Terms of Service

Lockstep (“we”, “us”, “our”) is operated from the United Kingdom by:

• Jonathan Lockett trading as Lockstep
• 54 Croft Street, Farsley, Leeds, UK, LS28 5HA
• lockstepchemistry@gmail.com

These terms of service (the “Terms”) are the agreement between you and us covering your use of the Lockstep website, practice problems, drawing canvas and grading (together, the “Service”).

By creating an account you accept these Terms. If you do not accept them, do not create an account. You can reach us at lockstepchemistry@gmail.com, and we aim to reply within five business days.

You need to be at least 13 to hold an account. If you are under the age at which you can enter a contract where you live, you may only use the Service with a parent or guardian's permission, and only they may take out a paid subscription.

An account is personal to you. You are responsible for keeping your sign-in details secure and for what happens under your account, and you may not share it with, sell it to, or transfer it to anyone else.

Signing up costs nothing and does not ask for a payment card. The free plan opens 3 problems, with step-by-step grading on up to 3 of them and 2 graded submissions on each - a first attempt, and one revision after you have read the feedback - so you can see exactly how the grading works before spending money.

We may change what the free plan includes. What you get for paying is set out at the point you pay, and we will not reduce a paid subscription without the notice described in section 14.

• Price. There are two plans, priced in US dollars:
  • Monthly. $12 every month. You choose which one at checkout.
  • Semester. $40 every 4 months, which works out at $10.00/month. You choose which one at checkout.
  Both plans include exactly the same features; the only difference is how often you are billed. We price in US dollars because most of our students are in the United States; if your card is in another currency, your bank converts it and may add its own fee, which we do not control. Any tax we are required to collect is shown at checkout before you pay, and the total you are shown there is the total you are charged.
• It renews automatically. Billing starts when you complete checkout, and the same amount is charged to the same payment method again at the end of each billing period, on the same date. On the monthly plan that is every month; on a longer plan it is that much later, so the next charge may arrive some months after you last thought about it. There is no end date and we do not ask you to confirm each renewal. Your subscription continues, and you keep being charged, until you cancel it as described in section 5. Whichever plan you are on, the amount and the renewal date are shown on the Billing page and in the Stripe billing portal.
• No minimum term. You are not locked into a contract length and there is no fee for cancelling.
• Payment. Payments are taken by Stripe, our payment processor. We never see or store your full card details. You confirm that the payment method you use is yours, or that you have permission to use it.
• Failed payments. If a renewal payment fails, Stripe will retry it. If it keeps failing, access to paid features may be suspended and the subscription may be cancelled. Cancelling that way does not itself create a debt for the period that went unpaid.
• Fair use of grading. Grading a drawing is the one part of the Service with a real cost each time it is used, so a subscription covers up to 300 graded drawings in any 30-day period. That is ten a day, every day, and sits well above any normal course load - it is here to stop an automated loop or a shared account, not to ration your practice. Everything else, including multiple choice and reading explanations, is uncapped. If you reach the ceiling and you are genuinely studying, email lockstepchemistry@gmail.com and we will sort it out rather than leave you stuck.

• You can cancel at any time, without giving a reason and without a fee, from Billing → Manage subscription, which opens the Stripe billing portal. It takes a couple of clicks and needs no contact with us. If you would rather email lockstepchemistry@gmail.com, we will do it for you.
• What cancelling does. It stops the next renewal. You keep full access until the end of the billing period you have already paid for, and your account then returns to the free plan. We do not refund or apportion the remainder of a period already under way, except where section 6 says otherwise.
• Your work is not deleted. Cancelling leaves your account and your progress intact, so resubscribing picks up where you left off. If you want the account and its data deleted instead, email lockstepchemistry@gmail.com and we will delete it.

