Connect Claude over MCP

The InboxValid MCP server lets Claude verify emails, find addresses, audit domains and clean lists on your account, from a chat. It runs at https://mcp.inboxvalid.com/mcp and works with any client that can send a request header.

Before You Start

1. Create an API key on the API page of your dashboard. It starts with iv_live_.
2. API keys work on paid plans, during an active giveaway, or when API access is turned on for your account. A key from any other account is refused.
3. Every check the connector runs is charged to your account exactly as the same check from the API or the dashboard.

InboxValid is not listed in the Claude connector directory yet, so you add it yourself as a custom connector. It takes about two minutes.

Add It in Claude on the Web or Desktop

On a Pro or Max plan, or a Free plan (one custom connector):

1. Open Customize, then Connectors.
2. Click + Add, then Add custom connector.
3. Name it InboxValid, paste https://mcp.inboxvalid.com/mcp as the server URL, and click Continue.
4. Set Authentication to No sign in.
5. Under Request headers, add the name Authorization with the value Bearer iv_live_your_key, then click Add.

On a Team or Enterprise plan, an owner adds it once under Organization settings, Connectors, Add, Custom, Web, with the same URL and header. Each member then opens Customize, Connectors and clicks Connect.

In a chat, click +, open Connectors and switch InboxValid on. Claude's own steps are in its custom connector guide.

Add It in Claude Code

Run this once, with your own key:

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

To share the setup with a team without committing a key, put this in the project's .mcp.json and have each person set INBOXVALID_API_KEY in their own environment:

{
  "mcpServers": {
    "inboxvalid": {
      "type": "http",
      "url": "https://mcp.inboxvalid.com/mcp",
      "headers": { "Authorization": "Bearer ${INBOXVALID_API_KEY}" }
    }
  }
}

Run /mcp inside Claude Code to confirm InboxValid shows as connected.

What Claude Can Do With It

• Verify: one address with its status, sub status and trust score, or a handful in one go.
• Find: a person's address from their name and company domain, a domain's address pattern, or a batch of people.
• Audit: a sending domain's MX, SPF, DKIM, DMARC, PTR and blocklist standing, and whether it meets the Gmail, Yahoo and Microsoft bulk-sender rules.
• Clean lists: estimate a list, create and confirm a bulk job, wait for it, read or export the results.
• Account: your credit balance, usage, ledger and recent activity.

Prompts that work well:

• "Verify sales@example.com and tell me if it is safe to send to."
• "Find the email for Jane Doe at example.com."
• "Clean these 300 addresses and give me only the ones to keep."

Ask Claude to estimate a list first: the estimate is free and compares the credits the list needs with your balance. Results carry the same fields as the API.

ChatGPT

ChatGPT connects to MCP servers through a sign-in flow rather than an API key, so the key-based setup above does not work there yet. Use Claude or the API until ChatGPT support is ready.

Troubleshooting

• Claude cannot connect, or Claude Code shows a 401: the Authorization header is missing or misspelled. The value must be Bearer, a space, then your key.
• A tool answers that the API key was rejected: the key was revoked or mistyped. Create a new one on the API page and update the header.
• A tool says the organization is suspended: check that the account has API access (see Before You Start). If it does, contact support.
• Not enough credits: top up on the billing page, then ask Claude to retry.

Still stuck? Contact support from your dashboard, or read the rest of the Product Guide.