InboxWarm.ai vs Mailwarmup

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.

Mailwarmup is a web service that aims to raise sender reputation by generating positive email engagement through a shared network of more than 10,000 inboxes. After users connect an account using SMTP and IMAP details, it sends scheduled messages on their behalf. Network inboxes open and reply to messages, mark them important, and remove them from spam. A dashboard tracks warmup results, including messages removed from spam, categories, and email deliverability. Listed integrations include Gmail, Outlook, and SMTP; users can control sending and limits. Other listed tools include a Mail Health Score, blacklist monitoring, delivery statistics, blacklist removal prompts, and AI ramp ups in beta. Warmup messages can be filtered into a separate folder using the subject keyword “WUA.” There is no free plan, but a 7-day trial is offered. Starter costs $19 a month for one email account and up to 50 positive engagements per day. Growth is $49 a month for three accounts and up to 50 engagements daily; Scale is $99 a month for eight accounts and up to 100 daily; Powerhouse is $149 a month for eight accounts and up to 300 daily. Warmup does not guarantee inbox placement.