Theorymaker

This free, open-source web tool was created by Steve Powell as a rapid, logic-first way to build Theories of Change.

Theorymaker was updated in 2026. The updated version is a complete rewrite of the original tool, adding AI-assisted design and a more robust layout engine.

The information provided was supplied by Steve Powell.

Authors and their affiliation

Steve Powell,  Causal Map Ltd.

Key features of Theorymaker

Theorymaker is a web app designed to generate diagrams for Theories of Change, logframes, and causal maps. It's light, for when you don't want to bother with either a full-on Theory of Change / M&E system or with a full-on diagramming app. The background info and help files are here.

• Free: The tool is completely free to use, and you don't need to register.
• Hybrid Creation: You can build and refine your diagram in three ways simultaneously:
  • AI Chat: Just ask the built-in (optional) AI to build, expand, or tweak your logic.
  • Click-to-Edit: Click directly on nodes or links to style them or add new elements.
  • MapScript Editor: Edit the underlying text language for total control.
• "Opinionated" Auto-Layout: Theorymaker automatically finds the best positions for your boxes and connectors. It isn't a freeform drag-and-drop tool; it handles the layout so you can focus on the logic.
• Styling & Grouping: Easily group nodes into phases, regions, or stakeholder blocks.
• URL-Based Saving: The entire diagram is created and stored in your browser. As you type or edit, the URL updates with exactly the information needed to recreate your diagram. You can bookmark the link or share it to allow others to recreate the exact same diagram instantly.
• Templates & Local Storage: Load example maps to get started or save your work directly to your browser's local storage.Undo/Redo: Integrated with your browser’s back/forward buttons.
• Flexible Exports: Save your diagrams as graphic files or use the Plain Link feature for a portable, shareable version of your work.

How have you used or intend on using this resource?

As the creator of this resource, I have often used it to sketch out theories of change, logframes etc for evaluation plans and reports. It is good not to have to worry about layout, dragging and dropping connectors etc, as the layout it produces automatically is usually OK. Because the layout is automated, I can add a new "Impact" or "Assumption" mid-meeting without having to manually move twenty other boxes to make room.  And I can save a link to the online diagram and make changes and additions really quickly. Most people using it at the moment are making small-to-medium sized sketches rather than fully-fledged theories or logframes.

Why would you recommend it to other people?

• Speed: Even without using the AI, it is significantly faster than making diagrams with tools like PowerPoint.
• Logic first: It forces you to think about the variables and the links (the actual theory) without having to worry about layout and formatting.
• Interoperability: If you need a high-end graphic for a formal report, you can "sketch" the logic here first, save it as an .svg file and send it to a designer.