Being in some warmup pools silently hurts your deliverability.

Trusting your warmup score by itself is a mistake — only a 3rd party can prove if you're at risk.

We don't grade our own paper for a reason. Warm.ac is the 3rd party: public, free, live.

6+ million domains

Warmup ≠ warming

Deliverability problems you could not explain, until now. 3rd party analysis of 4 sequencers' warmup.

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This is huge.

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This is huge.

We'll be back soon.

Industry composition ≠ Your composition

Your sequencer may place you in a very different pool than the industry average.

Public Data

Public data

Sampled from our own mailboxes, cross-referenced against 6M+ tracked domains — every major sequencer in one place.

  • Pool composition: Google, Microsoft, SMTP
  • Bounce rate per pool
  • Pool quality trends, week over week
Explore the public index
Private Data

Personalize data

Your own warmup, measured directly.
Our analysis begins where you're currently shown 100% warmup health.

  • Your specific sub-pool composition
  • Your real Google representation
  • Pool drift alerts when it moves

Getting your data from warm.ac
will always be free.

Warmup ≠ warming

Deliverability problems you could not explain, until now. 3rd party analysis of 4 sequencers' warmup.

Go to section:

  1. 01

    The dip you couldn't explain

  2. 02

    How warmup actually works

  3. 03

    How cold email got here

  4. 04

    The consequence

  5. 05

    Why the industry misses it

  6. 06

    The proof

  7. 07

    The industry is responding

  8. 08

    This gets solved together

  9. 09

    What to do

  10. 10

    The bottom line

This is huge.

We'll be back soon.