Deliverability for new domains
Warm up your domain before your first real campaign
New domains land in spam because they have no sending history. WarmEnvelopes builds one for you — real emails from your domain, through your own Resend account, growing steadily, to inboxes you own.
The inbox is earned, not given
Mailbox providers judge senders on history. A new domain has none — and the rules got sharply stricter through 2025 and 2026.
89.8%
Gmail's average inbox placement — the best of the majors. Microsoft manages just 77.4%.
Inbox placement by provider →
~6 weeks
M3AAWG's average for building sender reputation on a new domain. It cannot be rushed.
How long warmup takes →
24 hours
Every newly registered domain spends its first day on the Spamhaus ZRD blocklist — before it sends anything.
Why new domains start blocked →
Tens of millions
Messages Gmail rejected within weeks during its November 2025 enforcement ramp — mostly over missing PTR records.
The PTR record problem →
How it works
Three steps, then the ramp runs by itself. Read the full mechanism →
Get a Resend API key
Warm-up mail is sent through your own Resend account. Create an API key there and keep it handy.
Configure a sending domain
Add a domain you own, paste the API key, and list the inboxes you control as recipients.
Start warming up
A scheduler sends a few emails a day and gradually increases the volume, building a natural sending history.
No fake engagement. No inbox network.
Most warmup tools log into a shared pool of inboxes and simulate opens, replies, and rescues from the spam folder. WarmEnvelopes doesn't. It sends real mail from your domain to inboxes you control, on a schedule that looks like a business slowly coming online — because that's what it is.
How this differs from warmup networks →Smart daily planning
Sending is spread across the day in small batches — no bursts that look like a script.
Real, human emails
A rotating library of 1,000+ natural-sounding messages in several languages keeps the traffic organic.
Full sending log
Every email is logged. Track progress per domain and filter the history by status and date.
Is your domain ready to send?
Check SPF, DKIM, DMARC, MX, and blocklist status in seconds — free, no sign-up, plain-English results.
Simple pricing
Free
€0
- 4 warm-up emails per day, per domain
- Up to 10 domains
- Full sending log
- No credit card required
Pro
€9/month
- Configurable ramp per domain
- Start 1–50 emails/day, grow by up to 50/day
- Scale up to 1,000 emails/day
- Cancel anytime
Frequently asked questions
What is domain warming?
Gradually increasing the volume of email sent from a domain so mailbox providers build a positive sending history for it. New domains have no history, and providers treat unknown senders with maximum suspicion — warming replaces that suspicion with a track record.
How long does warming up a domain take?
Plan for weeks, not days. M3AAWG — the industry body mailbox providers actually participate in — suggests considering six weeks as an average. Published ESP ramp schedules range from about three to eight weeks depending on target volume.
Resend says legitimate senders don't need warmup. Do I?
Resend's criticism targets warmup networks that fake engagement inside closed inbox pools — and on that point we agree. But Resend's own guidance lists gradual, consistent volume increases as a real deliverability signal, and Google's sender guidelines say to ramp up slowly and keep volumes consistent. That gradual ramp is exactly what WarmEnvelopes automates.
Is this one of those warmup networks that fakes opens and replies?
No. WarmEnvelopes sends real emails from your domain to inboxes you own — there is no shared inbox pool, no simulated opens, no fake replies. What we build is a genuine, gradually growing sending history.
What do I need to get started?
Three things: a domain you own, a Resend account with an API key (and your domain verified there), and at least one inbox you control to receive the warm-up mail. Sign-in is with Google.
How many emails does it send per day?
The free plan sends exactly 4 per day per domain. Pro (€9/month) lets you configure the ramp: start at 1–50 per day, increase by up to 50 per day, and cap anywhere up to 1,000 per day.
Will warmup guarantee my mail lands in the inbox?
No, and nobody can honestly promise that. Warmup builds sending history — one important input among several. You still need correct DNS (SPF, DKIM, DMARC, PTR), clean lists, and content people want. Our domain checker and guides cover the rest.
Can I warm up more than one domain?
Yes — up to 10 domains per account, each with its own Resend API key, recipients, and ramp schedule.
More questions? The deliverability guides go deep.
Ready to earn your way into the inbox?
Sign in with Google, connect a domain, and let the warm-up run in the background.
Get started for free