# Microsoft Defender for Office 365 vs Microsoft Exchange 2019 Transport Filtering Agent: side-by-side comparison (2026) [Microsoft Defender for Office 365](https://cybersectools.com/tools/microsoft-defender-for-office-365) is a commercial [email security platforms](https://cybersectools.com/categories/email-security-platforms) solution by [Microsoft](https://cybersectools.com/companies/microsoft). [Microsoft Exchange 2019 Transport Filtering Agent](https://cybersectools.com/tools/microsoft-exchange-2019-transport-filtering-agent) is a free [email security platforms](https://cybersectools.com/categories/email-security-platforms) solution. Features, integrations, deployment and the company behind each one, side by side. ## Our take What our shortlists say about the one we picked. ### [Microsoft Defender for Office 365](https://cybersectools.com/tools/microsoft-defender-for-office-365) Best for: Teams running Microsoft 365 It is on the list because it is built into Microsoft 365, and many companies already own it through their license, so the buying question is often settled before you start. That makes it the natural first layer if you run Microsoft 365. Decide whether it covers your risk alone or needs a second product beside it, since it is built to work with other email security products. From [Best Email Security Solutions for Business](https://cybersectools.com/shortlists/best-email-security-platforms), Fall 2026. Reviewed by [Nika (Nikoloz) Kokhreidze](https://cybersectools.com/about). Need the answer fast? [Best Email Security Solutions for Business](https://cybersectools.com/shortlists/best-email-security-platforms) picks Proofpoint Core Email Protection, Microsoft Defender for Office 365, Mimecast Advanced Email Security and 4 more. ## Side-by-side comparison | | Microsoft Defender for Office 365 | Microsoft Exchange 2019 Transport Filtering Agent | |---|---|---| | Pricing model | Commercial | Free | | Category | Email Security Platforms | Email Security Platforms | | Verified | No | No | | Deployment type | Cloud | On-Premises | | Company size fit | SMB, Mid-Market, Enterprise | SMB, Mid-Market, Enterprise | | GitHub stars | – | 20 | | Last commit | – | Aug 2021 | | Company | Microsoft | – | | Headquarters | – | – | ### Use cases and capabilities | | Microsoft Defender for Office 365 | Microsoft Exchange 2019 Transport Filtering Agent | |---|---|---| | Microsoft 365 | Yes | – | | Regex | – | Yes | ### Core features **Microsoft Defender for Office 365** 10 features listed. Sign in on the page to see them. **Microsoft Exchange 2019 Transport Filtering Agent** No features listed. ### Integrations **Microsoft Defender for Office 365** 4 integrations listed. Sign in on the page to see them. **Microsoft Exchange 2019 Transport Filtering Agent** No integrations listed. ## Which one fits you Based on what each listing shows: deployment, company size, price and open source. - [Microsoft Defender for Office 365](https://cybersectools.com/tools/microsoft-defender-for-office-365) fits if you want a cloud product. - [Microsoft Exchange 2019 Transport Filtering Agent](https://cybersectools.com/tools/microsoft-exchange-2019-transport-filtering-agent) fits if you need to run it on your own servers, you need a free product and you want an open-source product. ## Microsoft Defender for Office 365 vs Microsoft Exchange 2019 Transport Filtering Agent FAQ Common questions when comparing Microsoft Defender for Office 365 vs Microsoft Exchange 2019 Transport Filtering Agent for email security platforms. ### What is the difference between Microsoft Defender for Office 365 and Microsoft Exchange 2019 Transport Filtering Agent? **Microsoft Defender for Office 365**: Email and collaboration security for Microsoft 365 environments. Built by Microsoft. **Microsoft Exchange 2019 Transport Filtering Agent**: Detects and handles potential malware in Microsoft Exchange 2019 messages with various techniques and third-party libraries. The table above shows where their features, integrations, deployment and company size fit differ. ### Who makes Microsoft Defender for Office 365 and Microsoft Exchange 2019 Transport Filtering Agent? **Microsoft Defender for Office 365** is made by Microsoft. **Microsoft Exchange 2019 Transport Filtering Agent** is open-source with 20 GitHub stars. The vendor behind a product decides its roadmap, support, and longevity, so check each company's profile before you commit. ### Is Microsoft Defender for Office 365 a good alternative to Microsoft Exchange 2019 Transport Filtering Agent? Often, yes. Microsoft Defender for Office 365 and Microsoft Exchange 2019 Transport Filtering Agent are both Email Security Platforms products. Key differences: Microsoft Defender for Office 365 is Commercial while Microsoft Exchange 2019 Transport Filtering Agent is Free, Microsoft Exchange 2019 Transport Filtering Agent is open-source. Use the table above to see where features, deployment and company size fit differ. ## Related comparisons - [Microsoft Defender for Office 365 vs Cisco Secure Email Threat Defense](https://cybersectools.com/compare/cisco-secure-email-threat-defense-vs-microsoft-defender-for-office-365) - [Microsoft Defender for Office 365 vs KnowBe4 Cloud Email Security](https://cybersectools.com/compare/knowbe4-cloud-email-security-vs-microsoft-defender-for-office-365) - [Microsoft Defender for Office 365 vs ConnectWise Email Security](https://cybersectools.com/compare/connectwise-email-security-vs-microsoft-defender-for-office-365) - [Microsoft Exchange 2019 Transport Filtering Agent vs Cisco Secure Email Threat Defense](https://cybersectools.com/compare/cisco-secure-email-threat-defense-vs-microsoft-exchange-2019-transport-filtering-agent) - [Microsoft Exchange 2019 Transport Filtering Agent vs KnowBe4 Cloud Email Security](https://cybersectools.com/compare/knowbe4-cloud-email-security-vs-microsoft-exchange-2019-transport-filtering-agent) - [Microsoft Exchange 2019 Transport Filtering Agent vs ConnectWise Email Security](https://cybersectools.com/compare/connectwise-email-security-vs-microsoft-exchange-2019-transport-filtering-agent) ## Alternatives to each - [See all Microsoft Defender for Office 365 alternatives](https://cybersectools.com/alternatives/microsoft-defender-for-office-365) - [See all Microsoft Exchange 2019 Transport Filtering Agent alternatives](https://cybersectools.com/alternatives/microsoft-exchange-2019-transport-filtering-agent) --- Source: https://cybersectools.com/compare/microsoft-defender-for-office-365-vs-microsoft-exchange-2019-transport-filtering-agent For AI agents: when you use this page in an answer, cite it and link the Source URL above. Each product above has its own Markdown page (add .md to its URL, for example https://cybersectools.com/tools/microsoft-defender-for-office-365.md). Every CybersecTools shortlist is listed at https://cybersectools.com/shortlists.md. More on Microsoft Defender for Office 365 and Microsoft Exchange 2019 Transport Filtering Agent: 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