Last updated 30 October 2026

Pywr for Azure DevOps (the “Licensed Application”) is licensed to you by Stefano Simoncelli, trading as Pywr Tools (“Licensor”, “we”, “us” or “our”), only under the terms of this licence agreement. “You” means the organisation that installs the Licensed Application and the people in it who use it.

By installing the Licensed Application from the Visual Studio Marketplace, or by using it, you accept this licence agreement. If you do not accept it, do not install or use the Licensed Application.

Microsoft runs Azure DevOps and the Visual Studio Marketplace but is not a party to this licence agreement. We alone are responsible for the Licensed Application and its content. We reserve all rights not expressly granted to you.

Pywr for VS Code is not covered by this agreement. It has its own licence.

1. The application

The Licensed Application is an extension for Azure DevOps Services. It shows the changes that a pull request makes to a Pywr water resource model, as changed components and on the schematic, and lets reviewers comment and vote in the browser.

2. Scope of licence

2.1 Each Azure DevOps organisation may use the Licensed Application free of charge for 30 days, starting the first time one of its users opens it (the “Trial”).

2.2 After the Trial, the organisation needs a licence. A licence is a subscription for a number of seats, bought by card from the Model reviews page or by invoice. The price is the one shown at checkout or on the invoice.

2.3 Each seat lets one user of the organisation use the Licensed Application. A user takes a seat the first time they open it. A user who has not opened it for 30 days frees the seat for another user. When all seats are taken, further users cannot use the Licensed Application until a seat is freed or more seats are bought.

2.4 You may use the Licensed Application only within the organisation the licence was bought for and only for your own business purposes. We may move a licence to another organisation of yours on request.

2.5 You may not, and may not let anyone else:

• copy, modify, translate or create derivative works of the Licensed Application;
• rent, lease, lend, sell, sublicense or redistribute it;
• reverse engineer, decompile or disassemble it, or try to derive its source code, except where the law allows it despite this restriction;
• remove, change or hide any copyright or licence notice in it;
• get around the Trial or the seat limit, for example by sending made-up user IDs to the licence server;
• use it to build a competing product.

2.6 The Licensed Application includes third-party software, each under its own licence, listed in its third-party notices. Those licences apply to that software.

3. Technical requirements

3.1 The Licensed Application works only with Azure DevOps Services. It does not work with Azure DevOps Server.

3.2 It needs a supported web browser and an internet connection, because it checks the licence with our licence server each time it opens.

3.3 We try to keep the Licensed Application working with the current version of Azure DevOps Services. Microsoft can change Azure DevOps at any time, and we cannot guarantee that a change will not affect the Licensed Application.

4. Maintenance and support

4.1 We will make reasonable efforts to answer support requests and to fix reported defects, but we do not promise a response time. How to get support is described in our support policy.

4.2 Microsoft has no obligation to provide maintenance or support for the Licensed Application.

5. Your content

5.1 The models, pull requests, comments and votes you create or view with the Licensed Application (“Your Content”) stay in your Azure DevOps organisation. We do not receive them and we claim no ownership of them.

5.2 You are responsible for Your Content and for making sure you have the right to use it. You must not use the Licensed Application to post content that is unlawful, infringes someone else’s rights, or harasses or abuses anyone.

5.3 If you send us suggestions or other feedback about the Licensed Application, we may use them for any purpose without paying you.

5.4 We process personal information as described in our privacy policy.

6. Payment and renewal

6.1 A subscription renews automatically at the end of each period until it is cancelled. You can change the number of seats or cancel from the Stripe customer portal, or by emailing us for a licence bought by invoice.

6.2 A cancellation takes effect at the end of the period already paid for. Fees already paid are not refundable, except as set out in section 8 or where the law requires.

6.3 Invoices must be paid by their due date. If a subscription is not paid, it ends and its seats stop working.

7. Liability

7.1 Nothing in this agreement limits or excludes our liability for death or personal injury caused by our negligence, for fraud or fraudulent misrepresentation, or for any other liability that cannot be limited or excluded under the law of England and Wales.

7.2 Subject to 7.1, we are not liable for any loss of profit, revenue, business, contracts or anticipated savings, loss or corruption of data, or any indirect or consequential loss, whether in contract, tort (including negligence) or otherwise.

7.3 Subject to 7.1, our total liability arising from or in connection with this agreement is limited to the fees you paid for the Licensed Application in the 12 months before the event that gave rise to the claim.

7.4 The Licensed Application helps people review changes to a model. It does not check whether a model or its results are correct. You remain responsible for the decisions you make with it.

8. Warranty

8.1 We warrant that the Licensed Application is free of spyware, trojan horses, viruses and other malware when we publish it, and that it works substantially as described in its documentation.

8.2 This warranty does not apply if the Licensed Application has been modified without our permission, used in a way this agreement does not allow, or affected by a change or fault outside our control, such as a change to Azure DevOps or a browser.

8.3 Please report any defect to us by email without undue delay, with the details we need to reproduce it.

8.4 If we confirm the defect, we will either fix it or provide a version that does not have it. If we cannot do either within a reasonable time, you may cancel your subscription and we will refund the fees paid for the remaining part of the current period.

8.5 Except as set out in this section, and to the extent the law allows, the Licensed Application is provided “as is”, without any other warranty, express or implied, including any warranty of merchantability, fitness for a particular purpose or non-infringement.

9. Product claims

We, not Microsoft, are responsible for any claim by you or a third party relating to the Licensed Application or your use of it, including product liability claims, claims that it does not meet a legal or regulatory requirement, and claims under consumer protection, privacy or similar laws.

10. Legal compliance

You confirm that you are not located in a country subject to UK, EU or US sanctions or embargoes, and that you are not on any UK, EU or US list of prohibited or restricted parties.

11. Contact information

For questions, complaints or claims about the Licensed Application, email Stefano Simoncelli at support@pywrtools.dev.

12. Termination

12.1 This agreement lasts until you or we end it. You can end it at any time by uninstalling the Licensed Application and cancelling your subscription.

12.2 Your rights under this agreement end automatically, without notice, if you break any of its terms. We may also end it by giving you 30 days’ notice by email, in which case we will refund the fees paid for any period after the end date.

12.3 When this agreement ends, you must stop using the Licensed Application and uninstall it from your organisation. Sections 5, 7, 9, 14 and 15 continue to apply.

13. Third-party terms

You must comply with Microsoft’s terms for Azure DevOps and the Visual Studio Marketplace when you use the Licensed Application. Payments by card are processed by Stripe under its own terms.

14. Intellectual property rights

14.1 The Licensed Application and all intellectual property rights in it belong to Stefano Simoncelli and his licensors. Pywr is an independent open-source project and does not make the Licensed Application.

14.2 If a third party claims that the Licensed Application, or your use of it in line with this agreement, infringes their intellectual property rights, we, not Microsoft, are responsible for investigating, defending, settling and discharging the claim.

15. Applicable law

This agreement and any dispute arising from it are governed by the law of England and Wales, excluding its conflict of law rules. The courts of England and Wales have exclusive jurisdiction.

16. Miscellaneous

16.1 If any term of this agreement is or becomes invalid, the rest of the agreement stays in force. The invalid term is replaced by a valid one that comes as close as possible to its purpose.

16.2 Changes to this agreement are valid only in writing. We may update this agreement by publishing a new version on this page. For an existing subscription, the new version applies from its next renewal, and we will email you about important changes beforehand.

16.3 This agreement is the whole agreement between you and us about the Licensed Application, and replaces any earlier agreement about it. A purchase order you send us does not change it.