Warmup ramps sensibly at low volumes

Warmup no longer leaves small senders stuck near zero. Mailboxes on low volumes now increase by a minimum number of messages each day rather than by a percentage of almost nothing.

What changed

A new sending domain has to build a reputation before mailbox providers will trust it. Warmup does that by starting small and increasing gradually, which is the correct approach and the reason your first emails from a new domain reach inboxes at all.

The increase was calculated as a percentage. That works well once the numbers are meaningful. It fails badly at the start, because a percentage of a very small number is a very small number.

A mailbox sending five a day increased to six. Then to seven. At that rate, reaching a useful daily volume took weeks longer than it should have, and the whole time the campaign was technically running while barely sending.

Warmup now uses whichever is larger: the percentage increase, or a fixed minimum number of additional messages per day. Small senders get the fixed step and climb steadily. Larger ones keep the percentage, which is right for them.

Why it matters

The first weeks after connecting a mailbox are the ones people are least patient with. Somebody has just set up a campaign and wants to see it working. A campaign sending six emails a day does not feel like it is working.

The practical harm was worse than the impatience. A campaign that takes six weeks to reach useful volume is a campaign that misses whatever window it was built for. Outreach tied to an event, a season, or a launch does not get to wait for a ramp.

And the slow ramp did not buy any extra safety. Reputation is built by sending consistently to real addresses that do not complain. A ramp that is too slow is not more careful, it is just slower.

How to use it

Nothing to configure. The new ramp applies automatically to mailboxes in warmup.

Your current warmup limit is shown on the mailbox and on any campaign held by it, so a quiet campaign during warmup is explainable rather than mysterious.

When warmup completes, the mailbox moves to your configured daily limit and campaigns run at full volume.

What warmup still protects against

Sending too much too soon from a new domain is the fastest way to end up filtered, and it is largely irreversible in the short term. Providers form a view of a domain quickly and change it slowly.

Warmup exists because that first impression is the whole game. Getting it wrong means every campaign from that domain underperforms for months, whatever you do afterwards.

The change here is to the shape of the ramp at its lowest point, not to the principle. The ceiling still rises gradually and the mailbox still spends its first weeks sending less than it eventually will.

Warmup and deliverability together

Warmup handles volume. It does not handle who you send to, and the list matters more than the ramp.

A perfectly warmed domain sending to bad addresses will be filtered anyway, because bounces and complaints outweigh a clean ramp. This is the most common way a careful warmup gets wasted.

Verify the list before the first send from a new domain, particularly if the list is old. Addresses go stale faster than people expect, and a stale list is the single most expensive thing to point at a new domain.

What the ramp looks like now

A mailbox starting from nothing climbs by a minimum number of additional messages each day, and once the daily figure is large enough for a percentage to outpace that minimum, the percentage takes over.

The practical effect is a ramp that moves visibly from the first week rather than crawling. A campaign started on a Monday is doing meaningful volume within a sensible number of days instead of a number of weeks.

The top of the ramp is unchanged. Warmup still finishes where your configured daily limit sits, and it still takes a period of consistent sending to get there.

Why percentages fail at the bottom

A percentage increase assumes the number it applies to is already meaningful. Ten percent of a thousand is a hundred, which is a real step. Ten percent of five is half a message, which rounds to one or to nothing depending on which way it goes.

At the very bottom of a ramp, that rounding is the entire increase. The ramp becomes governed by arithmetic rounding rather than by any deliberate decision about sending safety, which is not a good way to run anything.

A minimum step removes the rounding from the decision. The ramp increases because it was designed to, at a rate somebody chose.

During warmup

Campaigns using a warming mailbox send at the current limit rather than pausing. Sending something every day is what builds the reputation, so a campaign that sits idle during warmup is defeating the purpose.

The current limit is shown on the mailbox and on the campaign, so a low send count during this period is explained rather than looking like a fault.

If you have several mailboxes and only one is warming, campaigns can be split across them, with the warming one carrying its share and the established ones carrying the rest.

If you are already partway through

Mailboxes already in warmup picked up the new ramp automatically rather than restarting. A mailbox that had been crawling at seven a day started climbing properly from the day the change went out, keeping the reputation it had already built.

Nothing was reset, because resetting would have thrown away the part of warmup that was working. The slow ramp still built reputation, it just built it slower than it needed to.

If a mailbox had been stuck at a low volume for weeks, the visible effect was a noticeable jump in daily sending over the following days.

Availability

Live now on all plans for mailboxes in warmup, applied automatically to mailboxes already partway through their ramp.