facts402: x402 API finder + fact checks

com.facts402Published by facts402.comv0.1.1Updated Nov 3, 2026

Find the right paid x402 API, plus fact checks: IBAN, EU VAT, OFAC sanctions, LEI, FX

The publisher's own server: Finder Jobs

VerifiedSTDIODesktop onlyWeb Search & ScrapingFinanceBusiness & Commerce

Overview

AI-generated overview

Local MCP server that finds paid x402 APIs and runs paid fact checks (IBAN, EU VAT, OFAC, LEI, FX, domain, weather) via USDC micropayments.

What you can do
  • Recommend and preview x402 endpoints for a described task, with price, network, buyer counts, liveness and risk flags
  • Validate identifiers: IBAN/BIC, EU VAT via VIES, phone numbers and email addresses
  • Screen names against the OFAC SDN sanctions list and look up companies in the GLEIF LEI index
  • Convert currencies at ECB reference rates and get domain registration facts via RDAP
  • Count business days and public holidays, fetch weather forecasts and sun times
  • Read raw on-chain facts for a Base ERC-20 token contract
When to use it
Useful when an agent needs small, exact answers it can rely on before paying out, invoicing, onboarding a company, screening a counterparty or doing outreach, or when it needs to pick which paid x402 API to call.
Requirements
Runs locally with uvx (Python/uv). A Base mainnet wallet private key in X402_PRIVATE_KEY holding USDC is needed for paid tools; without it only the free preview works. Optional caps X402_MAX_PER_CALL_USD (default 0.30) and X402_SESSION_BUDGET_USD (default 2.00). Network access required.
Before you install
Requires a wallet private key (X402_PRIVATE_KEY) that signs USDC payments; use a dedicated hot wallet with a small balance and keep the key out of version control. Calls spend real money: $0.005 for recommendations and $0.01 per fact check, capped per call and per session. Queries and identifiers are sent to facts402 and upstream sources such as VIES, GLEIF, OFAC, ECB and MET Norway.

Installation

In SourceWeft

  1. Open facts402: x402 API finder + fact checks in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

facts402-mcp

Find the right paid API for a task, and verified fact checks for AI agents. Before an agent pays an unknown API, x402_recommend ranks the x402 endpoints that fit the task by relevance, real on-chain buyers and liveness, for $0.005 (the preview is free). And at $0.01 per call: validate an IBAN before a payout. Check an EU VAT number in VIES before invoicing. Screen a name against OFAC sanctions. Look up a company's LEI. Validate a phone number or email before outreach. Convert currency at official ECB rates. Check how old a domain is. These are small, exact answers an agent can rely on, with no API keys or sign-up.

Pay per call with x402: USDC on Base, from your own wallet, within a per-call cap and a session budget you set.

Tools

ToolPrice (USDC)Use it to
x402_recommend$0.005Find the best paid x402 endpoints for a task: url, price, network, 30-day buyers, liveness, risk flags, score
x402_recommend_previewfreeSee the single top pick (host, price, buyers) for a task
iban_check$0.01Validate an IBAN and get bank name, BIC and SEPA membership
eu_vat_check$0.01Check an EU VAT number in VIES: status, company name and address
sanctions_screen$0.01Fuzzy-screen a person, company, vessel or aircraft against the OFAC SDN list
lei_lookup$0.01Look up a company in the GLEIF LEI index, by LEI or by name
phone_check$0.01Validate and normalise a phone number: E.164, line type, carrier, time zone
email_check$0.01Check email syntax, MX, disposable and role-account flags
fx_convert$0.01Convert currency at ECB reference rates, for the latest day or any of the last 90
domain_check$0.01Get a domain's age, registrar, status and DNSSEC via RDAP (WHOIS)
business_days$0.01Count business days and list public holidays between two dates
weather_forecast$0.01Get a forecast for any coordinates, up to 7 days
sun_times$0.01Get sunrise, sunset, golden hour and day length
base_token_check$0.01Get raw on-chain facts for a Base ERC-20 contract (owner, proxy, mint / pause / blacklist)

The service charges only for a successful (2xx) answer: invalid input, upstream errors and a recommend query with no match (404) are never charged. Recommendations use the x402-list.com catalog (CC BY 4.0) and sellers' own 402 quotes, filtered and re-scored by facts402; facts402's own APIs are ranked with the same formula. For Base memecoin trading safety (honeypot, rug pull, exit liquidity, smart money), see base-memecoin-guard-mcp.

