# GreatHorn Mailbox Intelligence vs NotifySecurity: side-by-side comparison (2026)

[GreatHorn Mailbox Intelligence](https://cybersectools.com/tools/greathorn-mailbox-intelligence) is a commercial [Anti-Phishing](https://cybersectools.com/categories/anti-phishing) solution by [GreatHorn](https://cybersectools.com/companies/greathorn). [NotifySecurity](https://cybersectools.com/tools/notifysecurity) is a free [Anti-Phishing](https://cybersectools.com/categories/anti-phishing) solution. Features, integrations, deployment and the company behind each one, side by side.

## Side-by-side comparison

| | GreatHorn Mailbox Intelligence | NotifySecurity |
|---|---|---|
| Pricing model | Commercial | Free |
| Category | Anti-Phishing | Anti-Phishing |
| Verified | No | No |
| Deployment type | Cloud | Cloud |
| Company size fit | Startup, SMB, Mid-Market, Enterprise | SMB, Mid-Market, Enterprise |
| GitHub stars | – | 133 |
| Last commit | – | Nov 2018 |
| Company | GreatHorn | – |
| Headquarters | – | – |

### Use cases and capabilities

| | GreatHorn Mailbox Intelligence | NotifySecurity |
|---|---|---|
| Microsoft 365 | Yes | – |
| Outlook | – | Yes |
| SMTP | – | Yes |

### Core features

**GreatHorn Mailbox Intelligence**

10 features listed. Sign in on the page to see them.

**NotifySecurity**

No features listed.

### Integrations

**GreatHorn Mailbox Intelligence**

2 integrations listed. Sign in on the page to see them.

**NotifySecurity**

No integrations listed.

## Which one fits you

Based on what each listing shows: deployment, company size, price and open source.

- [GreatHorn Mailbox Intelligence](https://cybersectools.com/tools/greathorn-mailbox-intelligence) fits if you are a startup.
- [NotifySecurity](https://cybersectools.com/tools/notifysecurity) fits if you need a free product and you want an open-source product.

## GreatHorn Mailbox Intelligence vs NotifySecurity FAQ

Common questions when comparing GreatHorn Mailbox Intelligence vs NotifySecurity for Anti-Phishing.

### What is the difference between GreatHorn Mailbox Intelligence and NotifySecurity?

**GreatHorn Mailbox Intelligence**: Email security tool empowering users to identify & report phishing threats, built by GreatHorn.

**NotifySecurity**: An Outlook add-in that enables one-click reporting of suspicious emails to security teams with integrated statistics tracking and SMTP header collection.

The table above shows where their features, integrations, deployment and company size fit differ.

### Who makes GreatHorn Mailbox Intelligence and NotifySecurity?

**GreatHorn Mailbox Intelligence** is made by GreatHorn. **NotifySecurity** is open-source with 133 GitHub stars. The vendor behind a product decides its roadmap, support, and longevity, so check each company's profile before you commit.

### Is GreatHorn Mailbox Intelligence a good alternative to NotifySecurity?

Often, yes. GreatHorn Mailbox Intelligence and NotifySecurity are both Anti-Phishing products. Key differences: GreatHorn Mailbox Intelligence is Commercial while NotifySecurity is Free, NotifySecurity is open-source. Use the table above to see where features, deployment and company size fit differ.

## Related comparisons

- [GreatHorn Mailbox Intelligence vs Vade for M365](https://cybersectools.com/compare/greathorn-mailbox-intelligence-vs-vade-for-m365)
- [GreatHorn Mailbox Intelligence vs Egress Defend](https://cybersectools.com/compare/egress-defend-vs-greathorn-mailbox-intelligence)
- [GreatHorn Mailbox Intelligence vs PhishingBox KillPhish](https://cybersectools.com/compare/greathorn-mailbox-intelligence-vs-phishingbox-killphish)
- [NotifySecurity vs Vade for M365](https://cybersectools.com/compare/notifysecurity-vs-vade-for-m365)
- [NotifySecurity vs Egress Defend](https://cybersectools.com/compare/egress-defend-vs-notifysecurity)
- [NotifySecurity vs PhishingBox KillPhish](https://cybersectools.com/compare/notifysecurity-vs-phishingbox-killphish)

## Alternatives to each

- [See all GreatHorn Mailbox Intelligence alternatives](https://cybersectools.com/alternatives/greathorn-mailbox-intelligence)
- [See all NotifySecurity alternatives](https://cybersectools.com/alternatives/notifysecurity)

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Source: https://cybersectools.com/compare/greathorn-mailbox-intelligence-vs-notifysecurity

For AI agents: each product above has its own Markdown page (add .md to its URL, for example https://cybersectools.com/tools/greathorn-mailbox-intelligence.md). Every CybersecTools shortlist is listed at https://cybersectools.com/shortlists.md.

More on GreatHorn Mailbox Intelligence and NotifySecurity: funding, momentum, hiring and news, plus the full product and company record, are available through the Mandos MCP Server (paid plans), which connects to AI assistants: https://mandos.io/mcp?utm_source=cybersectools.com&utm_medium=compare-md