diff --git a/README.md b/README.md
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@@ -770,6 +770,7 @@ Table of Contents
    * [taskade.com](https://www.taskade.com/) — Real-time collaborative task lists and outlines for teams
    * [taskulu.com](https://taskulu.com/) — Role based project management. Free up to 5 users. Integration with GitHub/Trello/Dropbox/Google Drive
    * [testlio.com](https://testlio.com/) — Issue tracking, test management and beta testing platform. Free for private use
+   * [terrastruct.com](https://terrastruct.com/) — Online diagram maker specifically for software architecture. Free tier up to 4 layers per diagram.
    * [todoist.com](https://todoist.com/) — Collaborative and individual task management. Free, Premium and Team plans are available. Discounts provided for eligible users.
    * [trello.com](https://trello.com/) — Board-based project management. Unlimited Personal Boards, 10 Team Boards.
    * [ubertesters.com](https://ubertesters.com/) — Test platform, integration and crowdtesters, 2 projects, 5 members