Heirloom

Heirloom Carbon Technologies, Inc. is a San Francisco Bay Area direct air capture (DAC) company that removes carbon dioxide from the atmosphere by accelerating the natural mineralization of limestone. Heirloom spreads calcium oxide on vertical trays where it re-absorbs atmospheric CO2 in days rather than years, then uses electric kilns to release the captured CO2 for permanent geologic or in-concrete storage. The company opened the first commercial DAC facility in the United States, sells permanent carbon removal credits to individuals, businesses and enterprises, and has signed offtake agreements with Microsoft, Frontier, United's Sustainable Flight Fund and CarbonCure. It is an industrial climate-technology company; it does not operate a public developer program or API.

Heirloom is profiled on the APIs.io network. Tagged areas include Company, Carbon Removal, Direct Air Capture, Climate Technology, and Carbon Credits.

Heirloom’s developer surface includes engineering blog, support, pricing, and 5 more developer resources.

🌐 Visit website 📡 Source on GitHub

12.7/100 emerging ▬ flat Agent 0/100 human only saas Full breakdown ↓
scored 2026-09-14 · rubric v0.22.0

0 APIs

Company Carbon Removal Direct Air Capture Climate Technology Carbon Credits Sustainability Energy Climate

Kin Score

Kin Score How this is scored →
scored 2026-09-14 · rubric v0.22.0

Composite quality — 12.7/100 · emerging

Contract Quality 0.0 / 21

Developer Ergonomics 1.2 / 17

Access Clarity 5.4 / 17

Operational Transparency 0.0 / 11

Contract Governance 0.0 / 10

Discoverability 4.3 / 9

Regulatory Posture 2.8 / 15

Agent readiness — 0/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Regulatory Posture applies to this provider. Its tags matched the Energy & Utilities regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/heirloom: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Security Posture 1

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Heirloom Domain Security

TLSv1.3 · HSTS

SECURITY

Resources

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 3

Pricing, plans, and the legal terms of use

Pricing

Pricing

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

SecondaryMarket

SecondaryMarket

Source (apis.yml)

aid: heirloom
name: Heirloom
description: Heirloom Carbon Technologies, Inc. is a San Francisco Bay Area direct air capture (DAC) company that removes
  carbon dioxide from the atmosphere by accelerating the natural mineralization of limestone. Heirloom spreads calcium oxide
  on vertical trays where it re-absorbs atmospheric CO2 in days rather than years, then uses electric kilns to release the
  captured CO2 for permanent geologic or in-concrete storage. The company opened the first commercial DAC facility in the
  United States, sells permanent carbon removal credits to individuals, businesses and enterprises, and has signed offtake
  agreements with Microsoft, Frontier, United's Sustainable Flight Fund and CarbonCure. It is an industrial climate-technology
  company; it does not operate a public developer program or API.
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: false
  label: Hosted service · you call their endpoint
  confidence: medium
  source:
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - security
  generated: '2026-09-02'
  method: derived
image: https://cdn.prod.website-files.com/639c8f646dc35afd81aeebc2/651aee726de0080273ee5ad9_Heirloom_SocialShare.jpg
url: https://raw.githubusercontent.com/api-evangelist/heirloom/refs/heads/main/apis.yml
x-type: company
x-source: harvest:secondary-market
x-tier: stub
x-tier-reason: harvest
specificationVersion: '0.20'
created: '2026-08-22'
modified: '2026-08-22'
tags:
- Company
- Carbon Removal
- Direct Air Capture
- Climate Technology
- Carbon Credits
- Sustainability
- Energy
- Climate
apis: []
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: DomainSecurity
  url: security/heirloom-domain-security.yml
- type: Website
  url: https://www.heirloomcarbon.com/
- type: Blog
  url: https://www.heirloomcarbon.com/news
- type: Support
  url: https://www.heirloomcarbon.com/contact-us
- type: Pricing
  url: https://www.heirloomcarbon.com/remove-co2
- type: TermsOfService
  url: https://www.heirloomcarbon.com/terms
- type: PrivacyPolicy
  url: https://www.heirloomcarbon.com/privacy
- type: SecondaryMarket
  url: https://www.hiive.com/securities/heirloom-stock
x-enrichment:
  date: '2026-08-22'
  status: minimal
  artifacts_added: 3
  pass: local-v1
x-coverage:
  state: none
  reason: not-a-software-company
  detail: Heirloom Carbon Technologies is an industrial direct air capture company that sells permanent CO2 removal credits
    through a Webflow storefront; its 46-URL sitemap contains no developer, docs or API page, no api./docs./developer./app./portal.
    subdomain resolves in DNS, and every /openapi.json, /llms.txt, /graphql and /.well-known/* path 404s on both www and apex.
  evidence:
  - url: https://www.heirloomcarbon.com/sitemap.xml
    status: 200
  - url: https://www.heirloomcarbon.com/openapi.json
    status: 404
  - url: https://www.heirloomcarbon.com/llms.txt
    status: 404
  - url: https://www.heirloomcarbon.com/.well-known/agent-card.json
    status: 404
  - url: https://heirloomcarbon.com/.well-known/security.txt
    status: 404
  checked: '2026-08-22'

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