How AI is applied across API Evangelist and APIs.io. Read my AI disclosure →
API Evangelist API Evangelist
Discovery
Learnings
Guidance
Toolbox
Alignment
API Evangelist LLC
Discovery
Learnings
Guidance
Toolbox
Alignment
API Evangelist LLC

Need help?

Contact us
National Institutes of Health (NIH)

National Institutes of Health (NIH) Stats API

Data statistics

Documentation Provider Profile APIs.io OpenAPI GitHub

National Institutes of Health (NIH) Stats API is one of 15 APIs that National Institutes of Health (NIH) publishes on the APIs.io network, described by a machine-readable OpenAPI specification.

Tagged areas include Stats. The published artifact set on APIs.io includes an OpenAPI specification and API documentation.

This API exposes 3 operations across 3 paths, and defines 18 schemas. It is described by OpenAPI 3.2.0, at version 2.0.5.

Requests are made against a single base URL, https://clinicaltrials.gov/api/v2.

3 operations 3 paths 18 schemas 3 GET

Metadata

The identity and technical contract details declared by the specification.

Specification
OpenAPI 3.2.0
API Version
2.0.5
Base URL
https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
Resource Areas
1

Paths & Operations 3

Across 3 paths, the API surfaces 3 operations — 3 GET. Each is listed below with its method, path, parameters, and response codes.

Stats 3

Data statistics

GET
/stats/size
Study Sizes
sizeStats → 200400
GET
/stats/field/values
Field Values
fieldValuesStats 2 params → 200400404
GET
/stats/field/sizes
List Field Sizes
listFieldSizesStats 1 param → 200400404

Schemas 18

The contract defines 18 schemas that model the data the API accepts and returns. The most detailed are IntegerStats (7 properties), NumberStats (7 properties), StringStats (7 properties), DateStats (7 properties). Each schema is shown below with its type and property counts.

ListSizesList
array
GzipStats
object
5 properties 5 required
FieldStatsType
string
EnumStats
object
6 properties 5 required
errorMessage
string
A text message describing an error
StudySize
object
2 properties 2 required
ValueCount
object
2 properties 2 required
FieldValuesStatsList
array
LongestString
object
3 properties 3 required
BooleanStats
object
6 properties 6 required
StringStats
object
7 properties 5 required
ListSizes
object
6 properties 3 required
DateStats
object
7 properties 5 required
ListSize
object
2 properties 2 required
FieldValuesStats
DistItem
object
2 properties 2 required
NumberStats
object
7 properties 4 required
IntegerStats
object
7 properties 4 required

Specification

The full machine-readable OpenAPI contract behind this narrative.

Source

nih-stats-api-openapi.yml Raw ↑

Other APIs National Institutes of Health (NIH) publishes across the network.

NCBI E-utilities (Entrez Programming Utilities)
AE Profile APIs.io
PubChem Power User Gateway (PUG REST)
AE Profile APIs.io
NIH RePORTER API
AE Profile APIs.io
NCBI BLAST URL API
AE Profile APIs.io
PubMed Central (PMC) OA API
AE Profile APIs.io
National Institutes of Health (NIH) BioSample API
AE Profile APIs.io
National Institutes of Health (NIH) Gene API
AE Profile APIs.io
National Institutes of Health (NIH) Genome API
AE Profile APIs.io
National Institutes of Health (NIH) Organelle API
AE Profile APIs.io
National Institutes of Health (NIH) Prokaryote API
AE Profile APIs.io
National Institutes of Health (NIH) Studies API
AE Profile APIs.io
National Institutes of Health (NIH) Taxonomy API
AE Profile APIs.io
#Stats
← Back to N APIs
API Details
ID
nih:nih-stats-api
Base URL
https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
Docs
https://www.ncbi.nlm.nih.gov/home/develop/api/
Provider
National Institutes of Health (NIH)
APIs.io →  GitHub →
Explore more
All APIs Providers APIs.io Network
Work with this as data

Every API here is available over the API and to AI agents over MCP. APIs is not yet its own endpoint on the v1 API. Reach this content through network search and the tag graph, or the MCP server below.

Installs https://mcp.apievangelist.com/mcp in Claude, Cursor, VS Code and the rest — one button, every client.

MCP tools for apis
4 tools reach this content
  • search_api_evangelistSearch every content type across the network at once.
  • find_relatedThe shared-tag relevance graph — what else covers this.
  • get_tagEverything one tag labels, across all content types.
  • guide_topicPRO — a curated bundle for a topic: area, guidance, rules, papers, stories, services.
All tools & prompts
Call it yourself
curl for this page
Search the network for this 
curl "https://api.apievangelist.com/v1/search?q=nih-stats-api&limit=10"
Everything under a tag 
curl "https://api.apievangelist.com/v1/tags/nih-stats-api"

Discovery needs no key. Full bodies and the synthesis endpoints are Pro.

Get an API key

Free tier, no email required. Sign in with whichever identity you already have.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have. Your account

Where this information came from

This is an independent, third-party profile of National Institutes of Health (NIH) Stats API, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.

The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.

Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.

info@apievangelist.com · Read the full data-sourcing policy →
On a security or compliance team? Put security in the subject line and you will get a person, not a form — we will tell you exactly which public URLs this profile was built from.