InboxPlan vs InboxWarm.ai

InboxPlan is a web service for automated email warm-up, scheduling, and deliverability monitoring. It creates warm-up messages and simulated two-way conversations tailored to a user's industry, then schedules activity with randomized send windows and a gradual increase in volume. InboxPlan says sending typically starts at 3–5 emails per day in week one and reaches 30–50 per day by week four; users can set manual limits for each account. A live monitor tracks sender score, inbox placement, and spam rates across major providers. Users can connect Gmail, Outlook, Zoho, or custom SMTP accounts and warm multiple mailboxes in one workspace, subject to the plan's account allowance. Each account receives its own threads, schedule, and reputation dashboard. InboxPlan says it uses OAuth and does not store account passwords. It names sales teams, agencies, and startups among its intended users, as well as businesses in SaaS, recruiting, real estate, finance, and e-commerce. The service is paid, with no free plan, and offers a 7-day free trial that requires a credit card. InboxPlan was founded in 2022 and is headquartered in San Francisco, California.

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.