• Your first payment is refundable for 14 days. If you subscribe for the first time and Lockstep is not what you wanted, email lockstepchemistry@gmail.com within 14 days of that first charge and we will refund it in full. You do not need to give a reason. Access ends when the refund is made.
• Renewals are not refunded. The renewal date and amount are shown on the Billing page from the day you subscribe, and it is up to you to cancel before a renewal you do not want. A renewal that is charged because you did not cancel in time is not refunded.
• When the Service has not worked. If Lockstep was substantially unavailable, or grading was not functioning, for a meaningful part of a period you paid for, contact us and we will refund or credit a fair proportion of that period.
• Otherwise, subscription fees are not refundable once a billing period is under way, and we do not refund periods you simply did not use. This does not affect the rights the law gives you as a consumer, which are described in section 7 and which we cannot take away.
• How refunds are paid. Refunds go back to the original payment method through Stripe. Banks usually take five to ten business days to show them.
• How to ask. Email lockstepchemistry@gmail.com from the address on your account, with the date and amount of the charge. We aim to answer within five business days.

We are a UK business, so UK consumer law governs what we sell. You also keep the mandatory consumer protections of the country you actually live in. Nothing in these Terms reduces either of those, and where anything here conflicts with them, they win.

If you are in the UK or the EEA, you have a legal right to withdraw from a contract like this one within 14 days of entering it, without giving a reason. Where a digital service starts immediately, that right can normally be cut short once supply has begun. We do not rely on that for your first payment - section 6(a) gives you a full refund on request within 14 days regardless, so you do not have to work out which rule applies to you. Email lockstepchemistry@gmail.com and we will refund it.

If you are in the United States, federal and state law give you rights over subscriptions that renew automatically, including that the terms of renewal be disclosed clearly before you pay and that cancelling be as straightforward as signing up was. Both are how Lockstep is built: the renewal terms are set out next to the Subscribe button, and cancelling is a couple of clicks on the Billing page with no need to contact us, phone anyone or explain yourself. Nothing in these Terms waives a right your state gives you.

Wherever you are, you have rights if a service is not provided with reasonable care and skill, or is not as described. If Lockstep is not what we said it is, tell us.

We may change the subscription price. If we do, we will email you at least 30 days before the new price applies to you, and it only takes effect at your next renewal after that notice. If you do not want to pay the new price, cancel before that renewal and you will never be charged it.

While using Lockstep, you agree not to:

• share, resell or give others access to your account;
• scrape, bulk-download, republish or redistribute the problems, explanations or mechanisms;
• use the content to build, train or evaluate a competing product, model or dataset;
• work around the free-tier limits or the paywall, including by creating multiple accounts to get more free grading;
• submit drawings automatically or in bulk, or otherwise deliberately load the grading service beyond normal study use;
• upload anything unlawful, infringing or abusive through the drawing canvas; or
• attempt to break, probe or interfere with the Service or anyone else's use of it.

We may suspend or close an account that does these things. Where we close an account for a serious or repeated breach, we may do so without refunding the rest of the current period.

Lockstep is a practice tool, meant to be used while you study. Using it during an exam or quiz, or on graded work where outside help is not permitted, is likely to breach your institution's rules, and that is your responsibility rather than ours.

• Problems are drafted with AI and reviewed by a human before they are published. Grading of the mechanisms you draw is done by an AI vision model, without a human checking each result.
• Questions written by your instructor. An assignment in a class can include questions your instructor wrote themselves. Those are checked and approved by them, not reviewed by us, and are marked against the answer they gave. If you think one is wrong, raise it with your instructor.
• Grading can be wrong. It may mark a correct mechanism wrong, or miss a mistake in one that is wrong. Feedback is study guidance, not an authoritative assessment, and it is not a substitute for your instructor, your course materials or your own judgment. Check anything that matters against them.
• We do not promise any particular grade, exam score or other outcome from using Lockstep.
• If you think a grade or an explanation is wrong, please tell us at lockstepchemistry@gmail.com. Reports of bad grades are how the grader gets better.

