STACK | Online assessment

STACK is the world-leading open-source online assessment system for mathematics and STEM. It is available for Moodle, ILIAS and as an integration through LTI.

Why use STACK?


Algebraic answers

Students can answer with algebraic expressions, like \(x^2+y\), and answers are graded based on mathematical properties.


Separate validation and assessment

Answers are validated before they are marked, so students are not penalised for poor programming skills.

Thinking person

Specific feedback

Students are given feedback that refers to their specific answer and mistake, as if marked by hand.



STACK can generate random questions so students are shown different variants of questions, and can repeat quizzes with new variants.

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Language support

STACK is available in most European languages and many more, including Hebrew and Japanese.



STACK is free to use and is developed by educators like yourself. Contributions are welcomed and encouraged.

Learn more    Get Started

Who uses STACK?

STACK is used by universities, commercial partners, developers and more, in over 15 countries. To read about the many ways STACK is used around the world, please visit our Case Studies page.

Training and Events

We host regular training workshops and a yearly international STACK conference. To sign up for one of our future events, or see materials from our past events, go to our Training and Events page.


STACK has extensive documentation available locally through GitHub and online. To get started, see the Authoring quick start or the self-contained "Getting started with STACK" guide.