bank.lookup

FDIC-insured US bank directory lookup. Lookup by name (fuzzy match), FDIC certificate number, RSSD ID, or state. Each record includes name + short name, web address, active flag, city/state/county/zip, established + insured dates, charter class, bank class, primary federal regulator, number of branches, assets and deposits ($1000s), and closed-date + reason for inactive institutions. Public-domain FDIC data, free.

price

$0.0012 USDC per call

method

GET/api/bank/lookup

payment

x402 v2 · USDC on Base (EIP-3009) or Solana (SPL transfer)

auth

None. Sign the payment, retry with PAYMENT-SIGNATURE.

tier

Tier 0 — no paid upstream

Parameters

Name	Type	Description
`name`	string	min 2 chars · max 200 chars
`cert`	string	match ^\d{1,7}$
`rssdId`	string	match ^\d{1,10}$
`state`	string	min 2 chars · max 2 chars · match ^[A-Za-z]{2}$
`status`	string	one of: active \| inactive \| any
`limit`	integer	min 1 · max 50
`offset`	integer	min 0 · max 10000

Code samples

cURLbash

# 1. Probe with no auth → 402 envelope with PaymentRequirements
curl -sS 'https://2s.io/api/bank/lookup?name=xx&cert=12345&rssdId=12345&state=xx&status=active&limit=10&offset=0'

# 2. Sign + retry with PAYMENT-SIGNATURE:
curl -sS 'https://2s.io/api/bank/lookup?name=xx&cert=12345&rssdId=12345&state=xx&status=active&limit=10&offset=0' \
  -H 'PAYMENT-SIGNATURE: <base64-json-payload>'

# Or use the canonical runner (handles probe → sign → retry):
#   EVM_PRIVATE_KEY=0x... node --env-file=.env.local \
#     --experimental-strip-types scripts/x402-pay.ts \
#     'https://2s.io/api/bank/lookup?name=xx&cert=12345&rssdId=12345&state=xx&status=active&limit=10&offset=0'

TypeScript / Node — @2sio/sdktypescript

import { TwoS } from '@2sio/sdk'

const client = new TwoS({
  privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})

const result = await client.bank.lookup({
  "name": "xx",
  "cert": "12345",
  "rssdId": "12345",
  "state": "xx",
  "status": "active",
  "limit": 10,
  "offset": 0
})

console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)

Python — 2siopython

import os
from twosio import TwoS

client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])

result = client.bank.lookup(name="xx", cert="12345", rssdId="12345", state="xx", status="active", limit=10, offset=0)

print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)

MCP — Claude Desktop / AgentKit / any MCP hostjson

// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
//    EVM_PRIVATE_KEY funds x402 payments per call.

// claude_desktop_config.json
{
  "mcpServers": {
    "2sio": {
      "command": "npx",
      "args": ["-y", "@2sio/mcp"],
      "env": { "EVM_PRIVATE_KEY": "0x..." }
    }
  }
}

// 2. Once the server is running, agents call this tool via standard MCP:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "bank.lookup",
    "arguments": {
      "name": "xx",
      "cert": "12345",
      "rssdId": "12345",
      "state": "xx",
      "status": "active",
      "limit": 10,
      "offset": 0
    }
  }
}

Response

Field	Type	Description
`query`	object
`totalCount`	integer
`returned`	integer
`banks`	array
`source`	object

Example response datajson

{
  "query": {
    "name": "example",
    "cert": "example",
    "rssdId": "example",
    "state": "example",
    "status": "example",
    "limit": 1,
    "offset": 1
  },
  "totalCount": 1,
  "returned": 1,
  "banks": [
    {
      "cert": "example",
      "rssdId": "example",
      "name": "example",
      "shortName": "example",
      "webAddress": "example",
      "active": false,
      "city": "example",
      "state": "example",
      "zipcode": "example",
      "county": "example",
      "establishedDate": "example",
      "insuredDate": "example",
      "charterClass": "example",
      "bankClass": "example",
      "primaryRegulator": "example",
      "numberOfBranches": 1,
      "assets": 1,
      "deposits": 1,
      "closedDate": "example",
      "reasonClosed": "example"
    }
  ],
  "source": {
    "provider": "example",
    "url": "https://example.com",
    "license": "example"
  }
}

Discovery

/api/directory — full catalog of every endpoint
/openapi.json — OpenAPI 3.1 spec (per-op x-payment-info, x402Payment security)
/.well-known/x402 — machine-readable service descriptor for x402-aware crawlers
/.well-known/mcp/server-card.json — MCP SEP-1649 server card
/llms.txt — plain-text manifest for LLM ingestion

2s.io is x402-native. Every call is paid per-request from a USDC-funded EVM wallet on Base — no signup, no API keys, no monthly fees. Source code: github.com/2s-io/sdk.