Newsletter Insights — independent newsletter & sponsorship data across 42K+ newsletters
Browse all →
An open magazine of essays, ideas, and letters to the world. Written by many, read by all.
Enter your email and we'll send your inquiry to the Newsletter Insights team.
Tell us your brand and audience. We send back 10-15 newsletters matched to your brief, with sponsor history and CPM ranges per placement.
$300·2-3 working days·refunded if we can't deliver
See what's includedThe Open Letters's metrics, benchmarks, and sponsor data in one document
56K
Top 10% in Uncategorized
substack
Uncategorized
+4.0%
vs 0% category avg
0.13%· ~74/post
(comments + likes) / subscribers
vs 0.00% category avg
~3x per week
2.5 posts/week avg
vs 1.0/week category avg
Free
Category avg: $5/mo
20202
newsletters in Uncategorized
Top 10% in Uncategorized
out of 20202 newslettersPublishing Frequency
~3x per week
Last published Oct 12, 2026
Usually publishes Mon, Sat
2.5 posts/week avg