New sending domain: raising volume without hurting your reputation

You launch an application, switch sending providers or plug in a new domain. Overnight, thousands of emails leave from an address nobody knows. That is exactly the profile mailbox providers watch for: a sender with no history that suddenly changes scale. This article explains why, and how to ramp up in steps instead of all at once.

The guidance quoted here comes from Google's official page for senders to Gmail (sources at the end). Other providers have their own rules: check their documentation rather than relying on one provider's.

Why a provider distrusts a sender with no history

A mailbox provider doesn't know your intentions. It knows your habits: how many messages you send, how often, how many are rejected, how many are reported as spam. A domain or sending address that has never sent anything has no habits to compare with, and a sudden mass send looks a lot like what spam does.

Google says so directly in its guidelines: avoid sudden volume spikes if you have no history of sending large volumes. Its example: suddenly doubling previously sent volumes could result in rate limiting or reputation drops.

The volume Gmail accepts from you is therefore not an entitlement. It is built from your previous sending.

What sets how fast you can ramp up

According to Google, three factors matter:

• The amount of email sent. The more you send, the more slowly you should increase.
• The frequency. Sending daily lets you increase faster than sending weekly.
• Recipient feedback. Sending only to people who subscribed, and letting them unsubscribe, limits complaints.

Gmail tracks volume, feedback and limits per domain and per IP address. The quotas tied to your domain (DKIM and SPF) are yours alone. An IP address quota, on the other hand, is shared by every sender using that address: when the address hits its quota, all the domains sending from it are affected. Google also recommends that, if you send through a provider on a shared IP address, you make sure that address isn't on any blocklist.

When this applies even if you only send transactional email

Transactional email follows your users' behavior, so you might expect volume to rise slowly by itself. Several situations still create spikes:

• A migration. You move from the old provider to the new one and everything switches overnight.
• A launch or a publicity push. Sign-ups surge, and so do confirmation emails.
• A batch send. A notice to existing users, a change of terms, a billing reminder.
• A new sending domain. You split your streams, as suggested in Transactional or marketing email: where is the line?, and the new domain starts from zero.
• A long pause. A domain that hasn't sent anything for months is no longer "known" the way it was.

In every case the question is the same: how far is tomorrow's volume from yesterday's?

Ramp up in steps

Here is a method, to adapt to your situation. Google publishes no numeric schedule; the right numbers depend on your volume, your recipients and how often you send.

1. Start with the most reliable recipients

Google recommends starting at a low volume, to engaged users. For an application, those are people who just signed up or who log in regularly: they expect your messages and are unlikely to report them.

2. Send at a steady rate

Avoid bursts. Volume spread through the day is received better than a large batch sent in a few minutes. For a batch send, spread it over several hours, or several days.

3. Increase, then look before continuing

After each step, check the signals before moving to the next one:

• bounces and deferred messages (see An email didn't arrive: how to find out why);
• spam complaints;
• for Gmail, domain reputation and the spam rate in Postmaster Tools.

Google asks you to keep the spam rate reported in Postmaster Tools below 0.10% and to avoid ever reaching 0.30%.

4. If it goes wrong, back off

If messages start bouncing or being deferred, Google recommends reducing the volume until the SMTP error rate decreases, then increasing slowly again. If bounces continue even at low volume, review individual messages to identify the problem. Google suggests, for example, sending a blank test message to see whether it runs into the same difficulties.

5. Change one thing at a time

If you change the format of your messages or your sending infrastructure, Google advises increasing the modified share of traffic separately. Switching providers, changing the HTML template and opening a new domain in the same week means you won't know what caused the problem.

What to do when Gmail says "too fast"

When you exceed a quota, Gmail typically rejects the message with SMTP code 4.7.28. The code starts with 4: it is a temporary failure, and the sending server should retry later. Google gives a procedure:

1. Don't send anything for at least 10 minutes.
2. Identify the cause. If the error message doesn't say which quota was exceeded (DKIM, SPF or IP address), assume all three.
3. After 10 minutes, send over a single connection. If it fails, wait another 10 minutes; if it succeeds, add connections one at a time.

If you see deferred messages, that is the signal that your pace exceeds what the recipient accepts for now: don't try to resend them in a burst.

The basics that volume can't make up for

Ramping up slowly doesn't replace the rest. For all senders to Gmail, Google requires a domain authenticated with SPF or DKIM, and with SPF, DKIM and DMARC for bulk senders, along with a TLS connection. The sending IP address must also have a reverse DNS (PTR) record consistent with its hostname. Setup details are in SPF, DKIM and DMARC: setting up a sending domain.

One more point: a promotion mixed into a receipt, or a message sent to people who didn't ask for it, produces complaints that no ramp-up can offset.

A checklist

1. Estimate the expected volume of the first week, then of the first month.
2. Authenticate the domain before the first send, and wait for the verification to pass.
3. Start small, with your most reliable recipients.
4. Spread sends out, with no bursts or spikes.
5. Watch bounces, deferrals and complaints at each step.
6. Back off as soon as errors rise, then resume more slowly.
7. Separate changes: one at a time (provider, template, domain).
8. Warn your provider before a planned mass send.

At Duva, a recent account that sends a lot, or a rate far above its usual one, can have a message held for review before it is sent. The API reference explains how to avoid it: raise the volume gradually, or write to us before a mass send. The terms of use specify what is allowed.

Sources

• Email sender guidelines (Google), sections "Increase sending volume slowly", "Shared IP addresses" and "Spam rate", which also contain the 4.7.28 code. Read on October 11, 2026.