2s Clinical API
The clinical API from 2s — 2 operation(s) for clinical.
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OpenAPI Specification
openapi: 3.2.0
info:
title: 2s — the (most) everything Clinical API
version: '1'
summary: The (most) everything API.
description: 'The (most) everything API for AI agents: 575+ pay-per-call endpoints on one origin.'
contact:
name: 2s
url: https://2s.io
email: alley@2s.io
x-logo:
url: https://2s.io/icon-512.png
altText: 2s
x-guidance: 'Pay-per-call REST API for AI agents — hundreds of endpoints returning ground-truth data (US public records, company & legal identifiers, finance/SEC, crypto/web3, security & CVEs, medical codes, weather & geocoding, agriculture, energy, maritime, music, and more). Every endpoint is paid per call in USDC via x402 (Base or Solana) — no API key, no signup. Call any endpoint with no auth to get a 402 PaymentRequirements envelope, sign it (EIP-3009 on Base, partial SPL transfer on Solana), and retry with the PAYMENT-SIGNATURE header. Add ?trial=1 for one free real call per endpoint per hour to test before paying. To discover the right endpoint: GET https://2s.io/api/directory for the full catalog, or GET https://2s.io/api/search/endpoints?q=<natural-language task> for a ranked match. Per-call price is on each operation as x-payment-info (from $0.001). Batch up to 50 calls behind one payment via POST https://2s.io/api/batch/run.'
servers:
- url: https://2s.io
tags:
- name: clinical
paths:
/api/clinical/study-detail:
get:
tags:
- clinical
summary: Full ClinicalTrials.gov study record by NCT id - the deep
description: Full ClinicalTrials.gov study record by NCT id — the deep detail beyond clinical.trial-search's summary. Returns the brief + detailed description, status, phases, conditions, study design (allocation, intervention model, primary purpose, masking), enrollment, interventions, primary and secondary outcome measures (with time frames), full eligibility criteria (inclusion/exclusion text, sex, age range, healthy-volunteers, standard age groups), lead sponsor and collaborators, all facility locations (name, city, state, country), whether results are posted, and key dates. Free, public-domain (NIH NLM). Use clinical.trial-search to find an NCT id, then this for the complete protocol.
operationId: clinical_study-detail
deprecated: false
security:
- x402Payment: []
responses:
'200':
description: 'Normalized envelope: items = [one full study record] (or [] if not found); total = 1 or 0.'
content:
application/json:
schema:
type: object
required:
- data
- meta
properties:
data:
type: object
properties:
ok:
type: boolean
enum:
- true
items:
type: array
items:
type: object
properties:
nctId:
type: string
nullable: true
briefTitle:
type: string
nullable: true
officialTitle:
type: string
nullable: true
status:
type: string
nullable: true
studyType:
type: string
nullable: true
phases:
type: array
items:
type: string
conditions:
type: array
items:
type: string
briefSummary:
type: string
nullable: true
detailedDescription:
type: string
nullable: true
eligibility:
type: object
properties:
criteria:
type: string
nullable: true
sex:
type: string
nullable: true
minimumAge:
type: string
nullable: true
maximumAge:
type: string
nullable: true
healthyVolunteers:
type: boolean
nullable: true
stdAges:
type: array
items:
type: string
required:
- criteria
- sex
- minimumAge
- maximumAge
- healthyVolunteers
- stdAges
additionalProperties: false
design:
type: object
properties:
allocation:
type: string
nullable: true
interventionModel:
type: string
nullable: true
primaryPurpose:
type: string
nullable: true
masking:
type: string
nullable: true
required:
- allocation
- interventionModel
- primaryPurpose
- masking
additionalProperties: false
enrollmentCount:
type: number
nullable: true
interventions:
type: array
items:
type: object
properties:
type:
type: string
nullable: true
name:
type: string
nullable: true
required:
- type
- name
additionalProperties: false
primaryOutcomes:
type: array
items:
type: object
properties:
measure:
type: string
nullable: true
timeFrame:
type: string
nullable: true
required:
- measure
- timeFrame
additionalProperties: false
secondaryOutcomes:
type: array
items:
type: object
properties:
measure:
type: string
nullable: true
timeFrame:
type: string
nullable: true
required:
- measure
- timeFrame
additionalProperties: false
leadSponsor:
type: string
nullable: true
collaborators:
type: array
items:
type: string
locations:
type: array
items:
type: object
properties:
facility:
type: string
nullable: true
city:
type: string
nullable: true
state:
type: string
nullable: true
country:
type: string
nullable: true
required:
- facility
- city
- state
- country
additionalProperties: false
hasResults:
type: boolean
startDate:
type: string
nullable: true
completionDate:
type: string
nullable: true
lastUpdatePostedDate:
type: string
nullable: true
url:
type: string
nullable: true
required:
- nctId
- briefTitle
- officialTitle
- status
- studyType
- phases
- conditions
- briefSummary
- detailedDescription
- eligibility
- design
- enrollmentCount
- interventions
- primaryOutcomes
- secondaryOutcomes
- leadSponsor
- collaborators
- locations
- hasResults
- startDate
- completionDate
- lastUpdatePostedDate
- url
additionalProperties: false
total:
type: integer
nullable: true
description: Total matching rows upstream; null when unknown.
