Emaillistchecker.io MCP server — email verification for AI agents
Remote Model Context Protocol server that tells an AI agent whether an email address can receive mail before anything is sent to it.
The server is hosted; there is nothing to install. This repository documents how to connect.
Get a key (no account needed)
Connect without a key and call the get_api_key tool, or:
curl -X POST https://platform.emaillistchecker.io/agent-gateway/register \
-H 'Content-Type: application/json' \
-d '{"name":"my-agent","purpose":"verify signup emails"}'
The key is shown once. Each key gets 25 free verifications per day (unused credits do not roll over) and expires after 30 days; register again when it does. Send it as Authorization: Bearer <api_key>.
Connect
Claude Code
claude mcp add --transport http emaillistchecker https://platform.emaillistchecker.io/mcp --header "Authorization: Bearer YOUR_KEY"
Claude Desktop / Cursor / VS Code (mcp.json-style config)
{
"mcpServers": {
"emaillistchecker": {
"type": "http",
"url": "https://platform.emaillistchecker.io/mcp",
"headers": { "Authorization": "Bearer YOUR_KEY" }
}
}
}
| Tool | What it does |
|---|
get_api_key | Get a free key (works without a key) |
verify_email | Verify one address → valid, invalid, risky or unknown (1 credit) |
verify_batch | Verify up to 25 addresses per call, with per-address verdicts |
get_batch_status, list_lists, get_list | Follow saved verification lists |
explain_result | Explain a verdict in plain English, with a send recommendation |
estimate_cost, get_credit_balance | Check credits before running |
Verdicts
valid: the mailbox exists and accepts mailinvalid: the address or domain cannot receive mailrisky: accept-all (catch-all) domain, role or disposable address, or a Microsoft 365 address the mail server couldn't confirmunknown: the receiving server gave no definitive answer
Limits
10 requests per minute per key, one request in flight per key, and a shared daily capacity for free agent keys (HTTP 429 until 00:00 UTC when it is used up). Inbox placement, blacklist monitoring and email finder need a full account at https://www.emaillistchecker.io.
REST API
The same key works on the REST API: POST https://platform.emaillistchecker.io/api/v1/verify, POST https://platform.emaillistchecker.io/api/v1/verify/batch, GET https://platform.emaillistchecker.io/api/v1/credits. See the OpenAPI description.