SignupBouncer MCP Server

by signupbouncer Your server? Claim it

answering

SignupBouncer is answering right now. Last checked 3 min ago. It exposes 4 tools.

An API that checks new signups for disposable emails and repeat accounts.

Uptime history 15 hours of history

15 hours agonow

100.0%

Uptime 24h

53 of 53 checks

Tools

read from the server

403 ms

Response time

average over 24h

open, no key

Access

streamable-http

Nothing serious here today

Today is the operative word: we check SignupBouncer every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 3 min ago.

Claude Code Claude Desktop Codex Cursor VS Code

run in your terminal

claude mcp add checker --transport http https://signupbouncer.com/mcp

~/Library/Application Support/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "checker": {
      "url": "https://signupbouncer.com/mcp"
    }
  }
}

~/.codex/config.toml

[mcp_servers.checker]
url = "https://signupbouncer.com/mcp"

.cursor/mcp.json

{
  "mcpServers": {
    "checker": {
      "url": "https://signupbouncer.com/mcp"
    }
  }
}

.vscode/mcp.json

{
  "mcpServers": {
    "checker": {
      "url": "https://signupbouncer.com/mcp"
    }
  }
}

Available tools 4

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

check_email

Checks one email address, and optionally the signup's IP address, the way SignupBouncer checks a new signup. Returns the result as "verdict" (allow, challenge or block), a 0-100 score, the reasons with their reason codes, the normalised inbox (Gmail dots and +tags folded) and the IP's network. When the domain looks like a typo of a big mail provider (gmial.com), "suggestion" holds the corrected address. Looks up the domain's mail servers live. Every reason is listed, including ones only paid plans count. Nothing sent is stored.

explain

explain_reason

Explains a SignupBouncer reason code (for example disposable_domain, burner_mx, repeat_inbox, datacenter_ip): what it means, how many points it adds or whether it blocks alone, and the lowest plan on which it counts. Without a code, lists every code.

integration

integration_guide

Returns the steps and the copy-paste code that checks new signups with SignupBouncer in one stack: supabase (a hook, no code), fetch (any TypeScript server), nextjs, express, hono, python, firebase or better-auth. Use it when the user is building or changing a signup, register or auth flow. The code reads the API key from SIGNUPBOUNCER_API_KEY. The call has a 1.5-second limit, and any failure lets the signup through.

lookup

lookup_burner_domain

Says whether a domain is on SignupBouncer's disposable (burner) email list, a known relay service or a free subdomain mail service, or a known real mailbox provider, and when our harvester observed it. Uses only the loaded lists, no DNS lookup, so a brand-new burner domain on a burner mail server is caught only by check_email. Accepts a domain or an email address.

Endpoints

URL	Transport	State	Latency	Checked
https://signupbouncer.com/mcp	streamable-http	answering	415 ms	3 min ago

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SignupBouncer — questions

Answers built from our own checks of this server.

What can SignupBouncer do?

It exposes 4 tools, read directly from the server on our last check. Among them: check_email, explain_reason, integration_guide, lookup_burner_domain. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →

Is SignupBouncer working right now?

We send a real MCP handshake every 15 minutes. Over the last 24 hours 53 of 53 checks got a reply (100.0%), average response time 403 ms. The bar chart above shows every period we have measured.

How do I connect SignupBouncer?

Copy the ready config from this page — we generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each with the file path that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.

Does SignupBouncer need an API key?

No. SignupBouncer completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 4 of them are readable on this page. This is what we observed, not what the docs claim.

How fast is SignupBouncer?

It answers our handshake in 403 ms on average, which is faster than 30% of all working MCP servers we measure. The comparison comes from our own checks across the whole registry, every 15 minutes.