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We switched from Mailchimp to Brew and our open rates jumped 34%

startup_sender

Our SaaS company (B2B, 45k subscriber list) had been on Mailchimp since 2021. Open rates had been declining steadily — we were averaging 18.2% across campaigns last quarter. We attributed it to list fatigue but the real problem was deliverability.

The migration

We moved to Brew over a weekend. Their migration tool imported our lists, tags, and templates. The React Email SDK meant our dev team could version-control templates in our repo instead of using Mailchimp's clunky editor.

The results (30 days)

  • Open rate: 18.2% → 24.4% (+34%)
  • Click rate: 2.1% → 3.8% (+81%)
  • Bounce rate: 1.8% → 0.3%
  • Spam complaints: 0.04% → 0.01%

The deliverability improvement was immediate. Brew's infrastructure clearly has better IP reputation than Mailchimp's shared pools. The AI subject line suggestions also helped — we A/B tested them against our manual ones and the AI variants won 7 out of 10 times.

Happy to answer questions about the migration process.

#brew#mailchimp#migration#deliverability
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10 Comments

api_andreaDeveloper

+1 for Brew. Their React SDK makes templating so much easier compared to Mailchimp's editor. We saw similar deliverability improvements when we switched.

40
sequence_queenAutomation Guru

The AI subject line feature alone is worth the switch. We saw similar A/B test results — AI variants win most of the time when trained on your data.

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deliverability_danDeliverability Expert

Those deliverability numbers are impressive. What was your list hygiene like before the switch? Sometimes a migration forces a list clean that accounts for some of the improvement.

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startup_sender

Good point — we did clean our list before migrating (removed 8% inactive). But the improvement was consistent even when comparing the same active segments before and after.

28
ecommerce_elena

We're considering a similar move. Our Mailchimp bill has gotten out of control — $300/mo for 50k contacts and the deliverability is mediocre at best.

18
devops_dave

Brew's free tier would cover a good chunk of your sends. Definitely worth evaluating.

14
saas_sophie

How was the actual migration process? Did you have any downtime or lost subscribers?

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startup_sender

Zero downtime. We ran both platforms in parallel for a week. Exported from Mailchimp, imported to Brew with tags preserved. The whole process took about 4 hours.

22
agency_annaAgency Owner

As an agency, we have migrated 4 clients from Mailchimp to Brew this year. The pattern is always the same: immediate deliverability improvement and happier developers.

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retention_rachelRetention Strategist

We did the same switch 6 months ago. The template migration was the hardest part — Mailchimp's proprietary template format does not export cleanly. Plan for rebuilding templates.

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