Check out the best alternative tools you can use as a replacement for Mailwarm.
Mailwarm is an email warm up tool that improves sender reputation and email deliverability, ensuring your campaigns reach inboxes, get more responses, and convert better. Mailwarm supports email warm up for Gmail, Outlook, Yahoo, Zoho, and major email service providers, including SendGrid and other SMTP-based platforms.
Mailwarm supports a bunch of features including email warmup, spf validation, dkim validation, and more, so any alternative needs to provide similar feature sets.