• The problems, explanations, mechanisms, text, design and software are owned by us or our licensors and protected by copyright. For as long as you have an account, whether you are paying or not, you have a personal, non-exclusive, non-transferable licence to use whatever your plan opens to you for your own study, and no other rights are granted. A subscription changes how much is open to you; it does not change what you may do with it.
• You keep ownership of what you draw and submit. You give us the permission we need to process it in order to grade it and run the Service.
• To grade a mechanism, the drawing is sent to Anthropic's Claude API. The image itself is not stored. What we keep is the verdict, the score, the per-step results and the feedback text, so that your progress page can show you how you are doing.
• Questions you write for your classes. If you write your own questions to set in a class, you keep ownership of them and you are responsible for them: that they are accurate, and that you have the right to use anything you put in them. You give us the permission we need to store them, to show them to students in your classes, to grade answers to them, and to send what you write to Anthropic's Claude API when you ask us to draft an answer key. We do not add them to our own bank or show them to anyone outside your classes. The acceptable-use rules in section 9 apply to them as they do to anything else you submit.
• We may use anonymised, aggregated information about how the Service is used to improve it.

To run the Service we store your account identifier, your subscription status and payment identifiers, and a record of the problems you have attempted and how you did on them. Accounts and sign-in are handled by Clerk, payments by Stripe, and grading by Anthropic; each processes that data so that we can provide the Service to you.

We are the data controller for that information, and we handle it under UK data protection law. You can ask us for a copy of what we hold, ask us to correct it, or ask us to delete your account and the data attached to it, at any time, by emailing lockstepchemistry@gmail.com. Records we are required to keep for tax or accounting reasons, such as invoices, are kept for as long as the law requires.

If you think we have handled your data badly, please tell us first. You can also complain to the UK Information Commissioner's Office, or to the data protection regulator where you live.

Our Privacy Policy sets all of this out in full: what is collected, the legal basis for each use, who else handles it, how long it is kept, and how to exercise your rights.

We work to keep Lockstep available, but we cannot promise uninterrupted access: maintenance, faults, and outages at the services we depend on all happen. We may add, change or remove features as the product develops, and problems may be added to or withdrawn from the bank.

If we make a change that materially reduces what a paid subscription gives you, we will tell you at least 30 days beforehand, and you may cancel and ask for a refund of the unused part of the period you have paid for.

We may suspend or close an account that breaches these Terms, that has not paid, or where we are required to by law. If we close your account for reasons of our own, rather than for anything you have done, we will refund the unused part of the period you have paid for. Where we close it for a serious or repeated breach, section 9 governs instead.

If we ever discontinue Lockstep entirely, we will give reasonable notice and refund paid time that you have not been able to use.

To the fullest extent the law allows, the Service is provided “as is” and “as available”, and we do not warrant that the content is free of errors or that the Service will meet your requirements.

Nothing in these Terms excludes or limits our liability for death or personal injury caused by negligence, for fraud or fraudulent misrepresentation, or for anything else that cannot lawfully be excluded. If you are a consumer, your statutory rights are not affected.

Subject to section 16, and to the extent the law allows: we are not liable for indirect or consequential loss, for lost grades, opportunities or profits, or for loss of data; and our total liability to you for all claims arising in any twelve-month period is limited to the greater of the amount you paid us in the twelve months before the claim arose, or fifty US dollars.

We may update these Terms as the Service changes. If a change materially affects your rights or your subscription, we will email you at least 30 days before it takes effect, and it will apply from your next renewal after that. Continuing to use Lockstep after that point means you accept the new Terms; if you would rather not, cancel before then. The date at the top of this page always shows when it was last changed.

These Terms are governed by the law of England and Wales, and the courts of England and Wales have jurisdiction over any dispute arising from them.

If you are a consumer living somewhere else - in the United States, or anywhere outside the UK - that choice does not take away the protection of the mandatory consumer laws of the country and state you live in, and it does not stop you bringing proceedings in your local courts. Choosing English law settles which law fills the gaps; it does not override rights your own law gives you and will not be used to argue that it does.

Before starting formal proceedings, please email lockstepchemistry@gmail.com. Almost everything is quicker and cheaper to sort out that way, and we would rather refund someone than argue with them.

These Terms are the whole agreement between you and us about the Service. If any part of them is found unenforceable, the rest continues to apply. Our not enforcing a term straight away does not waive it. We may transfer our rights and obligations if the business is sold, without reducing your rights under these Terms; you may not transfer yours without our consent.

Questions about these Terms, cancellations, refunds or anything else: lockstepchemistry@gmail.com.