Black Friday lands on Friday, November 27, 2026, 22 days from now. When your emails end up in spam while your sending tool shows everything green, the deliverability causes sit in your sending infrastructure and your list, well before the volume curve.
This guide sets a calendar through November 30, with the action to take on each date and the metric that tells you whether it worked. The thresholds cited come from Google and Microsoft documentation.
Freeze your infrastructure this week
No new IP and no new sending subdomain should appear in November. Google treats as new any domain that has not exceeded 5,000 messages per day to personal Gmail accounts since January 1, 2024. Google applies an accelerated enforcement schedule to it (Google sender guidelines FAQ). A sending address opened on November 12 therefore falls under the least forgiving regime at the worst possible moment.
Warming up an IP or a domain is covered in our email warm-up guide. You can’t catch it up in three weeks.
Check the reverse DNS of every sending IP: dig -x 203.0.113.10 must return a hostname that points back to that same IP, which Google requires from bulk senders. The reverse DNS lookup guide has the details. A failure shows up as the SMTP error 550 5.7.25.
Also take stock of what leaves from each IP. A transactional message (order confirmation, invoice) sent from the same IP as your promotions suffers the same rejections. For the duration of the period, keep the two streams on separate IPs so the messages that must arrive at all costs stay protected.
What Gmail and Outlook require from 5,000 messages per day
Google applies its rules to senders who send close to 5,000 messages or more per day to personal Gmail accounts: SPF and DKIM on the sending domain, a published DMARC record (a p=none policy is enough) with the From domain aligned to SPF or DKIM, TLS for transmission, and one-click unsubscribe on marketing messages (Google sender guidelines, in effect since February 1, 2024).
One-click unsubscribe relies on the List-Unsubscribe and List-Unsubscribe-Post headers, detailed in the article on the List-Unsubscribe header. Google recommends processing each request within 48 hours. During Black Friday, the previous day’s unsubscribe queue must therefore be empty before the next day’s send.
Microsoft sets the same threshold of 5,000 emails per day for Outlook.com. Since May 5, 2025, SPF and DKIM must pass and DMARC must exist at a minimum of p=none with alignment. Non-compliant messages go to junk first, then may be rejected with the code 550 5.7.515, according to the post published by the Microsoft Defender for Office 365 team (April 2025). That post specifies that the safe senders list does not bypass these rules.
One last checkpoint is the compliance dashboard in Postmaster Tools v2, at postmaster.google.com/v2/sender_compliance. It compares your actual traffic against the guidelines above. The Google Postmaster setup guide covers creating the account and verifying the domain. Also check the record with dig TXT _dmarc.yourdomain.com: the response must start with v=DMARC1. Do it today, Thursday, November 5, because data that’s missing on November 26 is data you won’t have when you need to decide.
Verify the list before writing to old contacts
A Black Friday campaign often wakes up addresses that haven’t received anything in months. That’s where the hard bounce rate climbs, since some mailboxes have been closed in the meantime. Every permanent rejection counts against your sender reputation.
A common objection is that you only learn the bounce rate after the send, so why pay for verification first? Because the finding comes too late: the bounce is already recorded in the IP’s history by the time the report appears. Microsoft also lists regular list cleaning and bounce management among its best practices.
Two cases come up, depending on how old the contacts are.
- Contacts active over the past few months: re-verify them at the frequency described in How often should you check your email list?
- Dormant contacts: follow the protocol in resuming email campaigns after a long break, then the sorting logic in Emailing: what to do with inactive contacts?
A catch-all domain accepts any address during the SMTP conversation, so only a deferred bounce (soft bounce then NDR) reveals a nonexistent mailbox. Isolate these addresses in a separate segment.
Before the next campaign, run a sample of the dormant list through CaptainVerify verification. The invalid address rate you observe tells you how much of the list can reasonably go out on the 27th.
Ramp up volume in steps until November 27
Gmail lists “gradual increases in sending volume” among the checks a sender must pass for the unsubscribe link to appear at the top of the message (Google FAQ). A send that suddenly multiplies your usual volume strays from that profile. The right step depends on your history, so the calendar below doesn’t impose any volume. Increase in small steps from one send to the next.
- November 9 to 13: write only to contacts who have recently opened or clicked, at your usual pace.
- November 16 to 20: add the next segment, after a list verification done by the 14th at the latest.
- Monday, November 23: last big send before the 27th. In Gmail, open a received message, then More > Show original: the SPF, DKIM and DMARC lines must show PASS.
- November 27: the biggest volume of the period, sent to segments that have already been proven.
Monitor the week of November 23 to 30
The complaint rate remains the central metric. Google asks you to keep it under 0.1% and to avoid reaching 0.3% in Postmaster Tools. Since June 2024, above 0.3%, a bulk sender is no longer eligible for mitigation, and a rate above 0.1% already weighs on delivery. It only becomes eligible again after 7 consecutive days under that threshold (Google FAQ). A spike on Friday, November 27 therefore deprives you of that recourse until December 4 at the earliest, Cyber Monday on November 30 included.
The daily check includes four readings:
- Postmaster Tools: user-reported spam rate, updated every day.
- Sending tool logs, pulled at 9 a.m. and 5 p.m.: 5xx rejections (hard bounces) and 4xx deferrals, sorted by Enhanced Status Code.
- Microsoft rejections: any series of 550 5.7.515 signals an authentication failure, to be fixed before the next wave.
- IP reputation on Outlook: the Microsoft SNDS dashboard.
Microsoft’s 2025 post sets no complaint threshold. The 0.1% figure applies to Gmail. On the Outlook side, you steer from rejections and SNDS. If the IP is a shared pool with other customers of your router, these dashboards also reflect their behavior.
Set a decision rule before the 27th: if the complaint rate approaches 0.1% at midday, pause the least engaged segment and keep the recent customers. Make this decision today.
On December 1, export the addresses that generated permanent rejections during the week and remove them from the list. They must not end up in the first send of January.
