Stackblade and Reletter
Reletter is a search engine for newsletters on every platform, built for sponsors and outreach. Stackblade only covers Substack and keeps a daily record of it. If you buy ads on many platforms or need contact details, Reletter does more. If you want to see whether a Substack writer is growing before you pay them, the history is here, and most of it is free.
| Reletter | Stackblade | |
|---|---|---|
| Price | $49 a month (100 searches, 1 user), $99 (500 searches, 5 users), $199 (unlimited searches, 10 users). API add-on $59 a month. 7-day trial; a card is required to start. | Pages free. Pro $12 once. |
| Newsletters covered | More than seven million, on Substack, LinkedIn, Ghost, Beehiiv and Kit | Substack only: every writer on a category board (6,000+) and anyone looked up |
| Subscriber numbers | Listed as a feature | Substack's rounded count and paid band, free. Exact numbers where the writer verified and chose to share. |
| History | Not described on its site | Followers every 3 days (daily when watched), every board daily, from Oct 31, 2026 |
| Recommendations | Not described on its site | Who recommends whom, with Substack's start dates, and the network chart |
| Growth over time | Not described on its site | 7-day and 30-day change (from Nov 7 and Nov 30, 2026), rank moves, new recommenders |
| Contact details | Yes, including email addresses | No |
| Traffic and engagement | Traffic estimates | Open rate and conversion only where writers verified and shared them |
| Alerts and exports | Alerts, exports, lists | Pro: watchlist of 100, digests to Discord, Telegram, webhook, RSS; CSV of any writer or view |
Reletter's prices and plan limits are from reletter.com/pricing, and its coverage and features from reletter.com, checked Nov 6, 2026. "Not described on its site" means the page doesn't mention it, not that the product lacks it. If anything changes, tell me and I'll update this page.
Moving a list over
Export a list from Reletter, or copy a column of URLs from any spreadsheet, and paste it into the import box in your dashboard. I pick out every substack.com address, custom domain I know, and @handle, match them to writers I track, and add them to your watchlist. Anything I don't track is listed so you can look it up.
When to use which
- Buying a sponsorship in one Substack newsletter: look the writer up here first. Check the follower trend, rank history, who recommends them, and whether they verified their numbers. A checklist.
- Prospecting across Beehiiv, Ghost, Kit and Substack, or needing emails for outreach: Reletter.
- Watching a set of Substack newsletters over months: Stackblade Pro.