Resend vs Substack MCP Server
Resend is an MCP server published by resend. Marketplaces we read that list it: 1 (Docker MCP Catalog). Substack MCP Server is an MCP server published by conorbronsdon. Marketplaces we read that list it: 2 (Official MCP Registry, Community GitHub marketplaces). As of our marketplace pass on 2026-10-13. This pair was picked by a reader, not by our comparison rule, so search engines are asked not to index the page.
Where each is published
| Marketplace |  Resend |  Substack MCP Server |
|---|---|---|
| Docker MCP Catalog | Listed Version: sha256:2a786579214e Forks (GitHub): 91 Pulls (Docker Hub): 21 822 Stars (Docker Hub): 5 Stars (GitHub): 576 Not marked · First seen |
Not listed |
| Official MCP Registry | Not listed | Listed Version: 1.3.0 Downloads/month (npm): 1 991 Downloads/week (npm): 290 Forks (GitHub): 9 Stars (GitHub): 43 Not marked · First seen |
Each figure is the marketplace's own and is never added up across marketplaces. A marketplace that publishes no figure shows none: no number is not zero.
The facts side by side
| Fact | Resend | Substack MCP Server |
|---|---|---|
| Marketplaces that list it (differs) | 1 (worse) | 2 (better) |
| Stars (GitHub) (differs) | 576 (better) | 43 (worse) |
| Pulls (Docker Hub) (differs) | 21 822 | No figure on Docker Hub |
| Forks (GitHub) (differs) | 91 (better) | 9 (worse) |
| Last release | Not published | Not published |
| Where it runs (differs) | On your machine (mcp/resend) | On your machine (@conorbronsdon/substack-mcp) |
| Transport | stdio | stdio |
| Tools it declares (differs) | 1 | Not published |
| Environment variables it asks for | 3, secrets among them: 1 | 3, secrets among them: 1 |
| Parts of the bundle (differs) | Not a bundle | 2 |
| Licence | MIT | MIT |
| Repository (differs) | github.com/resend/mcp-send-email | github.com/conorbronsdon/substack-mcp |
| Changes in the last 7 days (differs) | 0 | 2 |
| First seen | 2026-10-11 | 2026-10-11 |
Lines where the two differ have a tinted background and bold values. Where the data itself says which value is better (more marketplaces, a larger figure of the same marketplace, a fresher release, a verified mark on a marketplace that lists both), the better one is also marked green with ▲ and the worse one red with ▼. Where it runs, the transport, the tools, the settings, hooks, the bundle's parts, the licence and the week's changes are marked only as different: more or fewer is not better in itself.
What each says it does
Resend
The official MCP server to send emails and interact with Resend.
Substack MCP Server
Substack drafts, Notes, analytics and consented subscribers. Long-form posts stay draft-only.
How to run each
Resend As a local MCP server: Docker image
claude mcp add --env "RESEND_API_KEY=<YOUR_RESEND_API_KEY>" --transport stdio resend -- docker run -i --rm -e RESEND_API_KEY mcp/resendRequires: RESEND_API_KEY (secret)
Substack MCP Server As a local MCP server: npm package
claude mcp add --env "SUBSTACK_PUBLICATION_URL=<YOUR_SUBSTACK_PUBLICATION_URL>" --env "SUBSTACK_SESSION_TOKEN=<YOUR_SUBSTACK_SESSION_TOKEN>" --env "SUBSTACK_USER_ID=<YOUR_SUBSTACK_USER_ID>" --transport stdio substack-mcp -- npx -y @conorbronsdon/substack-mcpRequires: SUBSTACK_PUBLICATION_URL, SUBSTACK_SESSION_TOKEN (secret), SUBSTACK_USER_ID
Commands built only from what the marketplaces declare; the full set for every client is on each card.
Tools each declares
The marketplaces of Substack MCP Server publish no list of tools, so we do not compare tools.
Settings each asks for
Only Resend asks for
REPLY_TO_EMAIL_ADDRESSESRESEND_API_KEY (secret)SENDER_EMAIL_ADDRESS
Only Substack MCP Server asks for
MCP_TRANSPORTSUBSTACK_PUBLICATION_URLSUBSTACK_SESSION_TOKEN (secret)SUBSTACK_USER_ID
Settings as each marketplace publishes them. Asking for fewer is not better in itself.
What it can do: Resend · What it can do: Substack MCP Server · Compare two other plugins
Data comes from the Docker MCP Catalog (desktop.docker.com/mcp/catalog) and Docker Hub. Data comes from the Official MCP Registry (registry.modelcontextprotocol.io), CC0 1.0. Data comes from public marketplace files in GitHub repositories of their authors. Figures come from our own regular passes over the marketplaces, last read on . We publish no contact details for plugin publishers.