A new blocklist now flags domains warmed with fake engagement. See if your brand is exposed before Black Friday and what to do instead.
On September 3, Validity announced a blocklist called Heatwave aimed at domains whose sending reputation was manufactured. Its target is artificial warm-up: tools that trade fake opens, clicks and replies between networks of dummy inboxes so a new domain looks loved by mailbox providers.
Validity says more than a million domains have been listed so far. If your holiday email plan leans on a warmed-up domain, and you are not sure who warmed it, that is worth checking this week, not in the middle of Cyber Week.
What Heatwave actually flags
According to Validity, warm-up services connect to a customer's email tenant, register lookalike domains and generate synthetic messages, opens, clicks and replies among fake accounts. The goal is to feed false engagement signals to mailbox providers.
The signal is not stuck in one product. Validity says it is mirrored into its DNS reputation zones, and that Comcast, Proofpoint, Spamhaus, SURBL and email service providers use or are evaluating the list. Spamhaus CEO Carel Bitter is quoted calling synthetic engagement "another iteration of the same problem".
Why this can hit you even if you never bought warm-up
Validity points out that some senders may not know warming is happening under their name, because it can run through subcontracted or partner vendors. An outbound agency or a sales team's cold email tool can set it up without anyone in marketing seeing it.
Resend's follow-up on September 30 puts the risk bluntly: a warming listing is permanent, so a flagged domain may not recover. It also notes that a separate cold outreach classification can be removed once the outreach stops, but the warming listing stays.
Why the shortcut tempts so many teams
The pressure is understandable. A fresh domain has no history, so the first big send tends to land in spam or get throttled. Warm-up tools promise a fast route around that, and for a while the numbers on their dashboards look great.
The trouble is that the engagement is not coming from customers. It comes from a closed loop of fake accounts. Mailbox providers and security vendors are now sharing signals about exactly that pattern, and as Resend quotes, "If you rely on automation to simulate interest, inbox systems eventually detect that pattern."
Think about what that means commercially. You can spend weeks and a monthly fee building a reputation that looks healthy, then lose it in one listing right before the busiest sending weeks of the year. Slow and real beats fast and fragile.
A 15-minute check before your holiday calendar locks
Do this in order:
- Search your main sending domain at lookup.validity.tools. Results may also show related domains you did not know existed.
- Ask every agency, freelancer and sales tool owner whether any warm-up service touches a domain carrying your brand.
- List every domain and subdomain that sends marketing mail, then separate the promotional ones from the sales outreach ones.
- If anything is listed, read Validity's listing policy and request a review if you believe the listing is wrong.
- Pause any warm-up subscription you find until you know exactly what it does.
The boring rules still decide your inbox placement
Heatwave is new, but the basics Google set out for bulk senders have not moved. Google's sender guidelines apply to anyone sending more than 5,000 messages a day to Gmail accounts and require the following.
- SPF, DKIM and DMARC set up on the sending domain, with the From domain aligned.
- One-click unsubscribe, using both the List-Unsubscribe and List-Unsubscribe-Post headers, plus a visible link in the body.
- A spam rate below 0.30% in Postmaster Tools, with Google recommending you stay under 0.10%.
- Valid forward and reverse DNS records, and TLS for transmission.
Failing mail may be marked as spam or rejected with a 5.7.26 error. Heavy sales weeks are exactly when a small complaint problem becomes a big one, so look at your complaint rate before the volume goes up.
What to do instead of faking engagement
Resend's alternative is simple, if slower: verify your domain, collect proper consent, and raise sending volume gradually. Real engagement from real subscribers is the only reputation that survives a blocklist.
For a holiday push, that usually means sending first to your most engaged segments, then widening the audience in steps. A good email marketing programme already works this way. If your list is thin, lead nurture sequences and marketing automation can build engaged subscribers honestly instead of borrowing reputation.
The point of view: cold email and promotional email should not share a domain
My take is that the cheapest protection is separation. Keep sales outreach on its own domain so that anything that goes wrong there cannot touch the domain that carries receipts, newsletters and your Black Friday offer.
A listing on a secondary domain is an annoyance. A listing on your main brand domain can mean lost revenue in your biggest sales window, and the newest tooling is getting better at spotting shortcuts, not worse.
Key takeaways
- Validity's Heatwave blocklist, announced September 3, targets domains warmed with synthetic engagement and has listed more than a million.
- You can be exposed through an agency or vendor you forgot about, so check your domain now.
- The warming listing is permanent according to Resend, so prevention beats repair.
- Meet Google's bulk sender rules and keep spam complaints under 0.10% where you can.
- Separate cold outreach from promotional sending on different domains.
If you want a second pair of eyes on your sending setup before the holiday rush, get a free quote and we will look at it with you.
John Doe
Supreb Information. Thanks
15 July 2014 View replies . 1