Privacy policy

This is Offset App’s privacy policy. It explains what personal data we collect when you use our website (offsetapp.co.uk) and our app (app.offsetapp.co.uk), how we use it, and your rights. Topics include:

1. Who we are
2. What data do we collect?
3. How do we collect your data?
4. How will we use your data?
5. Who we share your data with
6. How do we store your data, and for how long?
7. Information about your clients
8. What are your data protection rights?
9. Cookies and similar technologies
10. Visitor data
11. Privacy policies of other websites
12. Changes to our privacy policy
13. How to contact us

1. Who we are

Offset is provided by Murdo McDermid, a sole trader trading as Offset App, of Tribe Porty, 19 Windsor Place, Edinburgh, EH15 2AJ ("we", "us"). We are the controller of the personal data described in this policy, except for the information about your clients covered in section 7. We are registered with the Information Commissioner's Office (ICO) under registration number ZC259920. You can contact us about anything in this policy at support@offsetapp.co.uk.

2. What data do we collect?

Offset App collects the following data:

• Account details: your email address, and your password, which is stored only in scrambled (hashed) form, so no one, including us, can read it. We also keep basic records of when you signed up and signed in, and the IP address used. Each time your account loads rooflight product data, we record the date, time and IP address, to protect our product library from misuse.
• Your calculations: everything you enter into a calculation, such as the project name, site address, planning reference, the assessor's name, notes and building figures.
• Practice details: your practice's name, who belongs to it, and who owns it.
• Team invites: if a practice owner invites you to join their practice, your email address, which practice invited you, who sent the invite and when. We use it to email you the invite and to check it's you when you accept it.
• Referrals: if you create an account through someone's referral link, a record that they referred you, when you signed up and subscribed, and any account credit they received as a result. If you refer people, we keep the same records, but we only ever show you how many people signed up and subscribed through your link, never who they are. We never email the people you refer.
• Subscription and billing records: your plan, its status and renewal date, and the reference numbers Stripe gives your account and subscription. Stripe holds your card details. We never see or store your full card number.
• Messages you send us: support emails, and bug reports and manufacturer requests sent from inside the app. These include your email address, your message, and, for bug reports, the page you were on and your browser and device type.
• Demo bookings: the name and email address you give when you book a demo.

You need to give us an email address to create an account, because we can't provide the service without one. Everything else you put into a calculation is up to you.

3. How do we collect your data?

You directly provide Offset App with most of the data we collect. We collect data and process data when you:

• Register to use the application.
• Use the app, including saving calculations and setting up or joining a practice.
• Subscribe to a paid plan (through Stripe's secure checkout).
• Contact the support email, or send a bug report or manufacturer request from the app.
• Book a demo.

If a practice owner invites you to join their practice, they give us your email address so that we can send you the invite.

We do not currently collect any analytics data.

4. How will we use your data?

Offset App uses your data for the purposes below. The law requires us to have a lawful basis for each one, and the table shows which basis applies.

We do not use your data for marketing, we do not sell it, and we do not make decisions about you by purely automated means.

5. Who we share your data with

Your practice. If you join a practice, its owner can see your email address, your role and the date you joined, so they can manage the team. Everyone in the practice can see and edit the calculations saved in it. Other members cannot see your email address. If a practice owner invites you, they can see the email address they invited and when they sent the invite, until you join or the invite is cancelled or expires.

We use a small number of trusted providers to run Offset. They handle your data only on our instructions and under contracts that require them to protect it:

• Supabase: our database, sign-in system and server functions. Your data is stored in the EU (Frankfurt), and our server functions run in London.
• Netlify: hosts our website and app (see section 10).
• Stripe: processes payments and holds your card details. Stripe also uses some payment information for its own purposes, such as preventing fraud, under its own privacy policy.
• Resend: sends emails from the app, such as sign-up confirmations, password resets and team invites, and passes bug reports and manufacturer requests to our support inbox.
• IONOS: hosts our support email inbox.
• Google: runs the calendar booking page used for demo bookings.

