Legal
Effective 6 November 2026
Data Cleaning Exercises is an online service for learning and practising data cleaning, available at datacleaningexercises.com. In this policy, “we”, “us” and “our” mean UMRATECH, which operates Data Cleaning Exercises and is responsible for your personal data as the data controller.
This policy explains what personal data we collect when you visit the website, create an account, practise exercises, use the AI tutor, buy a plan or contact us, and what choices and rights you have. It does not cover websites we link to.
Account information. When you create an account we receive your email address and, if you provide them, your name and profile picture. If you sign in with Google, we receive your name, email address and profile picture from Google. Passwords are handled by our sign-in provider; we never see or store them.
Learning records. For each answer you check while signed in, we record the exercise, the track (visual, SQL or Python), whether it passed, how many of the test datasets matched, how long the check took and when it happened. From these we keep your progress: which exercises you've started and completed.
Teams and classrooms. If you join an organization by invitation, its owners, admins and instructors can see your name, email address, role, when you joined and the status of its assignments (not started, in progress, completed, completed late), and can download that as a CSV file. They cannot see your drafts, code, notes or tutor conversations. When you leave or are removed, they no longer see your status; your own progress stays in your account.
Certificates. When you claim a certificate of completion, we store the name you enter for it, the date and a certificate ID. The certificate has its own web address so that you can share it and others can verify it; anyone with that link can see the name, date and what was completed. Certificate pages are not listed in search engines.
Your work. When you check an answer, the pipeline or code you wrote is sent to our servers so it can be run and compared with the expected result. We don't keep a copy of it after the check; we keep only the result described above. Drafts you haven't submitted are saved in your browser on your device, not on our servers.
AI tutor requests. When you ask the tutor for help, we send the exercise rules, a few rows of the exercise's fictional dataset, your current draft, any error message shown to you and your question to our AI model provider to produce the answer. We don't store the question or the answer. We record how many tutor turns you've used and how much processing each used, to apply your monthly allowance.
Payment information. When you buy a plan, our payment processor collects your card or other payment details directly. We never receive your full card number. We receive and keep a customer reference, the plan you bought, its price, status, renewal and end dates, and your billing country where needed for tax.
Messages to us. When you email us or use the contact form we receive your email address, your name if you give it, the topic and your message, and whether you were signed in. We send you an automatic confirmation and reply by email.
Technical and usage information. Like most websites, our hosting provider processes your IP address, browser type, device type, the pages requested and timestamps to deliver the site and protect it against abuse. We also measure aggregated page views and site performance with privacy-friendly analytics that don't use cookies and don't identify you across websites.
Advertising measurement. We advertise on Google. When you arrive from one of our Google ads and allow it, the Google tag sets cookies that remember the ad click, and tells Google Ads when you create an account or buy a plan: the plan price, a transaction reference and, if you're signed in, your email address, which the tag hashes (turns into an irreversible code) in your browser before sending. Google uses this to match the sign-up or purchase to the ad click. We don't send your name, your learning records or your code. We tell Google not to use this data to personalise ads.
Where data protection law such as the UK or EU GDPR applies, we rely on these legal bases:
| Purpose | Legal basis |
|---|---|
| Creating and securing your account, signing you in | Performing our contract with you |
| Running and checking your answers, saving progress, showing your dashboard, issuing certificates | Performing our contract with you |
| Providing the AI tutor and applying your allowance | Performing our contract with you |
| Taking payment, managing subscriptions, issuing refunds | Performing our contract with you |
| Keeping billing and tax records | Legal obligation |
| Answering your messages and support requests | Our legitimate interest in helping you, or our contract with you |
| Preventing abuse, fraud and attacks; enforcing fair use and rate limits | Our legitimate interest in keeping the service safe and available |
| Measuring and improving the site with aggregated analytics | Our legitimate interest in improving the service |
| Measuring which of our Google ads lead to sign-ups and purchases | Your consent in the UK, the EEA and Switzerland; our legitimate interest in measuring our advertising elsewhere |
We don't use your personal data for automated decisions that have legal or similarly significant effects on you. Answer checks compare your result with the exercise's rules; they only affect your progress in the course.
We don't send marketing emails unless you've asked for them, and every such email will include a way to stop them.
Our service providers may process data in countries other than yours, including the United States. Where data protection law requires it, we rely on safeguards such as the European Commission's standard contractual clauses and the UK addendum, or an adequacy decision, to protect data transferred outside the UK or the European Economic Area.
| Data | Kept for |
|---|---|
| Account, learning records and progress | Until you delete your account. They are then deleted promptly. |
| Certificates | Until you delete your account; the verification link then stops working. |
| Code and pipelines submitted for checking | Only while the check runs. |
| AI tutor questions and answers | Not stored by us. Monthly usage counts are kept with your account. |
| Billing records | As long as tax and accounting law requires, usually up to seven years, even after account deletion. They are then separated from your contact details. |
| Messages to us | Up to two years after your request is resolved. |
| Security and access logs | Typically up to 30 days, longer only when needed to investigate abuse. |
| Drafts in your browser | On your device until you clear your browser's site data. |
Depending on where you live, you may have the right to access your personal data and get a copy of it, correct it, delete it, restrict or object to how we use it, and receive it in a portable format. Californian residents have the right to know, delete and correct personal information and not to be discriminated against for using these rights.
We respond within one month, or sooner where the law requires. If you're not satisfied, you can complain to the data protection authority where you live or work. In the UK that is the Information Commissioner's Office.
We encrypt data in transit, limit access to personal data to the people and systems that need it, keep secrets out of the code that runs submitted answers, and run every submitted answer in an isolated environment with no access to other learners' data or to the internet. No system is perfectly secure; if a breach affects your personal data, we'll tell you and the authorities as the law requires.
Data Cleaning Exercises is not directed at children. You must be at least 16 years old, or the minimum age of digital consent where you live if that is higher, to create an account. Buying a plan requires the age of majority where you live or the involvement of a parent or guardian. If you believe a child has given us personal data, please contact us and we'll delete it.
The exercises use fictional data, and you never need to enter real personal or confidential data to use Data Cleaning Exercises. Please don't paste real customer records, passwords, card numbers or other sensitive information into exercises, the AI tutor or the contact form.
We'll update this policy when our practices change and show the new effective date at the top. If a change materially affects how we use your personal data, we'll tell you in advance by email or with a notice when you sign in.
For privacy questions or requests, email support@umratech.com or use the contact form and choose “Privacy or my data”. Please don't include sensitive information in your first message.