clinical.trial-search

Search ClinicalTrials.gov — every registered US (and many international) clinical study (~500k trials). Free-text query matches title + condition + intervention; or direct lookup by NCT ID. Optional filters: recruitment status, lead sponsor, phase (PHASE1..PHASE4), country. Each record includes NCT ID, brief + official title, status, phases, study type, conditions list, interventions (with type + name), enrollment count + type, key dates (start / primary completion / completion / first posted / last update), lead sponsor + class (INDUSTRY/NIH/OTHER), hasResults flag, brief summary, and canonical clinicaltrials.gov URL. Public-domain NIH NLM data.

price

$0.0012 USDC per call

method

GET/api/clinical/trial-search

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
`query`	string	min 2 chars · max 300 chars
`nctId`	string	match ^NCT\d{8}$
`status`	string	one of: RECRUITING \| ACTIVE_NOT_RECRUITING \| COMPLETED \| TERMINATED \| WITHDRAWN \| NOT_YET_RECRUITING \| SUSPENDED
`sponsor`	string	min 2 chars · max 200 chars
`phase`	string	min 2 chars · max 40 chars
`country`	string	min 2 chars · max 80 chars
`pageSize`	integer	min 1 · max 100
`pageToken`	string	min 1 chars · max 500 chars

Code samples

cURLbash

# 1. Probe with no auth → 402 envelope with PaymentRequirements
curl -sS 'https://2s.io/api/clinical/trial-search?query=xx&nctId=example&status=RECRUITING&sponsor=xx&phase=xx&country=xx&pageSize=10&pageToken=example'

# 2. Sign + retry with PAYMENT-SIGNATURE:
curl -sS 'https://2s.io/api/clinical/trial-search?query=xx&nctId=example&status=RECRUITING&sponsor=xx&phase=xx&country=xx&pageSize=10&pageToken=example' \
  -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/clinical/trial-search?query=xx&nctId=example&status=RECRUITING&sponsor=xx&phase=xx&country=xx&pageSize=10&pageToken=example'

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.clinical.trialSearch({
  "query": "xx",
  "nctId": "example",
  "status": "RECRUITING",
  "sponsor": "xx",
  "phase": "xx",
  "country": "xx",
  "pageSize": 10,
  "pageToken": "example"
})

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.clinical.trial_search(query="xx", nctId="example", status="RECRUITING", sponsor="xx", phase="xx", country="xx", pageSize=10, pageToken="example")

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": "clinical.trial-search",
    "arguments": {
      "query": "xx",
      "nctId": "example",
      "status": "RECRUITING",
      "sponsor": "xx",
      "phase": "xx",
      "country": "xx",
      "pageSize": 10,
      "pageToken": "example"
    }
  }
}

Response

Field	Type	Description
`query`	object
`returned`	integer
`nextPageToken`	string
`studies`	array
`source`	object

Example response datajson

{
  "query": {
    "query": "example",
    "nctId": "example",
    "status": "example",
    "sponsor": "example",
    "phase": "example",
    "country": "example",
    "pageSize": 1
  },
  "returned": 1,
  "nextPageToken": "example",
  "studies": [
    {
      "nctId": "example",
      "briefTitle": "example",
      "officialTitle": "example",
      "status": "example",
      "phases": [
        "example"
      ],
      "studyType": "example",
      "conditions": [
        "example"
      ],
      "interventions": [
        {
          "type": "example",
          "name": "example"
        }
      ],
      "enrollmentCount": 1,
      "enrollmentType": "example",
      "startDate": "example",
      "primaryCompletionDate": "example",
      "completionDate": "example",
      "leadSponsor": "example",
      "leadSponsorClass": "example",
      "hasResults": false,
      "studyFirstPostedDate": "example",
      "lastUpdatePostedDate": "example",
      "briefSummary": "example",
      "url": "https://example.com"
    }
  ],
  "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.