US 501(c) nonprofit organization search. Lookup by 9-digit EIN (with or without hyphen), free-text name, 2-letter state, NTEE category code (e.g. 'B99' for education), or IRS subsection code (3 = 501(c)(3), 4 = 501(c)(4), etc.). Each record includes EIN, name, city/state, NTEE code, subsection code + human-readable subsection description (e.g. '501(c)(3) Charitable / Religious / Educational'), and relevance score. Sourced from ProPublica Nonprofit Explorer, which aggregates IRS Form 990 + BMF data; underlying IRS data is public domain.
/api/nonprofit/searchPAYMENT-SIGNATURE.The search API is a pay-per-call nonprofit endpoint built for AI agents and autonomous software. US 501(c) nonprofit organization search.
There is no signup and no API key. An agent (or any HTTP client) hits the endpoint, receives an x402 "402 Payment Required" challenge, signs a sub-cent USDC payment on Base or Solana, and retries — the data comes back on the paid request. That makes it a drop-in search data source for an agent tool-use loop, an MCP host, or a backend that needs nonprofit data on demand without onboarding to yet another vendor portal.
| Name | Type | Description |
|---|---|---|
q | string | min 2 chars · max 200 chars |
ein | string | min 9 chars · max 11 chars · match ^\d{2}-?\d{7}$ |
state | string | min 2 chars · max 2 chars · match ^[A-Za-z]{2}$ |
nteeCode | string | match ^[A-Za-z][0-9]{1,3}$ |
subsectionCode | integer | min 2 · max 92 |
page | integer | min 0 · max 99 |
# 1. Probe with no auth → 402 envelope with PaymentRequirements curl -sS 'https://2s.io/api/nonprofit/search?q=xx&ein=12345&state=xx&nteeCode=example&subsectionCode=2&page=0' # 2. Sign + retry with PAYMENT-SIGNATURE: curl -sS 'https://2s.io/api/nonprofit/search?q=xx&ein=12345&state=xx&nteeCode=example&subsectionCode=2&page=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/nonprofit/search?q=xx&ein=12345&state=xx&nteeCode=example&subsectionCode=2&page=0'
import { TwoS } from '@2sio/sdk'
const client = new TwoS({
privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})
const result = await client.nonprofit.search({
"q": "xx",
"ein": "12345",
"state": "xx",
"nteeCode": "example",
"subsectionCode": 2,
"page": 0
})
console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)import os
from twosio import TwoS
client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])
result = client.nonprofit.search(q="xx", ein="12345", state="xx", nteeCode="example", subsectionCode=2, page=0)
print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)// 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": "nonprofit.search",
"arguments": {
"q": "xx",
"ein": "12345",
"state": "xx",
"nteeCode": "example",
"subsectionCode": 2,
"page": 0
}
}
}| Field | Type | Description |
|---|---|---|
ok | boolean | one of: true |
items | array | |
total | integer | Total matching rows upstream; null when unknown. |
source | object | |
page | object | |
meta | object |
{
"ok": true,
"items": [
{
"ein": "example",
"einFormatted": "example",
"name": "example",
"subName": "example",
"city": "example",
"state": "example",
"nteeCode": "example",
"subsectionCode": 1,
"subsectionDesc": "example",
"score": 1
}
],
"total": 1,
"source": {
"provider": "example",
"url": "example",
"license": "example"
},
"page": {
"number": 1,
"size": 1,
"pages": 1
},
"meta": {
"query": {
"q": "example",
"ein": "example",
"state": "example",
"nteeCode": "example",
"subsectionCode": 1,
"page": 1
},
"returned": 1
}
}