Payments and limits

VariableDefaultMeaning
X402_PRIVATE_KEY(unset)Private key of a Base mainnet wallet you control that holds some USDC. Without it, x402_recommend_preview works and the paid tools return their price and setup steps, paying nothing.
X402_MAX_PER_CALL_USD0.30The most one call may pay.
X402_SESSION_BUDGET_USD2.00The most the server may spend until it restarts.
  • Use a dedicated hot wallet with a small balance. One dollar of USDC buys 100 checks or 200 recommendations.
  • No ETH is needed: x402 exact payments are gasless EIP-3009 USDC authorisations.
  • The key stays on your machine. It is never logged or returned, and it signs only the one request you made.
  • Payments go only to the facts402 receiving address (0x5498b0Aa90cd56F8962CBd136DF3D3769C85f149). A quote for any other payee, any other token or a Permit2 approval is refused.
  • Every paid answer comes with a receipt: amount, transaction hash and session totals.

Install

The server runs with uv (uvx facts402-mcp).

Claude Desktop

Add this to claude_desktop_config.json (Settings > Developer > Edit Config):

json
{  "mcpServers": {    "facts402": {      "command": "uvx",      "args": ["facts402-mcp"],      "env": {        "X402_PRIVATE_KEY": "0xYOUR_HOT_WALLET_KEY",        "X402_MAX_PER_CALL_USD": "0.30",        "X402_SESSION_BUDGET_USD": "2.00"      }    }  }}

Claude Code

bash
claude mcp add facts402 --scope user -e X402_PRIVATE_KEY=0xYOUR_HOT_WALLET_KEY -- uvx facts402-mcp

Cursor

Use ~/.cursor/mcp.json (global) or .cursor/mcp.json (project; keep the key out of version control):

json
{  "mcpServers": {    "facts402": {      "command": "uvx",      "args": ["facts402-mcp"],      "env": { "X402_PRIVATE_KEY": "0xYOUR_HOT_WALLET_KEY" }    }  }}

Windsurf

Use ~/.codeium/windsurf/mcp_config.json:

json
{  "mcpServers": {    "facts402": {      "command": "uvx",      "args": ["facts402-mcp"],      "env": { "X402_PRIVATE_KEY": "0xYOUR_HOT_WALLET_KEY" }    }  }}

Example prompts

  • "Which paid API should I use for web search? Show me the cheapest live one with real buyers."
  • "Validate IBAN DE89 3704 0044 0532 0130 00 and tell me the bank."
  • "Is IE6388047V a valid VAT number? What company is it?"
  • "Screen 'Banco Nacional de Cuba' against OFAC sanctions."
  • "How many business days are there in Germany between 21 Dec 2026 and 8 Jan 2027?"

Development (both servers)

This folder also holds the shared core used by base-memecoin-guard-mcp: the HTTP caller, the x402 wallet, the budget and the server plumbing. From A2A_MICROPAYMENTS_TRACK/mcp:

bash
python -m venv .venv.venv/bin/pip install -e "./facts402-mcp[test]" -e "./base-memecoin-guard-mcp[test]".venv/bin/pytest facts402-mcp && .venv/bin/pytest base-memecoin-guard-mcp     # unit tests, mocked HTTP.venv/bin/pytest -m live facts402-mcp && .venv/bin/pytest -m live base-memecoin-guard-mcp   # live, never pays.venv/bin/python scripts/sync_schemas.py     # refresh input schemas and prices from the live /openapi.json.venv/bin/python scripts/write_manifest.py   # refresh each manifest.json (MCPB) from the code

Source: facts402-mcp/README.md at commit 6120ebc

Tools

14

x402_recommend

Find the right paid x402 API

Which paid API should I call for this task? Describe the need in plain words (e.g. 'web search', 'honeypot check base token', 'IBAN validation') and get the top-k x402 endpoints across the ecosystem: url, method, price, payment network, 30-day on-chain buyers, live 402 probe, risk flags and score, ranked by relevance, real buyers, recency and liveness (x402-list.com catalog, CC BY 4.0, plus sellers' own 402 quotes). Use it before paying an unknown API. No match = 404, not charged. Price: $0.005 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parameterskneedrequirednetworkmax_price

x402_recommend_preview

x402 API finder preview

Free teaser of x402_recommend: the single top pick (host, price, 30-day payers) for a need, without url, risk flags or ranking details. FREE: no wallet or payment needed.

