Terms of Service

1. Who you are contracting with

Fault Tolerant is operated by Harjaspreet Singh, an individual seller based in India. In these terms "we", "us" and "our" mean Harjaspreet Singh. By creating an account, accessing the site, or continuing to use the service, you agree to these terms. If you are using the service on behalf of an organisation, you confirm you have authority to bind that organisation. If you are using it as an individual, you confirm you are of legal age to enter into a contract in your country.

You are contracting with an individual, not a registered company. If Harjaspreet Singh later registers a business to operate Fault Tolerant, the seller named in these terms will be updated to that registered entity and the "last updated" date will change.

2. What the service is

Fault Tolerant is an online practice platform for system design interviews. It provides a diagramming workspace, a library of practice problems, timed mock interviews, learning material, puzzles, and AI-assisted feedback on the designs you produce. It is an educational tool. It does not guarantee any interview outcome, job offer, or assessment result.

3. Your account

You must provide accurate registration information and keep it up to date. You are responsible for keeping your credentials confidential and for all activity that happens under your account. Tell us promptly at support@faulttolerant.dev if you believe your account has been accessed without your permission.

4. Acceptable use

You must not:

• use the service for any unlawful purpose, or in breach of any applicable law or regulation;
• commit fraud, send spam, or impersonate another person;
• infringe anyone's intellectual property or other rights;
• upload malware, probe or interfere with our security, or attempt unauthorised access to any system;
• scrape, bulk-download, resell, or redistribute our problems, learning content, or AI outputs;
• reverse engineer the service or circumvent usage limits, credit limits, or paywalls;
• share your account so that multiple people use a single subscription.

5. Licence and intellectual property

We retain all ownership of the service, including software, problem sets, learning content, branding, and documentation. Subject to these terms, we grant you a limited, non-exclusive, non-transferable right to use the service for your own interview preparation within the plan you have selected.

You keep ownership of the designs, diagrams, notes, and other content you create. You grant us a limited licence to host, store, and process that content solely to operate and improve the service, including sending the relevant parts of it to our AI providers to generate feedback.

6. AI-generated content

Parts of the service use AI models to generate interviewer questions, hints, and design feedback. AI output can be incomplete, outdated, or wrong. It is for educational purposes only and is not professional, engineering, legal, financial, or career advice. You are responsible for your prompts, for verifying any output before relying on it, and for ensuring you have the rights to any content you enter. You must not use the AI features to generate unlawful, hateful, deceptive, or infringing content, or to attempt to jailbreak or extract the underlying models. We may filter, restrict, or refuse output and may suspend accounts that misuse these features.

If you believe content on the service infringes your rights, contact support@faulttolerant.dev and we will review and, where appropriate, remove it. Repeat infringement results in account termination.

7. Plans, credits, and payment

Paid plans are sold as monthly or annual subscriptions and include a monthly allowance of AI credits. Credits reset at each renewal and do not roll over. Upgrading adds the new plan's credits immediately; downgrading takes effect at the next renewal. A subscription you cancel stays active until the end of the period already paid for. If a renewal payment fails, paid access ends and the account returns to the Free plan until payment is resolved.

Our order process is conducted by our online reseller Paddle.com. Paddle.com is the Merchant of Record for all our orders. Paddle provides all customer service inquiries and handles returns. Payment, billing, tax, cancellation, and refund mechanics are governed by Paddle's Buyer Terms. See our Refund Policy for refunds.

8. Availability

We work to keep the service available and accurate, but we do not guarantee uninterrupted or error-free performance. Features may change, and maintenance or third-party outages (including AI provider outages) may interrupt access.

9. Suspension and termination

We may suspend or terminate your access for material breach of these terms, non-payment, security or fraud risk, or repeated or serious policy violations. You may stop using the service at any time and cancel your subscription. On termination, your right to use the service ends; you may request an export of your saved designs within 30 days, after which we may delete your content.

10. Warranties and liability

To the fullest extent permitted by law, the service is provided "as is" and we disclaim all implied warranties, including merchantability and fitness for a particular purpose. We are not liable for indirect, consequential, or special damages, including lost profits, lost data, or lost opportunities. Our aggregate liability is limited to the fees you paid in the twelve months before the claim. Nothing in these terms excludes liability for fraud, death, or personal injury where that exclusion is not permitted by law.

You agree to indemnify us against claims arising from your content, your unlawful use of the service, or your breach of these terms.

11. General

These terms are governed by the laws of India, and the courts of India have jurisdiction over disputes, without affecting mandatory consumer rights in your country of residence, including rights you cannot lawfully be contracted out of under India law. You may not assign these terms without our consent; we may assign them in connection with a merger or acquisition. Neither party is liable for delays caused by events beyond its reasonable control. We may update these terms and will change the "last updated" date; continued use after an update means you accept it.

12. Contact

Questions or complaints: support@faulttolerant.dev. Fault Tolerant is provided by Harjaspreet Singh, an individual seller, India. Billing and refund enquiries are handled by Paddle, our Merchant of Record.