Codecheck is an anonymous, author-friendly autograder. It is optimized for simple programming assignments that provide practice and build confidence.

Why CodeCheck?

  1. You don't need to register for authoring questions. Your students don't need to register for participating. Nobody needs to ask anyone for permission.
  2. Authoring a programming problem is delightfully simple. Provide a solution. Use comments to mark the parts that your students should fill in. Use comments to indicate test inputs. Upload and distribute a URL. Check out the authoring guidelines for details.
  3. NEW Make assignments with multiple programming problems and activities from my Big Java/Big C++/Python for Everyone books. More information at the assignment guidelines.

Try It Out

Check out this example. If your report looks like this, keep on trying until all test cases pass.

For additional assignments and problems, follow the links below.

Frequently Asked Questions

Privacy Statement

CodeCheck collects the following data:

The data is used to display assignments to students, to collect problem submissions from students, and to display submissions to instructors. Instructors can see submissions for the assignments that they create.

Assignments are stored indefinitely. Submissions may be periodically removed.

The data is stored in virtual machines and databases of commercial cloud providers. There is a risk of that data to become public. You should not include any private information in anything that CodeCheck stores, other than the IDs and keys generated by CodeCheck. In particular, do not provide your name, college ID, email address, or any password.

Log files may contain IP addresses from browser requests. Log files are stored for a few days and may be analyzed to fix problems with the service.

CodeCheck uses browser cookies to manage session state, and to store the “CodeCheck ID” and the IDs of recently worked problems. You can use the site without any cookies, but then you need to manually provide the CodeCheck ID and the IDs and edit keys for all submissions.

CodeCheck does not use third-party cookies. CodeCheck does not send any data to third parties.

To exercise your “right to be forgotten”, send an email to with the private URL of the assignment, programming problem, or submission that you wish to have removed.


Thanks to Sunita Rajain and Tyler Wasniowski from San José State University for developing a predecessor to the assignments feature.

Thanks to Chaz Chang from San José State University for implementing the “edit URL” feature that enables instructors to edit problems. Previously, an instructor had to make a new problem to fix any issues with a problem.

Thanks to Greta Yu from Evergreen Valley High School for implementing multiple editable areas. In older versions of CodeCheck, the entire code was in a single text area and it was not possible to protect code from being edited.

Thanks to Anthony Trinh and Hien Vu from San José State University for providing text areas for inputting and editing problems. Previously, it was only possible to upload a zip file.