Land in the inbox.Not the spam folder.

The main difference is isolation. Many cold email platforms send from shared IP pools, so one customer's spam complaints can hurt everyone else's inbox placement. Sendbox gives every customer dedicated IPs on isolated sending infrastructure, and each mailbox stays pinned to its IP. Your reputation is built by your own sending and nobody else's. Those tools have strengths of their own, and our comparison pages cover where each one fits.

Warmup starts automatically when you connect a mailbox. You set the starting volume, how fast it ramps each day, the target volume, and reply-rate goals, and Sendbox runs it in the background. Warmup is unlimited on every plan under fair use, so you never have to choose which mailboxes are worth warming.

Every mailbox shows its live status along with reply and bounce rates. SPF, DKIM, and DMARC records are checked for each domain, and blacklist monitoring and inbox placement tests are included on every plan. When a mailbox or domain starts to slip, you see it before a whole campaign fails, so you can pull it from rotation and let warmup rebuild it.

Setup is fully self-serve, with no mandatory onboarding call. Connect mailboxes over Gmail or Outlook OAuth or IMAP/SMTP, upload a lead CSV (fields map and addresses are validated on import), write your sequence, and launch. Brand-new mailboxes should ramp up through warmup before sending at full volume, and Sendbox handles that ramp for you.

Google Workspace and Gmail, Microsoft 365 and Outlook, and any provider that supports IMAP/SMTP. There is no cap on how many mailboxes you connect. ESP matching checks each lead's provider and sends from a matching mailbox where it can, which improves the odds of landing in the inbox.

Sendbox sends signed webhooks to any HTTP endpoint for events like lead.created, lead.added, lead.replied, lead.bounced, email.sent, and email.opened. That lets you push replies and leads into your CRM or automation tool of choice, including Zapier, Make, or n8n, without waiting on a native integration.

Yes. Workspaces keep each client's mailboxes, leads, and campaigns separate, from 3 workspaces on Growth up to unlimited on Enterprise. White label is included from the Scale plan, and custom branded client reports from the Fleet plan. Your agency's sending also runs on its own isolated infrastructure, so other Sendbox customers can't affect your clients' reputation.

Mailbox warmup, email validation, inbox placement tests, and blacklist monitoring are unlimited on every plan, subject to the fair use limits in our Fair Usage Policy. The caps that change between plans are monthly sending volume, lead storage, and workspaces.

Sendbox has five plans: Launch, Growth, Scale, Fleet, and Enterprise. They scale by monthly email volume, from 75,000 emails and 30,000 stored leads on Launch to 10 million emails on Enterprise. There is no per-seat pricing and no extra charge per mailbox. Dedicated IPs, isolated infrastructure, unlimited warmup, the AI reply agent, and the unified inbox are included on every plan.

Yes. Every step in a sequence can carry multiple variants. You set the minimum sends and days before it acts, and Sendbox shifts volume toward the winner and pauses the underperformers automatically, so campaigns improve while they run without anyone watching the numbers.