aid: greathorn
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source: []
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/greathorn.png
name: GreatHorn
description: 'GreatHorn was a cloud-native email security company founded in 2015 in Waltham,
  Massachusetts, providing anti-phishing, spear-phishing, business email compromise (BEC), and
  account-takeover protection for Microsoft 365 and Google Workspace. Backed by Uncork Capital,
  it was acquired by Hornetsecurity in 2021. As of enrichment (July 2026) the greathorn.com
  domain returns HTTP 404 (Cloudflare, acquired/retired) and the company publishes no live
  developer portal, API documentation, or OpenAPI surface. No public API artifacts were found
  to enrich; this profile is retained as a historical/portfolio record.'
url: https://raw.githubusercontent.com/api-evangelist/greathorn/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- uncork-capital
x-tier: stub
x-tier-reason: portfolio-lead
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-07-19'
x-status: acquired
x-acquired-by: hornetsecurity
x-acquired-year: 2021
x-domain-status: '404'
tags:
- Company
- Email Security
- Anti-Phishing
- Cloud Email
- Business Email Compromise
- Microsoft 365
- Google Workspace
- Cybersecurity
apis: []
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence