GreatHorn
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.
Index entry only — little beyond a description and a link, and nothing machine-readable enough for an agent to act on without a human reading the site first.
GreatHorn is tracked in the API Evangelist network. This page is the human-readable profile that sits on top of the machine-readable index we maintain at apis.io.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — GreatHorn scores 6.8/100 (minimal), with a separate agent-readiness read of 0/100 (human only). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
GreatHorn is in the network as a tracked entity. We haven't yet indexed a public API surface for it — when one is published, the artifacts, score, and agent-readiness read will appear here automatically. The source repository is where that profile is built.
← All providers · Data indexed from github.com/api-evangelist/greathorn · machine-readable index on apis.io