Verification APIs for AI agents, paid per call

Romanian company records and public tenders, US court dockets, OFAC sanctions and trademarks, and timestamped captures of web pages. Each tool is one HTTP route and one MCP tool. Agents pay per request with x402 or a prepaid key, without an account.

Try the playground Read the docs

The first 10 calls a day are free on every tool except proof_create
Failed calls are never charged
No account and no subscription

402checkNo. 000402

Pay to the order ofGET /v1/ro/company/14399840

402Payment Required

Amount$0.01

MemoUSDC on Base, network eip155:8453

SignedPAYMENT-SIGNATURE: eyJ4NDAyVmVyc2lvbiI6Mi…

200OK

{"cui":"14399840","name":…,"vatPayer":true,…}

One x402 call: the first request gets 402 with the price, the client signs a USDC payment and retries, the retry gets 200. With a credits key or within the free tier, the first request already returns 200.

Seven tools, priced per call

Every tool returns JSON. The price is charged only when the call succeeds; parameters and responses are in each tool's docs and in openapi.json.

Romania

Trade registry, VAT and financials by CUI; SICAP procurement notices.

`ro_company`

$0.01

Romanian company file by CUI: registry, VAT, address, financials.

GET /v1/ro/company/{cui}Docs Try

`ro_tenders`

$0.02

Search Romanian public tenders (SEAP/SICAP) by keyword or CPV code.

GET /v1/ro/tendersDocs Try

United States

Federal court records, OFAC sanctions screening and USPTO trademarks.

`us_court`

$0.02

Search US court dockets and opinions on CourtListener by party.

GET /v1/us/courtDocs Try

`us_sanctions`

$0.01

Screen a person or entity against OFAC sanctions lists, fuzzy matched.

GET /v1/us/sanctionsComing soonDocs Try

`us_trademark`

$0.02

Search US trademark applications and registrations (USPTO) by wordmark.

GET /v1/us/trademarkDocs Try

Web evidence

Hashed, timestamped captures of any public page, and their lookup.

`proof_create`

$0.25

Paid only: capture a web page as hashed, timestamped HTML and screenshot.

POST /v1/proofDocs Try

`proof_get`

free

Fetch an earlier proof: hashes, artifact links, anchor status.

GET /v1/proof/{id}Docs Try

Run a call now

This form calls ro_tenders on your free tier, with no key. Change the values and the curl command follows.

All seven tools in the playground

qoptional

Keyword in the contract title. q or cpv is required. 2–200 characters.

cpvoptional

8-digit CPV code. q or cpv is required.

countyoptional

Romanian county (place of performance), e.g. Cluj. Up to 40 characters.

fromoptional

Earliest publication date, inclusive.

tooptional

Latest publication date, inclusive; not before from.

limitoptional

Maximum number of notices. 1 to 50, default 20.

Without a key it runs on your free tier (10 calls a day per IP). An agent pays $0.02 per successful call.

Equivalent curl

curl "https://402check.com/v1/ro/tenders?q=software"

Three ways to pay, none needs an account

Order of evaluation on every call: a credits key, then the free tier, then x402.

Free tier

10 calls a day per IP address, no key, on every tool except proof_create (always paid). proof_get is always free.

Try the playground

Credits by card

Buy $5 or $20 and get an rk_ key, no registration. Send Authorization: Bearer rk_YOUR_KEY over HTTP or MCP.

Paid access: coming soon

x402

USDC on Base. Without a key, the HTTP API answers 402 with payment requirements; @x402/fetch pays and retries. HTTP only.

How to connect

Add it to your agent over MCP

Streamable HTTP at https://402check.com/mcp. Without a key, tool calls use the free tier.

Pick your client; the URL is the same everywhere.

Claude Code

claude mcp add --transport http 402check https://402check.com/mcp
# with a credits key:
claude mcp add --transport http 402check https://402check.com/mcp --header "Authorization: Bearer rk_YOUR_KEY"

Claude Desktop / claude.ai

Settings -> Connectors -> Add custom connector
Name: 402check
URL:  https://402check.com/mcp
# free tier; for a credits key use an mcp-remote bridge (verify with your client)

Codex (OpenAI) ~/.codex/config.toml

[mcp_servers.402check]
url = "https://402check.com/mcp"
# with a credits key:
# http_headers = { Authorization = "Bearer rk_YOUR_KEY" }

Cursor .cursor/mcp.json

{
  "mcpServers": {
    "402check": {
      "url": "https://402check.com/mcp"
    }
  }
}

Any MCP client (Streamable HTTP)

{
  "mcpServers": {
    "402check": {
      "url": "https://402check.com/mcp"
    }
  }
}

Generic JSON with a credits key

{
  "mcpServers": {
    "402check": {
      "url": "https://402check.com/mcp",
      "headers": {
        "Authorization": "Bearer rk_YOUR_KEY"
      }
    }
  }
}

Replace rk_YOUR_KEY with your key from /buy.