A protocol for radically accessible structured knowledge.

Underlay is what institutions use to steward, curate, and publish their data. Universities, libraries, foundations, research labs, and publishers maintain open, versioned collections that anyone can cite, fork, and build on.

A project of Knowledge Futures, a 501(c)(3) public charity.

Collections

A collection is a dataset published as typed JSON records. Each update is validated against its schemas and stored as a new, immutable version.

Versioned

Versions are numbered (v1.2.0) and immutable. Earlier versions remain available, so any result can be traced to the data it used.

Self-describing

Every record type has a JSON Schema, and every collection has a README stating its source and license.

Citable

Collections and versions receive ARK identifiers for use in citations and data availability statements.

Open and portable

Public collections are readable without an account. Any version can be exported in full, and the published protocol allows other hosts to serve the same data.

nasa/exoplanets

NASA Exoplanet Archive

Version
v1.0.0latest · 11,098 records
Types
Planet6,298Star4,716DiscoveryFacility73DiscoveryMethod11
Record
{ "id": "11-com-b", "type": "Planet",
  "data": {
    "discoveryFacilityId": "xinglong-station",
    "discoveryMethodId": "radial-velocity",
    "discoveryYear": 2007,
    "eccentricity": 0.238
  } }
ARK
underlay.org/ark:12345/ulk2fdf75pwx6dp.v1.0.0
Imported from the NASA Exoplanet Archive by Knowledge Futures.

Using the data

Public collections require no account or API key. Examples use nasa/exoplanets.

Web interface

Each collection page shows its README, record types, schemas, and version history. Records can be filtered by type, and any two versions can be compared.

Open nasa/exoplanets →
underlay.org/nasa/exoplanets/records?type=Planet
OverviewRecordsSchemasVersionsFiles
TypeRecords
Planet6,298
Star4,716
DiscoveryFacility73
DiscoveryMethod11

In the registry

wikidata/us-public-librariesUS Public LibrariesPublic libraries across the United States, sourced from Wikidata.9,639 recordsv1.0.0Geographynasa/exoplanetsNASA Exoplanet ArchiveConfirmed exoplanets and their host stars from NASA's Exoplanet Archive, with discovery methods, facilities, and orbital parameters.11.1K recordsv1.0.0Sciencegbif/north-american-birdsNorth American Bird SpeciesBird species observed in North America from the Global Biodiversity Information Facility (GBIF) — species profiles, taxonomic classification, occurrence records, and contributing datasets.10.5K recordsv1.0.0Natureopenfood/us-productsOpen Food Facts — US ProductsFood products sold in the United States from Open Food Facts — nutrition data, ingredients, brands, categories, and eco-scores.904 recordsv1.0.0Food & Drinkreference/world-universitiesWorld UniversitiesUniversities and higher education institutions from 201 countries worldwide.10.4K recordsv1.0.0Geography, Academicnih/clinical-trialsNIH Clinical Trials — Alzheimer'sClinical trials for Alzheimer's disease from ClinicalTrials.gov — studies, conditions, interventions, sponsors, and outcomes.29.1K recordsv1.0.0Science, Health
Includes reference datasets imported from public sources by Knowledge Futures. Sources and licenses are listed in each README.Search all collections →

For institutions that steward data

Researchers and labs

Publish the data behind published results, with a version and identifier that match each paper.

Journals and publishers

Publish article metadata, reviews, and claims as typed records that indexers can query. Updates never break existing links.

Archives and libraries

Maintain catalogs with their full history, readable by people and machines and exportable in full.

Developers and data teams

Integrate a pinned version into an app or pipeline, and review the changes in each new version before adopting it.

Publishing

Data is published in its existing structure. Schemas describe it once, and each subsequent push creates a new version.

  1. 1

    Create a collection

    Sign in with a Knowledge Futures account and create a public or private collection under a personal or organization account.

  2. 2

    Define schemas

    Each record type is described by a JSON Schema. Records that fail validation are rejected.

  3. 3

    Push a version

    Records are pushed through the API and committed as a numbered, immutable version.

Read the quickstartSign inInstitutional publishing: help@underlay.org

Nonprofit, open, and portable.

Underlay is built by Knowledge Futures, a 501(c)(3) public charity building the tools communities need to share, curate, and steward knowledge openly and sustainably. Its protocol, code, and export format are open, so collections never depend on a single host.

Run by a nonprofit

Each Knowledge Futures project adds to an open-source, privacy-respecting foundation for public knowledge.

About Knowledge Futures

Open protocol

Records, versions, and hashing are defined in a public specification.

Read the protocol

Open source

The registry’s source code is public on GitHub.

View on GitHub

Portable

Every version exports in full, with schemas and hashes, for independent verification or hosting elsewhere.

How export works