Warmupinbox

What is Warmupinbox?

Warmupinbox is an automated email warmup tool that improves your sender reputation by connecting your inbox (Gmail, Outlook, Google Workspace, or any SMTP) to a network of 30,000+ real human inboxes. These inboxes open, reply, and mark your emails as not spam, teaching spam filters that your domain is legitimate. This helps land your emails in the Primary inbox instead of Spam.

Problem it solves

Cold email senders often struggle with poor deliverability — emails landing in spam or promotions. Warmupinbox solves this by building a positive sender reputation over time, reducing bounce rates and improving inbox placement. It also monitors 100+ blacklists and automatically initiates rescue if you get listed, helping you get delisted faster.

Who is it for?

Warmupinbox is ideal for sales teams, marketers, agencies, and recruiters who rely on cold email campaigns. It's also useful for lifecycle teams sending regular emails to customers. It's not designed for transactional email senders or those looking for a full email marketing platform.

Real use cases

Sales teams warm up new domains before outreach; marketers ensure newsletters hit Primary; agencies manage warmup for multiple clients; recruiters improve response rates on cold outreach. With 2x faster warmup than other tools, expect results in as few as 3 days.

• Real Inbox Network — 30,000+ real human inboxes provide genuine opens and replies, improving sender reputation naturally.
• Blacklist Rescue — Automatic monitoring of 100+ blacklists and rescue actions when listed, reducing downtime.
• Spam & Category Monitoring — Track inbox placement across providers to see if you land in Primary, Promotions, or Spam.
• Language Warmup — Train your sender reputation for specific languages (Pro plan).
• Custom Settings — Control warmup messages, topics, and schedules (Pro plan).
• API Access — Integrate warmup data into your own tools (Pro and Max plans).