# GreatHorn

**Canonical:** https://apis.io/providers/greathorn/  
**APIs profiled:** 0

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.

## Kin Score — 5.0 / 100 (minimal)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 5.0).

| Facet | Score |
|---|---|
| Discoverability | 50.0 |
| Contract Quality | 0.0 |
| Governance | 0.0 |
| Contract Governance | 0.0 |
| Operational Transparency | 0.0 |
| Developer Ergonomics | 0.0 |
| Commercial Clarity | 0.0 |
| Access Clarity | 0.0 |

## Agent readiness — 0.0 (human-only)

| Dimension | Value |
|---|---|
| Spec Presence | no |
| Agentic Access | no |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | no |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | no |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Unknown — onboarding: unknown, pricing: unknown, trial: no (confidence: low).

## Tags

Company, Email Security, Anti-Phishing, Cloud Email, Business Email Compromise, Microsoft-365, Google Workspace, Cybersecurity

---

Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/greathorn/). Scores are computed from the provider's own public artifacts under a published rubric.