Email Verification MCP Server for Claude

Connect Claude to CampaignKit and you can verify emails from a chat: paste an address or a list of leads, and Claude checks them with our email verification MCP server and tells you which ones are safe to send to.

What the CampaignKit MCP server gives Claude

CampaignKit's email validation MCP server is a remote MCP server at https://api.campaignkit.cc/v1/mcp/sse. We built and run it ourselves; it doesn't go through Zapier, n8n or another vendor's API. Claude reaches it by URL with your CampaignKit API key, and so can other clients that support remote MCP servers. It is not made, listed or endorsed by Anthropic: you add it to Claude yourself, as you would any custom MCP server.

What you can ask Claude to do

You can verify emails with Claude in plain language. Some prompts that work well, and the tool Claude uses for each:

• Check one address before outreach: "Is alice@example.com a valid email?" Claude calls validate_email.
• Validate a pasted list of leads: "I have 20 emails from a lead magnet. Can you validate them?" Claude calls create_validation_job with the list.
• Follow a job and read the results: "What's the status of validation job #123?" and "Show me the invalid addresses from that job." Claude calls get_job_status, then get_job_results.
• Review your numbers: "Show me my validation statistics for the last 30 days." Claude calls get_validation_stats.
• Check a sign-up address in a support chat: "A customer says they never got our emails. Can you check customer@example.com?" Claude calls validate_email.

The five tools

Tool	What it does	Credits
validate_email	Validates one email address and returns its score and classifier.	1 per validation
create_validation_job	Starts a batch job for a list of addresses, with an optional label.	1 per email, charged during processing
get_job_status	Shows a job's state (pending, running, done, failed or paused) and a summary of deliverable, undeliverable and risky addresses.	Free
get_job_results	Returns a job's results, 50 per page. Claude can ask for the next page.	Free
get_validation_stats	Shows your account's validation stats for the last 7 days by default, up to 365 days.	Free

The MCP server reference lists every parameter and response field.

Set up the email verification MCP server in Claude

Setup takes a few minutes:

1. Create an API key. Sign in to the CampaignKit app, go to Settings → API Keys and click Create New API Key. Copy the key; it starts with ck_. Keep it private, like a password.
2. Add the server to Claude. Add the server URL https://api.campaignkit.cc/v1/mcp/sse to your MCP client, and send your key as a Bearer token in the Authorization header (Bearer ck_…).
3. Restart or reconnect. Restart Claude Desktop, or reconnect the server in your client, so it loads the new server.
4. Test it. Ask Claude: "Can you validate the email address test@example.com?" If Claude replies with a score and a classifier, you're connected.

For the exact configuration and troubleshooting, follow the Claude AI integration guide.

What you get back

Every address comes back with a score from 0 to 10 and a classifier. Claude puts them into a plain answer. For example:

You: Can you check if john.doe@company.com is valid?

Claude: The email john.doe@company.com has a score of 10/10 and is classified as "valid".

How to read the score:

Score	Meaning
10	Fully verified: the mailbox exists.
9	Valid, but the mailbox couldn't be confirmed.
2	Usable but risky.
0	Will bounce.

The classifier is valid (deliverable), risky or invalid (will bounce). A mailbox can't always be confirmed, so some real addresses score 9 rather than 10. Risky addresses need your judgment: review them before you send, or send to them with care.

Typo suggestions. When an address fails and its domain looks like a well-known provider, the result includes a suggestion. For john@gmai.com, which scores 0 and is invalid, the suggestion is john@gmail.com. When no suggestion applies, there is none. Show the suggestion to the person who entered the address instead of rewriting it silently.

For a batch job, Claude can summarize the job and then list the results page by page. Treat the numbers in any example conversation as examples; your results depend on your list.

How it compares to other email MCP servers

Other email verification MCP servers exist. Some run as a local process on your machine; others are hosted connectors from third-party platforms. As of October 2026, from each project's listing or README:

	CampaignKit	MCP Email Verify	BounceProtect
Where it runs	Hosted by CampaignKit, reached by URL	Locally, set up on your machine	Locally, as a STDIO server
What you supply	A CampaignKit API key	Python 3.11+, UV and your own AbstractAPI key	Your own BounceProtect API key
Bulk checks	Batch jobs with status and paged results	None listed in its README	validate_emails_bulk, up to 100 addresses
Free credits	200 validations	Not stated	100 credits

A local server can suit you if you want to run everything on your own machine. Platforms such as Composio also host connectors for other verification services: you add their connector URL to Claude, then authorize the service. Check each project's page for current details.

Pricing

Every new account gets 200 free validations, no credit card required. After that, you pay as you go from $6 for 2,500 emails ($2.40 per 1,000), with no subscription, and credits never expire.

Through Claude, each validation costs 1 credit, and batch jobs charge 1 credit per email during processing. Checking a job's status, reading results and viewing stats are free. Credits are only deducted for addresses with valid syntax. If your credits run out, Claude gets an "insufficient credits" error, and you can top up in the app. See pricing for all packs.

More ways to verify emails

• Follow the Claude AI setup guide to connect the server.
• Read the MCP server documentation for every tool and field.
• Use the email validation API from your own code, or see everything for developers in one place.
• Check a single address without Claude in our free email verifier.
• Automate validation without code with CampaignKit for Zapier.
• Read about how we handle data on our security page and in our data processing agreement.

Claude is a trademark of Anthropic. CampaignKit is not affiliated with or endorsed by Anthropic.