InboxPlan vs Mailwarmup

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.

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.