Some of these providers are based in the United States, or use staff or systems there. Where personal data is transferred outside the UK, it is protected by safeguards recognised under UK data protection law. These are the UK–US "data bridge" for certified companies, or the International Data Transfer Agreement or Addendum approved by the Information Commissioner's Office (ICO). You can ask us for more detail.

We will only share your data with anyone else where the law requires it, for example with HMRC.

6. How do we store your data, and for how long?

Offset App stores your account details, calculations and practice details securely online with Supabase, in the EU. Data is encrypted in transit and at rest, and access is restricted so that you, and members of your practice, can see only your own practice's calculations.

We keep your data for these periods:

• Account details, calculations and practice details: while your account is open. If you ask us to delete your account, we will delete this data within 30 days.
• Subscription and billing records: for as long as UK tax law requires. This is currently at least five years after the 31 January Self Assessment deadline for the tax year concerned.
• Support emails, bug reports, manufacturer requests and demo bookings: up to one year after we last hear from you about them.
• Records of access to the rooflight product library: 12 months.
• Team invites: until 30 days after the invite expires. Invites expire 7 days after they're sent, and a cancelled invite is deleted straight away.
• Referral records: while the account that was referred is open. Where account credit was given, the record of that credit is also kept with the subscription and billing records above.

7. Information about your clients

Calculations can contain information about other people, such as a site address. For that information, the architect or practice using Offset decides what to enter and why, so they are the controller. We process it only on their behalf, under section 13.3 of our Terms of Service. If you are a client with a question about your data, please contact the practice that prepared the calculation first. We will help them respond.

8. What are your data protection rights?

Offset App would like to make sure you are fully aware of all of your data protection rights. Every user is entitled to the following:

• The right to access – You have the right to request Offset App for copies of your personal data.
• The right to rectification – You have the right to request that Offset App correct any information you believe is inaccurate. You also have the right to request Offset App to complete the information you believe is incomplete.
• The right to erasure – You have the right to request that Offset App erase your personal data.
• The right to restrict processing – You have the right to request that Offset App restrict the processing of your personal data, under certain conditions.
• The right to object to processing – You have the right to object to Offset App’s processing of your personal data, under certain conditions.
• The right to data portability – You have the right to request that Offset App transfer the data you have given us to you, or to another organisation, in a commonly used format, under certain conditions.

Making a request is free. We will respond within one month. For a complex request, we may extend this by up to two further months, and if so we will tell you why within the first month.

If you are unhappy with how we have handled your data, please tell us first so we can try to put it right. You also have the right to complain to the Information Commissioner's Office, the UK's data protection regulator, at ico.org.uk/make-a-complaint or on 0303 123 1113.

9. Cookies and similar technologies

Offset App does not use cookies, and does not use any tracking, advertising or analytics technology.

When you sign in to the app, your browser keeps a sign-in token and your currently selected practice in its local storage, so that you stay signed in between visits. This is strictly necessary to provide the service you have asked for, so it does not need your consent. The sign-in token is removed when you sign out. Our homepage stores nothing on your device, and loads nothing from other websites unless you choose to: if you play the intro video, it plays from YouTube in its privacy-enhanced mode, and YouTube (Google) may then set its own cookies, covered by Google's privacy policy.

If you subscribe, Stripe's checkout page sets its own cookies, for example to prevent fraud. These are covered by Stripe's cookie policy.

10. Visitor data

This website and our app are hosted by Netlify. Netlify collects personal data when you visit them, including:

• Information about your browser, network and device
• Web pages you visited prior to coming to this website
• Your IP address

Netlify needs the data to run this website, and to protect and improve its platform and services. Netlify analyses the data in a depersonalised form.

11. Privacy policies of other websites

Offset App’s website contains links to other websites. Our privacy policy applies only to our website, so if you click on a link to another website, you should read their privacy policy.

12. Changes to our privacy policy

Offset App keeps its privacy policy under regular review and places any updates on this web page. If we make a significant change, we will also tell account holders by email or in the app. This privacy policy was last updated on 14 October 2026.

13. How to contact us

If you have any questions about Offset App’s privacy policy, the data we hold on you, or you would like to exercise one of your data protection rights, please do not hesitate to email us or write to us at Offset App, Tribe Porty, 19 Windsor Place, Edinburgh, EH15 2AJ.