Warm up your SendGrid inbox and stop sending cold emails to spam.
Improve the deliverability of your cold email campaigns through SendGrid. Warmup Inbox builds your sender reputation across major mailbox providers — automatically.
Why warm up your SendGrid inbox?
SendGrid is a fast, reliable way to send email at scale. But sending cold outbound through SendGrid without a warmed sender reputation lands you in spam — same as any other provider. Warmup Inbox builds the reputation that gets your messages to the inbox.
Cold SendGrid sending hits spam
Mailbox providers don't care about SendGrid's reputation — they care about yours. New senders or sudden volume spikes through SendGrid trigger spam filters fast.
Warmup builds sender trust
Real inboxes exchange real conversations with your SendGrid sender. Reputation builds gradually with Gmail, Outlook, and Yahoo — so your campaigns land where they should.
What will you love about us?
Simplicity
The tool is easy to use. Setup takes minutes, not days. Support is one message away if you get stuck.
No fake inboxes
Unlike many other services, we use real inboxes that communicate with each other. The automation never affects user inboxes.
Fair price
Email warmup doesn't have to break the budget. Plans start at $15/inbox/mo annually. No unnecessary fees, no feature lock-ins.
Connect SendGrid in 30 seconds
API key, three steps, you're warming.
Paste your SendGrid API key
Generate a SendGrid API key with mail-send permissions and paste it into the connect screen. We handle the rest.
Activate warmup
One click. Reputation starts building from day one across Gmail, Outlook, Yahoo, and more.
Frequently asked questions
Can I use SendGrid for cold email?
Yes — SendGrid supports cold outbound, but you need to warm your sender reputation first. Without warmup, mailbox providers flag sudden cold-email volume as spam regardless of which sending service routes it.
How do I connect SendGrid to Warmup Inbox?
Generate a SendGrid API key with mail-send permissions, paste it into the Warmup Inbox connect screen, and activate. Setup takes under 30 seconds. No DNS changes required.
Does this work with SendGrid's dedicated IP add-on?
Yes. Dedicated IPs benefit even more from warmup since you're building reputation on a fresh IP from scratch. We pace volume gradually to match SendGrid's recommended ramp-up curve.
Will Warmup Inbox affect my SendGrid send quota?
Warmup messages count against your SendGrid send volume. Most plans send 75–1,000 warmup messages per inbox per day depending on your Warmup Inbox tier. Plan your SendGrid quota accordingly.
How long until I see deliverability improvements?
Most teams see open-rate and inbox-placement lift within 14–21 days. Brand-new SendGrid sender domains take 30–45 days for full warmup maturity.
Stop sending SendGrid emails to spam
Warm your sender reputation in minutes. Your campaigns reach the inbox; your team gets back to closing.