VisuStruct — Visual Structogram Editor

Visual structogram editor for Nassi-Shneiderman diagrams — plan algorithms by structure, not syntax first.

The open-source Java desktop app and the SwiftUI app for iPad and Mac with Apple silicon share one .visustruct format. Drag-and-drop editing, clean UI, three interface languages: English, German, Portuguese.

The up-to-date Java edition — source and releases — is maintained only at github.com/code4teaching/VisuStruct.

Java app for Windows, macOS & Linux

Java desktop: palette, tabbed canvas, export (e.g. PNG). Needs a Java runtime.

VisuStruct Java edition on the desktop: window with menus, German-labelled structure blocks (statement, branch, loops, switch), and a Nassi-Shneiderman diagram with nested control flow. — Java desktop (sample screenshot). Current builds and downloads: GitHub releases (Downloads section).

SwiftUI app for iPad & Mac

The structogram editor for your iPad and your Mac.

VisuStruct on Mac: main window with a Nassi-Shneiderman structogram, elements list on the left, and statement inspector at the bottom. — SwiftUI on Mac — same workflow on iPad.

Key features

Simple, intuitive interface — the focus stays on logic.
Develop the algorithm first, then think about syntax.
One .visustruct format — Java on the desktop and SwiftUI on iPad & Mac, same project file.

Algorithm first, then code

Start with logic and flow — your algorithm. Then express the same structure with syntax, in whatever programming language you choose — step by step and easy to follow.

Get VisuStruct

Java app (desktop)

Open source (MIT). Windows, macOS, Linux. Development and current releases live only in the linked GitHub repository.

Latest release (GitHub) Direct to the app

iPad & Mac (Apple silicon)

SwiftUI · iPad & Apple silicon Mac · tabs, share, print · 1.1 (App Store).

Apple App Store

Privacy policy – use of VisuStruct

VisuStruct does not collect personal data and, in how it is built, supports GDPR-compliant use. Your structograms and .visustruct files stay on the user’s device. There is no scraping, central storage, or tracking of your teaching content by VisuStruct. Processing happens where it belongs — locally with the learner. For schools, that usually means less uncertainty than with many cloud services, because diagram data is not sent to the app publisher.

Contact

Holger Sebastiao is a computer science teacher. Classroom practice feeds into VisuStruct. VisuStruct was built to help people understand and develop algorithms. It is a tool for teachers and learners.

More projects—mostly focused on teaching and education—are on my website at www.sebastiao.org (mostly in German for now).