source:
$ref: '#/components/schemas/Source'
required:
- ok
- items
- total
- source
additionalProperties: false
meta:
$ref: '#/components/schemas/CallMeta'
'400':
$ref: '#/components/responses/BadRequest'
'402':
$ref: '#/components/responses/PaymentRequired'
'405':
$ref: '#/components/responses/MethodNotAllowed'
'500':
$ref: '#/components/responses/ServerError'
'502':
$ref: '#/components/responses/UpstreamError'
x-2s-id: clinical.study-detail
x-2s-version: null
x-2s-price:
usd: 0.0036
x-2s-accepts:
- x402
x-2s-response-shape: normalized
x-payment-info:
price:
mode: fixed
currency: USD
amount: '0.003600'
protocols:
- x402: {}
parameters:
- name: nctId
in: query
required: true
description: Nct ID.
schema:
type: string
pattern: ^NCT\d{8}$
- $ref: '#/components/parameters/TrialMode'
/api/clinical/trial-search:
get:
tags:
- clinical
summary: Search ClinicalTrials.gov - every registered US (and many
description: '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.'
operationId: clinical_trial-search
deprecated: false
security:
- x402Payment: []
responses:
'200':
description: 'Normalized envelope: items = ClinicalTrials.gov studies; total = null (upstream paginates by opaque token, no true count); meta.nextPageToken for the next page; meta.query echoes the search.'
content:
application/json:
schema:
type: object
required:
- data
- meta
properties:
data:
type: object
properties:
ok:
type: boolean
enum:
- true
items:
type: array
items:
type: object
properties:
nctId:
type: string
briefTitle:
type: string
nullable: true
officialTitle:
type: string
nullable: true
status:
type: string
nullable: true
phases:
type: array
items:
type: string
studyType:
type: string
nullable: true
conditions:
type: array
items:
type: string
interventions:
type: array
items:
type: object
properties:
type:
type: string
nullable: true
name:
type: string
nullable: true
required:
- type
- name
additionalProperties: false
enrollmentCount:
type: integer
nullable: true
enrollmentType:
type: string
nullable: true
startDate:
type: string
nullable: true
primaryCompletionDate:
type: string
nullable: true
completionDate:
type: string
nullable: true
leadSponsor:
type: string
nullable: true
leadSponsorClass:
type: string
nullable: true
hasResults:
type: boolean
studyFirstPostedDate:
type: string
nullable: true
lastUpdatePostedDate:
type: string
nullable: true
briefSummary:
type: string
nullable: true
url:
type: string
format: uri
required:
- nctId
- briefTitle
- officialTitle
- status
- phases
- studyType
- conditions
- interventions
- enrollmentCount
- enrollmentType
- startDate
- primaryCompletionDate
- completionDate
- leadSponsor
- leadSponsorClass
- hasResults
- studyFirstPostedDate
- lastUpdatePostedDate
- briefSummary
- url
additionalProperties: false
total:
type: integer
nullable: true
description: Total matching rows upstream; null when unknown.
source:
$ref: '#/components/schemas/Source'
meta:
type: object
properties:
query:
type: object
properties:
query:
type: string
nullable: true
nctId:
type: string
nullable: true
status:
type: string
nullable: true
sponsor:
type: string
nullable: true
phase:
type: string
nullable: true
country:
type: string
nullable: true
pageSize:
type: integer
required:
- query
- nctId
- status
- sponsor
- phase
- country
- pageSize
additionalProperties: false
nextPageToken:
type: string
nullable: true
required:
- query
- nextPageToken
additionalProperties: false
required:
- ok
- items
- total
- source
additionalProperties: false
meta:
$ref: '#/components/schemas/CallMeta'
'400':
$ref: '#/components/responses/BadRequest'
'402':
$ref: '#/components/responses/PaymentRequired'
'405':
$ref: '#/components/responses/MethodNotAllowed'
'500':
$ref: '#/components/responses/ServerError'
'502':
$ref: '#/components/responses/UpstreamError'
x-2s-id: clinical.trial-search
x-2s-version: null
x-2s-price:
usd: 0.003
x-2s-accepts:
- x402
x-2s-response-shape: normalized
x-payment-info:
price:
mode: fixed
currency: USD
amount: '0.003000'
protocols:
- x402: {}
parameters:
- name: query
in: query
required: false
description: Free-text search query.
