Introduction to VTT QX

Published

September 12, 2025

VTT QX is a cloud platform that allows users access to VTT’s quantum computers. Users can run quantum circuits, manage their jobs, see previous results, and view specific device metrics through the dashboard. It also provides utilities for user, project, and access management. You can currently access the service at qx.vtt.fi.

Projects

Each user can be a member of one or more projects within VTT QX. Projects provide access to devices. The list of available devices per project is shown in the project details view.

If a device is not part of any project that the user is a member of, it will be shown as unavailable in the dashboard (indicated by a closed lock icon).

Devices available for a Project

Project Administrator

Each project has an admin. The project administrator can perform the following actions:

  • Close the project
  • Change the project description
  • Remove members from the project

Project Lifecycle

A project has a defined lifetime. When the project reaches the end of its lifetime, its status changes from “Active” to “Closed”. The project lifetime can be extended by contacting support. When a project is in the “Closed” state, job results can still be retrieved, but no new jobs can be submitted.

Project Quota

Projects are associated with a project quota, which can be viewed in the project details view. The project usage is reset at the beginning of each month.

When a project runs out of quota, jobs will be rejected with the following message:

Insufficient project quota

Please reach out to support if the project quota needs to be modified for your project.

There are two types of project quota:

  1. QPU seconds per month
  2. Booking minutes per month

QPU seconds is calculated based on actual time taken to execute the circuits on the processor. Booking minutes track reserved device access time.

For detailed information about how usage is calculated, including special handling during booking periods, see the Usage Calculation documentation.

Failed jobs do not increase the monthly project usage, and job submissions to the “Demo” device are not billed. The project usage is reset at the beginning of each month.

Queue Limits

The system enforces queue limits to ensure fair resource allocation:

  • Device Queue Limit: Each device can have a maximum of 500 pending jobs
  • Project Queue Limit: Each project can have a maximum of 100 pending jobs across all devices

If you reach either limit, new job submissions will be rejected until existing jobs complete and free up queue space.