ListCheckup

ListCheckup MCP server

Email verification for AI assistants. Connect Claude, Cursor or any MCP client to ListCheckup and let it check a single address or a whole list, showing you the price before anything is spent.

• Endpoint: https://listcheckup.com/mcp (remote, Streamable HTTP)
• Auth: Authorization: Bearer lck_live_... (create a key in your ListCheckup dashboard)
• Free tier: 100 checks every month, no card. Catch-all and unknown results are not charged, and credits never expire.
• Data: processed on EU servers. Nothing is sent to the addresses being checked.

Tools

Tool	What it does	Cost
check_email	Verify one address: valid, invalid, risky, catch-all or unknown, with the reason and a confidence score	1 credit (free if catch-all or unknown)
get_balance	Credits left on the account	Free
create_list	Submit a list and get its price	Free
start_list	Start checking a list you've priced	Spends credits
get_list	Status and progress of a list	Free
get_list_summary	Counts by status once a list is finished	Free

Pricing and starting are separate tools on purpose: an assistant has to show you what a list will cost before anything is spent, and you can say no. No tool takes an account as an argument; the key in the header decides whose credits are used.

Connect

Claude Code

claude mcp add --transport http listcheckup https://listcheckup.com/mcp \
  --header "Authorization: Bearer lck_live_..."

Claude Desktop, Cursor and most other clients

{
  "mcpServers": {
    "listcheckup": {
      "url": "https://listcheckup.com/mcp",
      "headers": { "Authorization": "Bearer lck_live_..." }
    }
  }
}

Check it works

curl -X POST "https://listcheckup.com/mcp" \
  -H "Authorization: Bearer lck_live_..." \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}'

Six tools listed means you're connected.

Example prompts

• "Check whether [email protected] is a real address."
• "Here's my leads CSV. How much would it cost to verify it? Don't start until I say so."
• "How many credits do I have left?"

Treat the key as a password

Anything holding it can spend your credits. Keep config files with the key out of shared repositories, give each machine its own key, and revoke a key in the dashboard if it leaks. Revoking takes effect immediately.

Links

• REST API docs: https://listcheckup.com/api
• Verify emails in n8n: https://listcheckup.com/n8n-email-verification/
• Free email domain checker (MX, SPF, DMARC): https://listcheckup.com/email-domain-checker/

ListCheckup checks addresses you already hold. Purchased, rented or scraped lists aren't allowed under the acceptable use policy.