OpenMail vs Sendmux Sdk
A side-by-side look at the OpenMail and Sendmux Sdk MCP servers: transport, auth, tools, quality signals, and the config to install either one in Claude, Cursor, Windsurf or VS Code.
O
OpenMailCommunicationGmail for agents: create inboxes, read and reply to mail, send email, manage domains. OAuth sign-in.36FairAuth: oauth 2.0Verdict: choose OpenMail for communication work; choose Sendmux Sdk for communication as a local process. You can also run both side by side in one mcpServers block.
Which MCP server should you choose?
OChoose OpenMail when
- You need dedicated capabilities in the Communication domain.
- Its auth model fits you: OAuth 2.0.
- You have the keys it needs:
OPENMAIL_API_URL, MCP_RESOURCE_URL, MCP_JWT_SECRET, CONSOLE_ORIGIN, PORT, POSTHOG_API_KEY, MCP_ANALYTICS_DEBUG.
Choose Sendmux Sdk when
- You need dedicated capabilities in the Communication domain.
- You prefer a local stdio subprocess transport.
- Its auth model fits you: OAuth 2.0.
Feature & specification comparison
Rows where the two servers differ are marked.
| Spec | O OpenMail | |
|---|---|---|
| Category | Communication | Communication |
| Quality signal | 36/100 · Fair | 47/100 · Fair |
| Install command | Not confirmed yet | Confirmed |
| Transport | — | Local subprocess (stdio) |
| Auth | OAuth 2.0 | OAuth 2.0 |
| Pricing | Free | Freemium |
| Required env vars | OPENMAIL_API_URLMCP_RESOURCE_URLMCP_JWT_SECRETCONSOLE_ORIGINPORT |
Tools & capabilities
OpenMail tools
No tool names declared yet. Check the project README from the listing page.
Sendmux Sdk tools
No tool names declared yet. Check the project README from the listing page.
Ready-to-paste client configs
Paste either block (or both) into your client config, e.g. claude_desktop_config.json or ~/.cursor/mcp.json. We only show a config when the install command is confirmed.
OpenMail
No confirmed install command for OpenMail yet — follow the setup steps linked from its listing page rather than a guessed package name.
Sendmux Sdk
{
"mcpServers": {
"sendmux-sendmux-sdk": {
"command": "uvx",
"args": [
"sendmux-core"
]
}
}
}
Frequently asked questions
OpenMail is categorized under Communication and uses an install path we have not confirmed yet. Sendmux Sdk belongs to Communication and uses a local stdio subprocess. Pick OpenMail for communication work and Sendmux Sdk for communication.
Copy the mcpServers block from the config section on this page into your client's config (for example claude_desktop_config.json or ~/.cursor/mcp.json), then fully restart the client. OpenMail has no confirmed install command yet — follow its own setup instructions.
OpenMail is listed as free. Auth: oauth 2.0. Sendmux Sdk is listed as freemium — a free tier with paid plans. Auth: oauth 2.0. If a server needs environment variables such as API keys, define them under the env key in your client's MCP config.
Yes. MCP clients support multiple servers: add openmail and sendmux-sendmux-sdk as separate keys in the same mcpServers object, and your assistant will call tools from either one.
On AllMCPs, OpenMail has a quality signal of 36/100 (Fair) with 0 views, 0 installs and 0 GitHub stars. Sendmux Sdk has 47/100 (Fair) with 2 views, 0 installs and 65 GitHub stars.