Terms

Last updated 29 September 2026.

prewarmed.org is operated by the team behind Warm Inboxes (warminboxes.com) and Upscale B2B (upscaleb2b.com). Orders are fulfilled by Warm Inboxes. Using this site means accepting what follows.

What this site is

prewarmed.org publishes research, comparisons and calculators about cold email infrastructure, and it sells nothing directly. Every order link sends you to Warm Inboxes, where the purchase happens under that company's terms. If those terms and these ever disagree about an order, theirs govern the order.

What we say about prices and specifications

Prices shown here are published from a single data file and are kept in step with Warm Inboxes deliberately, but the price you pay is the one shown at checkout there. Specifications — aging and warming periods, mailbox counts, delivery times — describe what is normally supplied and are not a warranty for any individual order.

What we do not promise

Nobody can guarantee inbox placement, and we do not. Infrastructure decides whether your mail gets a fair hearing; your list, your copy and your sending behaviour decide the rest. Figures on this site — recommended volumes, aging periods, the arithmetic in the calculators — are guidance drawn from operating this infrastructure, not a prediction of your results.

The free tools are provided as they are. Most of them run on warminboxes.com and are subject to that site's terms. Use their output as evidence, not as a verdict.

Using the site properly

You may read, quote and link to anything here. You may not scrape it wholesale, republish it as your own, or use it to build a competing directory. If you want to cite a figure, cite it and link back — that is encouraged.

Infrastructure bought through the links here must be used lawfully. That means honouring unsubscribe requests, sending to data you have a lawful basis to contact, and complying with the rules that apply where you and your recipients are — CAN-SPAM, GDPR and PECR among them. Cold email is legal in most places when done properly. Doing it improperly is your liability, not ours.

Affiliate and commercial relationships

Some outbound links on this site are commercial, including every link to Warm Inboxes, which is operated by the same team. Where a link to a third party earns a commission, that is disclosed on the page it appears on. It never changes what we write about a product.

Accuracy and corrections

We get things wrong sometimes. When a figure here is wrong, write to hello@prewarmed.org and we will correct it and say what changed rather than editing quietly. The method behind the numbers is on the methodology page.

Liability

To the extent the law allows, we are not liable for losses arising from decisions you make based on this site — including lost revenue, lost data, or damage to a sending domain. Nothing here excludes liability that cannot lawfully be excluded.

Changes

These terms can change. The date at the top shows when they last did.

Contact

hello@prewarmed.org. These terms are offered by Upscale Systems LLC, which operates prewarmed.org; the same address reaches them.