ColdSire

Maildoso provides outbound mailboxes built for cold email, combining SMTP and Google Workspace infrastructure, fast setup, strong deliverability, and automated technical configuration. It helps teams diversify their sending strategy with reputable mailboxes built specifically for cold outreach, so campaigns are not dependent on one sender type, domain, or provider. Users can register domains directly in the dashboard or connect their own, enter mailbox names, and have SPF, DKIM, and DMARC auto-configured so mailboxes are ready to export and use with outreach platforms in minutes. Maildoso supports SMTP mailboxes, Google Workspace mailboxes, and combined setups, giving teams flexibility based on their sending strategy and target audience. It connects with popular sequencers and outreach tools such as Instantly, Smartlead, Saleshandy, and others, making it easier to move newly created mailboxes into active campaigns.

Winnr is a cold email infrastructure platform that runs the full sending stack in one place. Teams register outreach domains inside the dashboard, generate SMTP mailboxes that come with DKIM, SPF, and DMARC records already published, and enroll them in automated warmup. A shared inbox aggregates replies across every mailbox, and credentials export in one click to sequencers such as Smartlead or Instantly. Agencies and resellers can provision infrastructure programmatically through the REST API and webhooks. Continuous deliverability monitoring surfaces DNS drift and blacklist issues before they affect campaigns. Compared with running dozens of Google Workspace inboxes, Winnr cuts cost dramatically and reduces setup from days to minutes.