If you don't know what to set, use this page. Use these settings on every new mailbox. Your results depend on your domain's existing reputation, so adjust based on your spam rate and inbox placement tests.
You only need three things to get running
1. Add a mailbox → 2. Start warm-up → 3. Choose your settings (this page).
Everything else in this reference is optional.
Check the content type for each endpoint
The emails-per-day, response-rate, ramp-up and sending-schedule endpoints use
application/x-www-form-urlencoded: send fields with-din cURL, not-F. The warm-up audience endpoints take a JSON body. (The connect endpoints are different again — those usemultipart/form-dataand-F.)
At a glance
| Setting | API field | Recommended |
|---|---|---|
| Emails per day — Google and Microsoft | email_per_day | Match your daily cold volume 1:1 (25 cold = 25 warm-up). Not sending cold yet: start at 25. Recommended max 50. |
| Emails per day — custom SMTP (Winnr, Maildoso, others) | email_per_day | Up to 2× your cold volume — check with your SMTP provider first. When in doubt, 1:1 is always safe. |
| Response rate | response_rate | 35 to 40%. Raise it toward 55% only if your spam rate starts climbing. |
| Ramp-up | rampup_speed | On, set to fast (about 14 days), for any mailbox a few months old or newer, or with no warm-up or sending history. |
| Warm-up audience | warmup_audience_type | all — business and consumer (the default). |
| Sending schedule | sending_schedule_preset | Weekdays - 8am to 6pm in the mailbox owner's timezone. |
| Custom templates | Custom Warm-Up Templates | Optional for most senders. Add the copy you actually send if you're in a regulated industry like finance or insurance. |
| Blacklist monitoring | Blacklist Monitoring | On for every domain you send from. |
| Inbox placement test | IPT - Tests | Run one before your first campaign, then regularly. |
Emails per day
Match your daily cold volume 1:1. If you send 25 cold emails a day from a mailbox, set warm-up to 25. Not sending cold yet? Start at 25.
| Mailbox | Recommended | Recommended maximum |
|---|---|---|
| Google / Microsoft | 1:1 with your cold volume | 50 per day |
| Custom SMTP (Winnr, Maildoso, others) | 1:1 with your cold volume | Up to 2× your cold volume — check with your SMTP provider first |
Microsoft mailboxes usually send fewer cold emails, so their warm-up comes out lower too. A Google or Microsoft mailbox sending 200 cold emails a day should still stay at 50 — warm-up volume is there to establish a sending pattern that looks like your real one, not to maximise raw volume.
curl -X PATCH https://app.mailivery.io/api/v1/campaigns/$CAMPAIGN_ID/update-email-per-day \
-H "Authorization: Bearer $MAILIVERY_API_KEY" \
-d "email_per_day=25"
Check your account pool first
Emails per day is drawn from an account-wide pool, not allocated per mailbox. Twenty mailboxes at 50/day each needs a plan covering 1,000/day. Check what you have before you provision:
curl -X GET https://app.mailivery.io/api/v1/account/limits \
-H "Authorization: Bearer $MAILIVERY_API_KEY"
{
"data": {
"email_per_day": { "total": 310, "used": 26, "available": 284 },
"email_accounts": 15,
"email_accounts_need_attention": 5,
"emails_sent_today": 0
}
}
If you set a per-mailbox value that exceeds what's available, the request is capped by your account allowance.
Response rate
Response rate is the percentage of your warm-up emails that get a reply from the Mailivery network — 25 warm-ups at 40% = 10 replies a day.
Set it to 35 to 40%. Raise it toward 55% only if your spam rate starts climbing.
curl -X PATCH https://app.mailivery.io/api/v1/campaigns/$CAMPAIGN_ID/update-response-rate \
-H "Authorization: Bearer $MAILIVERY_API_KEY" \
-d "response_rate=40"
Response rate only changes how many replies a mailbox's warm-up emails receive. Those replies come in to the mailbox, so they don't use any of its emails-per-day or your account's daily allowance.
Relayed sending caveat
If a mailbox's SMTP and IMAP email addresses do not match (for example, relayed sending), Mailivery treats the response rate as 0 regardless of what you set — replies can't be reliably routed back to the original sender.
