InboxPlan vs MailStrike

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.

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.