Deliverability is not a growth lever. It is a floor: below it nothing else in this system matters, because a perfectly qualified account that never sees the message is identical to an account you never found.
Most of the defaults on this page are conservative on purpose, and one of them — tracking — is the one people most want to change and should not.
Why tracking is off by default#
Open and click tracking is off, for every campaign, on every workspace. This is not a setting we forgot to turn on. It is off because turning it on costs replies, and the size of the cost is known.
Cold emails sent without open or click tracking replied at 7.4%. The same corpus with tracking enabled replied at 4.4%.
Drawn from an analysis of roughly 31 million cold emails. Tracking pixels and rewritten links are themselves spam signals, and the deliverability cost outweighs the value of the data they collect.
Bars are scaled against a 10% ceiling. Removing tracking is associated with roughly two-thirds more replies on the same corpus.
Three mechanisms explain it, and all three are things a filter can see.
- The pixel is a remote image in a text-only message. A one-by-one transparent image loaded from a third-party host, in an email that otherwise contains no images, is a pattern filters were built to notice.
- Link rewriting breaks the visible-destination rule. A link whose text says one domain and whose href points at a tracking host is exactly the shape of a phishing message.
- Tracking domains carry other people’s reputation. A shared tracking host has been used by everyone else on the platform, and you inherit whatever they did with it.
This is also why opens are not a signal. A number you cannot cite, derived from a mechanism that costs you replies, is not evidence of anything.
Warmup#
A new mailbox has no sending history, and a mailbox with no history that begins sending fifty messages a day looks exactly like a compromised account. Warmup builds the history first.
- Duration
- 14–21 days, extended if engagement is poor
- Traffic
- genuine conversational exchanges, not one-word replies
- Volume
- starts in single digits, increases daily
- Campaign traffic
- blocked until warmup completes
- Runs alongside
- yes — warmup continues at a lower rate during normal sending
Warmup cannot be skipped, and the ramp cannot be shortened. It can be extended, and it extends itself automatically if the mailbox is landing in spam folders during the period.
Send windows#
Messages go out in the recipient’s working hours, in the recipient’s timezone. Not yours, and not the browser’s — see send windows for how the timezone is resolved.
| Rule | Default | Why |
|---|---|---|
| Hours | 08:00–17:00 recipient-local | Mail arriving at 03:00 reads as automated before it is read at all |
| Days | Monday–Friday | Weekend cold mail is deleted at a higher rate and complained about at a higher rate |
| Holidays | Excluded by region | A message arriving on a public holiday is buried by the backlog on the next working day |
| Cadence | Jittered, minimum 90s gap | A fixed interval is the clearest possible machine signature |
| Burst | None | Volume is spread across the window rather than issued at the top of the hour |
Volume ramp#
After warmup a mailbox does not jump to its cap. It ramps, and the ramp is not editable.
| Period | New messages per day | Note |
|---|---|---|
| Warmup, days 1–14 | 0 campaign messages | Warmup traffic only |
| Week 3 | up to 10 | First campaign traffic |
| Week 4 | up to 20 | Held here if bounce rate is above 2% |
| Week 5 | up to 35 | |
| Week 6 onward | up to the configured cap, default 50 | The cap is per mailbox, not per campaign |
The correct way to increase volume is more mailboxes on more domains, each ramped properly. There is no configuration that produces more capacity faster, because the constraint is reputation and reputation only accumulates in real time.
Authentication#
SPF, DKIM and DMARC are checked before warmup begins and re-checked daily. Setup instructions with record examples are on connecting a mailbox.
Two additional things are worth doing once, on the domain, even though nothing in the console requires them:
- Use a separate outbound domain. A close variant of your primary. If outbound reputation goes wrong, it goes wrong somewhere that does not carry your invoices and your password resets.
- Age the domain before you use it. Register it, point it at a real page, and leave it for a few weeks. Domains registered days before their first campaign are treated with suspicion by every filter in the chain.
# Confirm one SPF record, and that it still includes your provider
dig +short TXT yourdomain.com | grep spf1
# Confirm DMARC is published and read the aggregate reports it sends you
dig +short TXT _dmarc.yourdomain.com
# Confirm the sending IP has a PTR record, if you self-host
dig +short -x 203.0.113.24List hygiene#
Bounces are the fastest way to damage a domain, and they are almost entirely preventable.
| Practice | Effect |
|---|---|
| Verify addresses before the first send | Removes the majority of hard bounces before they exist |
| Never send to catch-all domains without verification | Catch-alls accept everything and then bounce later, or complain |
| Never send to role addresses | info@, sales@ and support@ complain at high rates and reach nobody who decides anything |
| Cap per recipient domain | Three messages per company per day, so one company never receives a burst |
| Honour suppression permanently | Suppression survives re-qualification, campaign deletion and list changes |
The campaign-level bounce threshold is 3% over a rolling window, and crossing it halts the campaign and requires a human to restart it. See bounces and suppression.
Content patterns that cost you#
Message generation already avoids these. They matter if you are editing drafts, which you should be.
| Pattern | Problem | Instead |
|---|---|---|
| Images in a first message | A cold message with images is structurally unlike a person-to-person email | Plain text |
| Attachments | Attachments from unknown senders are filtered aggressively | Describe it; send it when they ask |
| Multiple links | Link density is a strong filter feature | One link at most, and preferably none in the first message |
| Unsubscribe language in a one-to-one message | Bulk-mail markers in a message claiming to be personal | A plain sentence offering to stop, in your own words |
| HTML signatures with tracking or social icons | Remote images and third-party hosts again | A three-line plain-text signature |
| Long messages | Length correlates with being ignored, not with being persuasive | Under 120 words in the first message |
What the system will not do#
Some of these are standard features elsewhere. They are absent here deliberately, and they are not configurable.
- No open or click tracking by default — for the reason at the top of this page.
- No tracking pixels on any message, ever. Even where click tracking is enabled for a campaign, no image beacon is inserted.
- No sending from a shared IP pool. Your mailbox, your domain, your reputation.
- No warmup pools or reciprocal mail networks.
- No sending outside the send window, including to clear a backlog.
- No unsubscribe stripping. Where an unsubscribe mechanism is legally required for a recipient’s jurisdiction, it is included and cannot be removed.
- No sending to an address that has ever opted out, from any campaign, in this workspace.
Next: the API, if you want the decisions somewhere other than the console. The setting referenced throughout this page lives in Settings → Sending identity.