Ramp-up
Ramp-up starts warm-up at low volume and raises it daily until it reaches your target. Turn it on, set to fast (about 14 days), for any mailbox a few months old or newer, or with no warm-up or sending history.
Set it at connect time with with_rampup and rampup_speed, or enable it later. rampup_speed is required:
curl -X PATCH https://app.mailivery.io/api/v1/campaigns/$CAMPAIGN_ID/enable-ramp-up \
-H "Authorization: Bearer $MAILIVERY_API_KEY" \
-d "rampup_speed=fast"
rampup_speed | Reaches your target in about | |
|---|---|---|
fast | 14 sending days | Recommended |
normal | 30 sending days | Used when you turn on with_rampup at connect time without choosing a speed |
slow | 60 sending days |
Only days your sending schedule sends on count, so with a weekdays-only schedule the climb takes longer on the calendar.
Warm-up audience
Which inboxes receive your warm-up: business, consumer or both.
Use all — business and consumer. It's the default. Choose business only if you only email B2B, or consumer only if you only email personal addresses.
Set it for the whole team with Update Team Warm-Up Audience Preference, override a single mailbox with Update Mailbox Warm-Up Audience Preference, or pass warmup_audience_type when you connect the mailbox. These endpoints take JSON:
curl -X PATCH https://app.mailivery.io/api/v1/team/preferences/warmup-audience \
-H "Authorization: Bearer $MAILIVERY_API_KEY" \
-H "Content-Type: application/json" \
-d '{"warmup_audience_type": "all"}'
Sending schedule
Warm-up that sends at 3am every day doesn't look like a person. Pick the preset that matches how the mailbox owner actually works:
curl -X PATCH https://app.mailivery.io/api/v1/campaigns/$CAMPAIGN_ID/update-sending-schedule \
-H "Authorization: Bearer $MAILIVERY_API_KEY" \
-d "sending_schedule_preset=Weekdays - 8am to 6pm" \
-d "timezone=America/Chicago"
| Preset | |
|---|---|
Weekdays - 8am to 6pm | Standard business hours — the safe default |
Weekdays - 7am to 7pm | Longer working day |
Weekdays - 6am to 10pm | Widest weekday window |
With Weekends - 8am to 6pm | Include Saturday and Sunday |
With Weekends - 7am to 7pm | |
With Weekends - 6am to 10pm |
On the connect endpoints the same setting is named
sending_schedule_presets(plural). On this endpoint it issending_schedule_preset(singular).
Optional extras
None of these are required to run warm-up.
| What it does | Recommended | |
|---|---|---|
| Custom Warm-Up Templates | Your own email copy, mixed into your warm-up | Optional for most senders. Add the copy you actually send if you're in a regulated industry like finance or insurance. |
| Blacklist Monitoring | Alerts you if a domain or IP lands on a major blocklist | On for every domain you send from. Monitors count against your plan's monitor allowance. |
| Inbox Placement Test | Shows where your email lands at each provider: inbox, spam or promotions | Run one before your first campaign, then regularly. Included in all plans. |
By provider
The settings above apply to every provider, except the recommended emails-per-day ceiling, which is higher for custom SMTP. What also differs is how you connect the mailbox in the first place:
| Provider | Connect with | Notes |
|---|---|---|
| Google Workspace / Gmail | Connect a Google Mailbox (App Password) | Requires 2-Step Verification on the account and a 16-character app password. |
| Google Workspace / Gmail | Connect a Google Mailbox (OAuth) | Mailbox owner authorizes via Google consent — no app password. |
| Microsoft 365 / Outlook | Connect a Microsoft Mailbox | Returns a Microsoft consent URL. The mailbox stays pending until the owner completes consent — call Start Warm-Up after that. |
| Custom SMTP | Connect Mailbox with SMTP | Needs full SMTP and IMAP host, port, username and password. |
| Any of the above | Get Secure Embed Form URL | Hosted form — your users authorize without you handling credentials. |
Next step
Once settings are in place, confirm the mailbox is healthy with Get Health Score, and watch Get Metrics over the first week.
Need help with your settings? Book a free deliverability audit from the Mailivery sidebar.