1. Introduction

Cambridge Quantum Computing (“CQC”, “we”, “us” or “our”) is a world leading independent quantum computing software company. CQC respects your privacy and is committed to safeguarding the privacy of information provided to us.

Software sometimes includes functionality to collect data about how the software is used or performing (“Telemetry Data”). Telemetry Data is often collected through a “phone home” mechanism built into the software itself. Each end user deploying the software is typically presented with the choice to opt-in to share statistical data with the developers of the software.

This Telemetry Data Policy (“Telemetry Data Policy”) explains how we may collect, store and use Telemetry Data that is obtained from the telemetry feature for our proprietary “t|ket>” software, also referred to as ‘pytket’ in this Telemetry Data Policy.

This telemetry feature calls back to CQC servers with information which helps us understand how our users use our software libraries. It may also collect diagnostic telemetry data which is integral to the improvement of our software. If you have any questions about this, please contact

This Telemetry Data Policy provides you with certain information that must be provided under the General Data Protection Regulation ((EU) 2016/679) (GDPR) and the local data protection law.

Data collected

The telemetry feature will collect the following Telemetry Data:

Telemetry Data - Description

Value Example

Telemetry ID – A random ID


Pytket related software versions – version of pytket installed and pytket plugins

pytket 0.6.1



Processor – Processor Make

Intel, AMD

Python implementation

CPython, Pypy …

Python version

3.6, 3.7 …


Linux, Windows, Java …

System version

Windows 10, Windows XP …

System release


C API version

Crash reports – technical information, such as error and usage statistics, which help our developers understand what is happening inside the product code if the software crashes

Users will be provided with a randomly generated telemetry ID which will be used to identify the system that is then stored in the user’s configuration file. The telemetry feature will not collect any Personally Identifiable Information (PII). For the avoidance of doubt, CQC maintains that it will still treat all the Telemetry Data collected (listed above) as though it is personal data.

What the Data will be Used for

In accordance with GDPR, the Telemetry Data will be used for:

  • determining how many people are using and downloading pytket

  • determining what kind of systems pytket is typically run on so we know where to target support and features

  • support for reporting faults and errors automatically in a way that can be collected and aggregated - i.e., after a release we can see if a lot of errors start to occur.

3. How we store the Data

The Telemetry Data is stored in a managed PostgreSQL server hosted in Azure Web Services, where it is stored with a timestamp as an event.

4. Your Rights

In accordance with the provisions of GDPR, we inform you that you can exercise your rights of access, rectification, erasure, right to be forgotten, opposition, data portability and limitation of processing directly with CQC.

To facilitate the exercise of these rights, you may send a message with your request to this effect, indicating name, surname and e-mail address to the following e-mail address:

5. Security

We take reasonable steps to hold information securely in electronic or physical form and to prevent unauthorised access, use, modification or disclosure. We require our third-party data storage providers to comply with appropriate information security industry standards. All partners and staff and third-party providers with access to confidential information are subject to confidentiality obligations.

The transmission of information via the internet is not completely secure. We cannot guarantee the security of your data transmitted to our online services; hence, any transmission is at your own risk.

6. Acceptance of this Telemetry Data Policy

Any user who installs and uses CQC’s proprietary ‘t|ket>’ software (the “End User”) ACKNOWLEDGES AND AGREES TO HAVE READ AND UNDERSTOOD this Telemetry Data Policy, the content of which constitutes the entire agreement between the End User and CQC regarding the use and processing of the End User’s Telemetry Data. The End User expressly agrees to be bound by the terms of the present Telemetry Data Policy, in its entirety and scope, without exception to any of its provisions.

CQC reserves the right to update and make changes to the Telemetry Data Policy even without prior notice to the End User. It is the End User’s responsibility to review the amended Telemetry Data Policy.

7. Contact and Further Information

Should you have any questions about this Telemetry Data Policy, or want to submit a written complaint to us about how we handle your Telemetry Data, please contact us at:

Attention: Data Protection Officer

Cambridge Quantum Computing Limited

32 St. James’s Street



The United Kingdom

Telephone: +44 (0) 203 301 9331


If you make a privacy complaint, we will respond to let you know how your complaint will be handled. We may ask you for further details, consult with other parties and keep records regarding your complaint.

Last updated: The Pytket Telemetry Data Policy was last updated on 30 November 2020.