MailStrike vs WarmupHero

MailStrike is an email deliverability platform for mailbox warming, placement testing, and seed lists for B2C senders. AI personas create and reply to email threads using a company's description and industry. Its warming network exchanges threads among business mailboxes while excluding spammers, free-mail senders, and dodgy sites. On connection, the service checks SPF, DKIM, DMARC, and MX records and identifies missing values. Google Workspace and Microsoft 365 connect through OAuth; other providers use IMAP and SMTP with an app password. Warming reaches full volume by day 21 and then continues at a maintenance volume. Seed lists monitor placement and can interact with messages; setup requires one DNS TXT record for domain verification. A free deliverability test reports inbox, promotions, or spam placement and scores spam signals without requiring a card. MailStrike runs on the web and through an API. Paid plans start at $18/mo (annual); there is no free plan, but a free trial is available.

WarmupHero is an email warmup service that gradually increases sending volume to build an address’s reputation and reduce spam risk. It says setup takes one minute, works with all email service providers and runs automatically. The service exchanges warm-up messages with real people, sends personalized emails sequentially and keeps messages in conversation threads with automated replies. It opens warm-up emails, marks them important and moves them back to the inbox when they land in spam. Analytics show whether messages reach the inbox, spam or folders such as Promotions and Updates. Users can customize messages and add signatures containing images or links. Connections include the Office365 API and an SMTP/IMAP method for other business accounts. SmartReach.io users generate an API key before connecting an email account. WarmupHero is available as a web service and extension, with spam monitoring listed. Its free SmartReach.io plan costs nothing. The privacy policy says it does not access, read or delete users’ emails, while it may process information supplied about recipients and customers.