InboxWarm.ai vs WarmupHero

InboxWarm.ai automatically warms Gmail, Outlook, and SMTP inboxes to build sender reputation, improve inbox placement, and reduce spam placement. It sends, opens, and replies to warmup messages using contextual replies generated by large language models and human-like sending patterns. InboxWarm describes its seed network as private and made up of real inboxes. Its spam recovery feature marks warmup messages as not spam and moves them to the primary inbox when they land in spam. Supported setups include Gmail, Outlook, SendGrid, Amazon SES, Mailgun, Yahoo, and custom SMTP/IMAP. Plans include SPF, DKIM, and DMARC domain-health monitoring and real-time inbox-placement tracking. Every plan includes a public REST API with 30 endpoints; the default rate limit is 20 requests per minute per API key. Monthly prices range from $15 a month for one mailbox to $5 a month for 51–100 mailboxes, with up to 100 warmup emails per inbox per day on those listed tiers. A 10-day trial covers one email account without a credit card.

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.