable now
Usage meter & prepaid top-upsAvailable now
HTTP send interfaceOn the roadmap
Customer-facing delivery webhooksNot yet
Inbound / reply parsingNot yet

No dates, because we do not have honest ones. What is listed as available is running today.

Questions

The things you'd ask before rewiring your app.

Do I still need my own Amazon SES or SendGrid account?

Not for transactional mail — that is exactly what this replaces. Your app hands its mail to smtp.cleverlybox.com and we carry it from there, DKIM-signed with your sending domain. If you'd rather own the upstream reputation yourself, Business and Agency can still connect their own sending provider for campaigns; the two are not exclusive.

Does relay volume come out of my marketing email allowance?

No. They are two separate meters. Your 10,000 relay messages on Business sit alongside your campaign allowance, not inside it — a heavy month of password resets cannot quietly eat the newsletter you were about to send.

What counts as one relay message?

One message to one recipient, accepted by the relay for delivery. A receipt to one customer is one. The same message addressed to three people is three. We count what we hand upstream, and the meter in your dashboard shows it as it happens.

What actually happens when I hit the cap?

The message is dropped, not queued. We do not hold it, we do not retry it, and we do not silently deliver it and bill you later — it is rejected, the reason is recorded against the credential, and it shows in your usage meter. That is deliberately unforgiving, so buy a top-up before you run out rather than after. If a credential starts rejecting, the meter tells you why in one glance.

Can I resell this to my clients?

On Agency, yes — that is what 10 credentials are for. Issue one per client, each locked to that client's verified domain, and revoke it the day the engagement ends. Each credential is metered and monitored on its own, so one client's bad list does not suspend another client's mail.

Which plans include the relay?

Business ($50/mo) and Agency ($150/mo). Not Free, not Starter. The full breakdown — included volume, credentials, rate ceilings and top-up prices — is on the pricing page, and the step-by-step is in the setup guide.

Your app's mail, on infrastructure you already pay for.

Included on Business and Agency, metered in the open, and switched off automatically if it ever starts hurting your domain.