Mailcheck MCP server
2 operations0 webhooks
Email verification API for validating email addresses and email domains.
Try Mailcheck with your agent
Connect Mailcheck, then paste this into Claude, ChatGPT or Cursor. For ideas from other apps, see the use cases.
Using Corsair, show me what you can do in Mailcheck on my account, then run one read-only example and show me the result.
Mailcheck tools and triggers
Tools are what your agent can do in Mailcheck through Corsair's MCP server. Triggers are the Mailcheck events a routine can start from.
Domain
- ValidateRead-only
Check a domain for MX records, disposable providers, and catch-all mail
domain.validate
- VerifyRead-only
Verify an email for syntax, MX records, and SMTP validity
email.verify
Connect Mailcheck to Claude, ChatGPT or Cursor
- 1
Connect Mailcheck in Corsair
Add your Mailcheck API key once in Corsair. Corsair stores the credential encrypted and makes the Mailcheck API calls for your agent, so it never goes into a prompt or a config file. Connect Mailcheck
If your link lets the agent add apps, you can skip this: it gives you a sign-in link the first time it needs Mailcheck. On a ChatGPT personal plan, connect Mailcheck here first.
- 2
Add Corsair's MCP server to your agent
Every client uses the same address:
https://mcp.corsair.dev/mcpOpen Customize → Connectors → Add custom connector, paste the address, then select Connect.Add a custom MCP server with the address and choose OAuth. Personal plans get read tools only.Add to CursorOr add this to~/.cursor/mcp.json. Cursor opens Corsair to sign in the first time it connects.{ "mcpServers": { "corsair": { "url": "https://mcp.corsair.dev/mcp" } } }Run this, then run/mcpin Claude Code to sign in.claude mcp add --transport http corsair https://mcp.corsair.dev/mcpCodex, Gemini CLI, VS Code, Zed and other clients with OAuth sign-in work the same way. Clients without it, such as GitHub Copilot's coding agent, use a link's own address and an API key. Setup for every client
- 3
Sign in and choose what needs your approval
Your client opens Corsair to sign in. Pick a link: the apps your agent can use and a mode that decides what it may do without asking. Every Mailcheck operation only reads data, so it runs right away in every mode.
FAQ
Install corsair and @corsair-dev/mailcheck, add the Mailcheck plugin, and connect with an API key. Then call methods like corsair.mailcheck.api.domain.validate() from your app. Corsair keeps each tenant isolated.
Yes. Mailcheck requires an API key from your Mailcheck account or developer dashboard. Create credentials with access that matches what you automate, then paste them into Corsair or connect through managed auth in Hub.
Yes. One Corsair client can hit Mailcheck, GitHub, Notion, Stripe, and the rest. Trigger Mailcheck from a webhook, push updates to Slack, or chain actions across plugins. Same tenant context across integrations, plain TypeScript.
Teams use Corsair for email verification api for validating email addresses and email domains. Common builds include sync jobs, admin tooling, and agents that call Mailcheck APIs from your backend.
The SDK is open source. Self-host and you pay Corsair nothing for the integration layer. Hub bills for hosted auth and execution, not per Mailcheck API call. Hub has a generous free tier. For hobby projects you can probably run the whole thing on free. Paid plans start to matter with more tenants or heavier traffic.
We maintain @corsair-dev/mailcheck in the open repo. When Mailcheck ships API changes, upgrade the package. Your call sites stay typed. You should not need to rewrite the integration layer each time.
No. Corsair does not read your Mailcheck data or hold individual access credentials. Credentials stay in your database. API calls run on your instance. We do not store Mailcheck data on your behalf.
Yes. Add https://mcp.corsair.dev/mcp as a custom connector or MCP server in Claude, ChatGPT, Cursor, VS Code, Claude Code, Codex or any client that supports remote MCP servers with OAuth sign-in, then sign in to Corsair. On ChatGPT personal plans, custom servers currently get read tools only.
Yes. Put Mailcheck on a link in Strict mode and every write waits for your approval, while destructive actions are refused. Every Mailcheck operation only reads data, so there are no changes to approve today. You can change a link's mode at hub.corsair.dev/me.