Parametersneedrequired

iban_check

IBAN and BIC validation

Validate an IBAN (structure, mod-97 and national BBAN checksum) and return country, bank code, account code, bank name, BIC/SWIFT and SEPA membership. Use before a payout, invoice or SEPA transfer. Price: $0.01 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parametersibanrequired

eu_vat_check

EU VAT number check (VIES)

Validate an EU VAT number: offline format and check-digit test plus a live lookup in the European Commission VIES, returning registration status, company name and address. For B2B invoicing, reverse charge, KYB and onboarding. Price: $0.01 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parametersvat_numberrequired

sanctions_screen

OFAC sanctions screening

Fuzzy-screen a person, company, vessel or aircraft name against the US Treasury OFAC SDN sanctions list including aliases (refreshed every 6 h): matches with score, type, sanctions programs and remarks, plus the closest near-miss. AML / KYC / KYB compliance screening aid. Price: $0.01 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parametersnamerequiredmin_scoreentity_type

lei_lookup

LEI company lookup (GLEIF)

Look up a legal entity in the official GLEIF LEI index: by 20-character LEI get legal name, status, jurisdiction, addresses, registration dates and direct/ultimate parent; or search by company name for up to 5 candidates. For KYB, onboarding and finance agents. Price: $0.01 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parametersleiname

phone_check

Phone number validation

Validate and normalise any phone number worldwide: valid/possible, E.164 and national formats, country, line type (mobile, fixed line, toll-free, VoIP), original carrier, location and time zones. For CRM, outreach, KYC and calling agents. Price: $0.01 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parametersnumberrequireddefault_region

email_check

Email address check

Check an email address before sending: RFC syntax and normalisation, live DNS and MX records, null MX, disposable/throwaway domain and role-account (info@, support@) flags. No SMTP probing. For lead-gen, signup and outreach agents. Price: $0.01 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parametersemailrequired

fx_convert

ECB currency conversion

Convert an amount between ~30 currencies at official European Central Bank (ECB) reference exchange rates, latest or any day in the last 90 days, with the publication date used and exact decimal results. For pricing, invoicing, travel-budget and accounting agents. Price: $0.01 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parameterstorequireddatefromrequiredamountrequired

domain_check

Domain age and RDAP/WHOIS

Registration facts for any domain via RDAP (the WHOIS successor): registered or not, creation and expiry dates, domain age in days, registrar, EPP status, nameservers and DNSSEC. For fraud, phishing link-safety, lead-qualification and KYB agents. Price: $0.01 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parametersdomainrequired

business_days

Business days and public holidays

Count business days between two dates for a country (optionally a state/region) and list the public holidays and weekends in the range. For payment deadlines, SLAs, delivery dates and scheduling. Price: $0.01 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parametersendrequiredstartrequiredcountryrequiredsubdivision

weather_forecast

Weather forecast

Weather forecast for any latitude/longitude: current conditions plus up to 7 local-day summaries (min/max temperature, precipitation, wind, weather symbol) in the place's own time zone. Data from MET Norway. For travel, events and logistics agents. Price: $0.01 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parameterslatrequiredlonrequireddays

sun_times

Sunrise and sunset times

Sunrise, sunset, solar noon, civil dawn/dusk, golden hour and day length for any coordinates and date, in local time; polar day/night flagged. For travel, photography, events and outdoor planning. Price: $0.01 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parameterslatrequiredlonrequireddate

base_token_check

Base token contract facts

Raw on-chain facts for a Base mainnet ERC-20 token contract, read at one block: is it a contract, EIP-1967 proxy / implementation / admin, name, symbol, decimals, totalSupply, owner, and whether mint, pause or blacklist function selectors appear in the bytecode. Facts only, no rating. Price: $0.01 USDC per call via x402 on Base, paid from your own wallet (X402_PRIVATE_KEY) within your per-call cap and session budget; charged only for a successful answer.

Parameterstokenrequired

Version history

1
  1. v0.1.1LatestNov 1, 2026

Score

80% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts
  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listedRequired15 pts
  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts

    Declare a license in the repository or the registry entry.

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