Productivity · Official remote MCP server

The x402 Format Checker MCP server,
connected in one click.

IBAN, EU VAT, NIP, REGON, PESEL, email checks. Only $0.001 (0.1 cent) per check via x402 on Base. Connect the official x402 Format Checker MCP server to Claude, ChatGPT, or Cursor through gate — one gateway URL, no config files, security-checked.

Connect x402 Format Checker free How it works

Free to start · No credit card · No hosting needed

Use this server

Add x402 Format Checker to your AI in one minute

Pick your client. Copy, paste, done — or let gate handle sign-ins and policies for you.

claude mcp add --transport http x402-format-checker https://validate.crewofthecaptain.com/mcp

Run in your terminal, then restart Claude Code.

x402 Format Checker · https://validate.crewofthecaptain.com/mcp

What you can do

What your AI can do with x402 Format Checker

Real prompts you can type the moment it's connected — no setup, no docs to read.

“Use “list_types”: List the available checks, price, network and payment details (free). Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.”

“Use “validate_iban”: IBAN: country length + ISO 13616 mod-97 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, nor.”

“Use “validate_eu_vat”: EU VAT number: per-country format (offline, no VIES); PL also NIP checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.”

“Use “validate_pl_nip”: Polish NIP tax id: 10 digits + weighted mod-11 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, val.”

Security check

How secure is the x402 Format Checker MCP server?

Every server in the gate directory has to pass the same four checks before your AI can touch it. Here's how x402 Format Checker holds up.

✓ Verified directory serverx402 Format Checker · crewofthecaptain.com

Official endpoint

Operated by x402 Format Checker (crewofthecaptain.com) at its documented MCP endpoint — not a third-party mirror or community re-host.

No sign-in needed

This server only exposes public data — no account and no credentials are involved when you connect.

Scanned before it goes live

gate checks every tool for prompt injection, hidden instructions, data-exfiltration hints, and over-broad permissions before the server is available through your gateway.

Watched for drift

If x402 Format Checker adds or changes tools later, gate re-scans and alerts you — before your AI acts on the change.

Run the free scanner on x402 Format Checker's server →

How it works

Connected in three steps

Connect your gate

Add one gateway URL to Claude, ChatGPT, or any MCP client. One-time setup, about two minutes.

Pick x402 Format Checker

Choose x402 Format Checker in the gate directory. No sign-in needed.

Use it anywhere

x402 Format Checker's tools are live in every AI client you've connected — with rules and logging built in.

Connect x402 Format Checker free

Free to start · No credit card · No hosting needed

Straight from the server

The actual tools x402 Format Checker exposes

Fetched live from the official endpoint and re-checked daily by gate — not marketing copy.

list_types — List the available checks, price, network and payment details (free). Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.

validate_iban — IBAN: country length + ISO 13616 mod-97 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, nor

validate_eu_vat — EU VAT number: per-country format (offline, no VIES); PL also NIP checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.

validate_pl_nip — Polish NIP tax id: 10 digits + weighted mod-11 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, val

validate_pl_regon — Polish REGON: 9 or 14 digits + mod-11 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, norma

validate_pl_pesel — Polish PESEL: checksum + encoded birth date and sex. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid,

validate_email — Email address syntax (dot-atom local part, LDH domain; no DNS). Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {ty

Author

Who runs the x402 Format Checker MCP server?

crewofthecaptain.com

Homepage More servers from crewofthecaptain.com →

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Server facts

The x402 Format Checker MCP server at a glance

Endpointhttps://validate.crewofthecaptain.com/mcp

Operated byx402 Format Checker (crewofthecaptain.com)

CategoryProductivity

Sign-inNone — public data only

Available in gateYes — one-click connect

Works withClaude, ChatGPT, Cursor & any MCP client

FAQ

Questions, answered

Is there an official x402 Format Checker MCP server?

Yes — x402 Format Checker operates its own remote MCP server at validate.crewofthecaptain.com. gate connects you to that official endpoint and adds security scanning, per-tool access rules, and an activity log on top.

How do I connect x402 Format Checker to Claude or ChatGPT?

Add gate's gateway URL to your AI client once, then pick x402 Format Checker in the directory. No account or sign-in is needed. From then on, x402 Format Checker's tools are available in every client you've connected to gate.

Do I need to host anything?

No. x402 Format Checker runs the server, and gate is fully managed. You just connect one URL — there's nothing to install, deploy, or maintain.

Is the x402 Format Checker MCP server safe to connect?

It's the vendor's official endpoint, and gate scans its tools for prompt injection and hidden instructions before it goes live, re-checks it whenever it changes, and lets you allow, block, or require approval for every single tool.