schema:
type: string
minLength: 2
maxLength: 300
- name: nctId
in: query
required: false
description: Nct ID.
schema:
type: string
pattern: ^NCT\d{8}$
- name: status
in: query
required: false
description: Filter results by status.
schema:
type: string
enum:
- RECRUITING
- ACTIVE_NOT_RECRUITING
- COMPLETED
- TERMINATED
- WITHDRAWN
- NOT_YET_RECRUITING
- SUSPENDED
- name: sponsor
in: query
required: false
description: Sponsor.
schema:
type: string
minLength: 2
maxLength: 200
- name: phase
in: query
required: false
description: Phase.
schema:
type: string
minLength: 2
maxLength: 40
- name: country
in: query
required: false
description: Country name or ISO country code.
schema:
type: string
minLength: 2
maxLength: 80
- name: pageSize
in: query
required: false
description: Number of results to return per page.
schema:
type: integer
minimum: 1
maximum: 100
default: 10
- name: pageToken
in: query
required: false
description: Page token.
schema:
type: string
minLength: 1
maxLength: 500
- $ref: '#/components/parameters/TrialMode'
components:
schemas:
Source:
type: object
description: 'Provenance of the data: upstream provider, source URL, and license.'
properties:
provider:
type: string
description: Upstream data provider.
url:
type: string
description: Source URL or documentation link.
license:
type: string
description: License / usage terms for the data.
CallMeta:
type: object
description: Per-call meta envelope — endpoint id, cost, caller kind, settlement details.
X402PaymentRequiredV2:
type: object
description: x402 v2 PaymentRequired envelope. Pick any entry from accepts[], sign for that rail, retry with the PAYMENT-SIGNATURE header.
required:
- x402Version
- accepts
properties:
x402Version:
type: integer
const: 2
error:
type: string
description: Human-readable reason payment is required.
resource:
type: string
description: The resource URL being purchased.
accepts:
type: array
description: Payment requirement options, one per supported network (Base USDC, Solana USDC).
items:
type: object
required:
- scheme
- network
- amount
- asset
- payTo
- maxTimeoutSeconds
properties:
scheme:
type: string
enum:
- exact
network:
type: string
description: CAIP-2 network id, e.g. "eip155:8453" (Base) or "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp".
amount:
type: string
description: Price in atomic asset units (USDC has 6 decimals).
asset:
type: string
description: Asset contract address / mint.
payTo:
type: string
description: Treasury address to pay.
maxTimeoutSeconds:
type: integer
extra:
type: object
description: 'Rail-specific extras (EVM: EIP-712 domain name/version; Solana: feePayer).'
additionalProperties: true
extensions:
type: object
description: Optional discovery metadata (e.g. bazaar input/output schemas).
additionalProperties: true
responses:
PaymentRequired:
description: Payment required. Body contains the x402 PaymentRequirements envelope with a multi-network accepts array; the per-call price is in accepts[].amount (and on the operation as x-2s-price). Sign for whichever rail you hold USDC on (EIP-3009 for Base, partial SPL transfer for Solana) and retry with the PAYMENT-SIGNATURE header (X-PAYMENT also accepted for v1 clients).
content:
application/json:
schema:
$ref: '#/components/schemas/X402PaymentRequiredV2'
UpstreamError:
description: Upstream provider error.
MethodNotAllowed:
description: Method not allowed — see `Allow` header for the supported method.
ServerError:
description: Internal server error.
BadRequest:
description: Bad request — invalid parameters.
parameters:
TrialMode:
name: trial
in: query
required: false
description: 'Try before you buy. Set to 1 for one free real call per endpoint per hour — no wallet or payment needed — to verify the endpoint before paying. Equivalent to sending the "X-2s-Trial: 1" request header. Works on every endpoint.'
schema:
type: integer
enum:
- 1
securitySchemes:
x402Payment:
type: apiKey
in: header
name: PAYMENT-SIGNATURE
description: 'x402 protocol v2: base64-encoded PaymentPayload. Call any paid endpoint without auth to receive a 402 with a multi-network PaymentRequirements envelope. Sign for either rail: EIP-3009 transferWithAuthorization (Base USDC) OR a partial SPL token transfer (Solana USDC). Retry with PAYMENT-SIGNATURE header. X-PAYMENT is also accepted for v1 buyer clients. See https://x402.org.'