aid: universal-hydrogen
name: Universal Hydrogen
description: >-
  Universal Hydrogen Co. was a Hawthorne, California hydrogen-aviation startup founded in 2020
  by former Airbus CTO Paul Eremenko to decarbonize regional air travel. Rather than building a
  hydrogen pipeline network, it proposed a modular capsule model: lightweight hydrogen capsules
  loaded into aircraft with existing cargo handling equipment, paired with fuel-cell powertrain
  conversion kits for regional turboprops such as the ATR 72 and De Havilland Dash 8. In March
  2023 it flew a converted Dash 8-300 testbed with one propeller driven by a hydrogen fuel cell.
  The company raised roughly $100 million from backers including GE Aviation, American Airlines,
  JetBlue Ventures, Airbus Ventures, Toyota Ventures and Mitsubishi. Unable to raise further
  equity or debt or to find a buyer, it ceased operations on 27 June 2024 and liquidated. It was
  a hardware and fuel-logistics business and never shipped a public API, SDK, developer portal
  or machine-readable specification; its domains no longer serve a site.
url: https://raw.githubusercontent.com/api-evangelist/universal-hydrogen/refs/heads/main/apis.yml
x-type: company
x-source: harvest:secondary-market
x-tier: stub
x-tier-reason: harvest
specificationVersion: '0.20'
x-status: defunct
x-status-detail: Ceased operations in 2024 after failing to raise further funding;
  hydrogen.aero no longer resolves. No Website registered on purpose.
created: '2026-09-02'
modified: '2026-09-02'
tags:
- Company
- Defunct
- Aviation
- Aerospace
- Hydrogen
- Clean Energy
- Fuel Cells
- Sustainability
- Decarbonization
- Hardware
- Logistics
tags_raw:
- Company
- Defunct
- Aviation
- Aerospace
- Hydrogen
- Clean Energy
- Fuel Cells
- Sustainability
- Decarbonization
- Hardware
- Logistics
apis: []
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: GitHubOrganization
  url: https://github.com/universal-hydrogen
  x-evidence: >-
    Verified 2026-09-02 via https://api.github.com/orgs/universal-hydrogen (HTTP 200) — org id
    71728862, display name "Universal Hydrogen Co.", blog https://www.hydrogen.aero, email
    hello@hydrogen.aero, created 2020-09-22. public_repos is 0, so it publishes no code,
    specifications or SDKs.
x-enrichment:
  date: '2026-09-02'
  status: minimal
  artifacts_added: 1
  pass: local-v1
x-coverage:
  state: none
  reason: defunct
  detail: >-
    Universal Hydrogen Co. ran out of cash and shut down on 27 June 2024, and both of its web
    hosts are gone: hydrogen.aero and www.hydrogen.aero answer a bare HTTP 404 "Unknown site"
    page on the root and on every /.well-known/ and specification path despite the A record
    still resolving, while universalhydrogen.com has been re-pointed to a Sedo parking lander
    whose wildcard catch-all returns the same parking HTML with a 200 on /llms.txt and
    /api-docs and CHEQ bot-filter 440/441 codes elsewhere. Its real GitHub organization is
    still live but holds zero public repositories, api./docs./developers.hydrogen.aero do not
    resolve, and the Wayback archive of the domain contains no developer or specification path
    — the company was a hydrogen fuel-capsule and powertrain hardware business that never
    published an API.
  evidence:
  - url: https://hydrogen.aero/
    status: 404
  - url: https://www.hydrogen.aero/
    status: 404
  - url: https://hydrogen.aero/openapi.json
    status: 404
  - url: https://hydrogen.aero/llms.txt
    status: 404
  - url: https://hydrogen.aero/.well-known/agent-card.json
    status: 404
  - url: https://hydrogen.aero/.well-known/agent.json
    status: 404
  - url: https://hydrogen.aero/.well-known/security.txt
    status: 404
  - url: https://universalhydrogen.com/
    status: 200
  - url: https://universalhydrogen.com/openapi.json
    status: 441
  - url: https://api.github.com/orgs/universal-hydrogen
    status: 200
  - url: https://registry.npmjs.org/universal-hydrogen
    status: 404
  checked: '2026-09-02'
x-notes:
  website_pointer_removed: >-
    The stub's only pointer was type Website -> https://forgeglobal.com/universal-hydrogen_stock/,
    a Forge Global secondary-market listing page. That is a trading-venue page, not Universal
    Hydrogen's web presence, and wiring it as Website credits the company with a live site it does
    not have (roadmap#56). Removed 2026-09-02. The company's own hydrogen.aero returns 404 and
    universalhydrogen.com is a Sedo parking lander, so no Website pointer is emitted at all. The
    Forge URL itself could not be re-verified: it answered HTTP 403 with a Cloudflare "Just a
    moment..." interstitial to both a browser User-Agent probe and WebFetch, which is a bot
    challenge rather than proof the page is dead.
  name_collision: >-
    Do not conflate with Hydrogen Platform (hydrogenplatform.com), an unrelated fintech that does
    publish a developer API. Searches for "Hydrogen API" surface that company, not this one.