.com is the safest choice for cold email, with the best default reputation with every spam filter, and .co, .net, and .org are close behind. Those four are the TLDs Winnr registers in the Classic purchase flow, and the Subdomain Strategy wizard offers them too. The premium low-abuse extensions .io, .sh, .vc, and .to are available only through the Subdomain Strategy. Cheap, bulk-registered TLDs like .xyz, .top, and .info aren't registrable through Winnr at all, because filters treat them with suspicion by default.
Classic purchase flow (the four Winnr registers)
.com: the gold standard. Every filter treats .com as neutral or better. Use it for anything.
.co: a common alternative with growing commercial use and good default reputation. Use it as a .com backup or when the .com is taken.
.net: old and stable. Solid for cold email.
.org: historically nonprofits, but widely accepted. Slightly unusual for commercial outreach.
All four are a one-time purchase, with the price shown in the search results.
Premium TLDs (Subdomain Strategy only)
.io, .sh, .vc, .to: low-abuse extensions with good reputation and a tech-leaning feel. They aren't sold in the Classic flow. They're offered in the Subdomain Strategy wizard, where you buy one domain and put up to 5 subdomains under it. They cost more per domain than the standard four. The Subdomain Strategy wizard also offers .com, .net, .org, and .co, so you don't have to pick a premium extension to use it.
Not registrable through Winnr
.ai, .app, .dev, .xyz, .top, .info, .club, .site, .online, .live, .space: Winnr doesn't register these. The cheap ones are mass-registered by spammers, so filters treat them as suspicious by default, and even a warmed, well-authenticated domain on one of them underperforms a fresh .com. The pricier ones (.ai) simply aren't part of the supported set.
Country codes for regions you don't operate in (.ru, .cn, .ir, .kp): universal red flags, and not registrable through Winnr anyway.
The pattern behind the rankings
Spam filters use TLD as a heuristic because spammers churn through domains on TLDs that are cheap or unrestricted. So:
- Cheap TLDs = spammer-heavy = filter-suspicious.
- Legacy TLDs (.com, .net, .org) = mixed use, no strong signal, so filters rely on other data.
- Restricted-registration TLDs (such as .bank, which requires a banking license) = spammer-scarce = filter-neutral.
The right move for most senders is to stick with .com (or .co/.net/.org). That's why Winnr only registers the legacy TLDs plus a small set of well-behaved premium ones.
What's next
- Buy a domain
- Subdomain Strategy: fewer domains, subdomains under each
- Aged vs new domains: does age matter?
Frequently asked questions
Does the TLD really matter for deliverability?
Yes, but it's a secondary factor. Authentication (SPF, DKIM, DMARC), sender reputation, and sending patterns matter more. That said, an all-else-equal .xyz domain gets filtered more aggressively than an all-else-equal .com.
Can I register .app, .dev, or .ai through Winnr?
No. The Classic purchase flow registers .com, .co, .net, and .org, and the Subdomain Strategy adds the premium .io, .sh, .vc, and .to. Everything else (.ai, .app, .dev, .xyz, and so on) isn't offered.
Can I use a domain with another extension that I already own?
Yes. Connecting a domain you already own isn't limited to these extensions, and neither is converting a domain to the Subdomain Strategy. The list above only covers what Winnr will register for you.
Country TLDs (.co, .io, .to, .sh). Are those risky?
The ones Winnr offers (.co, plus .io, .sh, .to via the Subdomain Strategy) are widely used commercially and have good reputation. Country TLDs from some regions (for example .ru or .cn) have poor reputation for cold email regardless of your actual business location, and aren't registrable through Winnr anyway.
What do the domains cost?
Every domain is a one-time cost, and each search result shows its price before you select it. Premium extensions (.io, .sh, .vc, .to) cost more per domain than the standard four.
Should I pay extra for a premium-name .com?
Not for cold email. Short, premium .com names can cost hundreds or thousands of dollars and offer no deliverability advantage over an ordinary .com. Spend that money on more ordinary domains instead.