Terms of Service

These Terms of Service ("Terms") govern your access to and use of The Missing Workbook (the "Service"), an English vocabulary dictionary and study product operated by h15n Ventures ("h15n Ventures," "we," "us," or "our") at missingworkbook.com. By accessing or using the Service, creating an account, or purchasing a paid plan, you agree to these Terms.

If you do not agree to these Terms, do not use the Service.

1. Eligibility

You must be at least 13 years old to use the Service. If you are under 18, you represent that your parent or legal guardian has reviewed and agreed to these Terms on your behalf.

If you use the Service on behalf of an organization, you represent that you have authority to bind that organization to these Terms.

2. The Service

The Missing Workbook is a structured English-learning product. It includes:

• A searchable English vocabulary dictionary with CEFR levels, IPA pronunciation, senses, examples, synonyms, antonyms, and etymology
• Roots, affixes, phrases, idioms, collocations, grammar and usage references, pronunciation references, and public-domain reading material
• Spaced-repetition study tools, review history, mastery tracking, activity views, and related learning workflows
• Paid Pro features, including study access beyond the free level and deeper atlas/study surfaces

The Service is an educational tool. It is not a school, accredited course, professional testing service, immigration service, legal service, or guarantee of exam results, employment results, or language proficiency.

3. Accounts and Security

Some features require an account. You agree to provide accurate account information, keep your credentials secure, and notify us if you believe your account has been accessed without permission.

You may sign in with an email/password account or, where available, Google Sign-In. You are responsible for activity under your account unless the activity was caused by our failure to use reasonable security measures.

We may suspend or terminate accounts that violate these Terms, are used for abuse, or create security, operational, or legal risk for the Service.

4. Acceptable Use

You agree not to:

• Use the Service for unlawful, harmful, deceptive, or abusive purposes
• Attempt to gain unauthorized access to the Service, user accounts, servers, or connected systems
• Interfere with or disrupt the Service, including through excessive automated requests, denial-of-service activity, or attempts to bypass rate limits
• Scrape, crawl, copy, bulk download, or redistribute the Service's content or data without our prior written permission, except for normal search-engine indexing and ordinary personal use
• Reverse engineer, probe, or exploit the Service except as permitted by law or a written security policy from us
• Upload or submit content that is illegal, infringing, hateful, harassing, sexually exploitative, or intended to harm others
• Misrepresent your identity, affiliation, or relationship with h15n Ventures
• Use the Service to build a competing dataset or commercial product without permission

5. Learning Content

We work to make the dictionary, examples, etymologies, pronunciation notes, grammar notes, and study data useful and accurate. Language is full of edge cases, regional variation, dictionary disagreements, and changing usage. We do not guarantee that every entry, example, pronunciation, analysis, translation, or study recommendation is complete, current, or error-free.

Some etymology and explanatory content may be generated or assisted by software and then stored in the Service. Treat that material as a learning aid, not an authoritative source. If you find an error, please tell us.

6. User Content and Submitted Text

"User Content" means text, files, feedback, support messages, writing samples, analysis inputs, notes, or other material you submit to the Service.

You retain ownership of your User Content. You grant h15n Ventures a limited, non-exclusive, worldwide, royalty-free license to host, process, display, analyze, store, copy, and transmit User Content only as needed to operate, secure, support, and improve the Service.

Do not submit confidential, highly sensitive, or regulated information unless it is necessary for the feature you are using. Writing-analysis and reading-assist features are meant for ordinary learning material, not medical, financial, legal, or similarly sensitive documents.

You are responsible for having the rights needed to submit User Content. We may remove User Content that we believe violates these Terms or applicable law.

7. Our Intellectual Property and Third-Party Data

The Service, including its design, software, workflows, original explanations, curation, branding, and compiled datasets, is owned by h15n Ventures or its licensors and is protected by intellectual-property laws.

You receive a limited, revocable, non-transferable license to use the Service for personal learning and ordinary account use. These Terms do not transfer ownership of the Service or its content to you.

The Service may include public-domain, open-source, Creative Commons, or other third-party data and references. Those materials remain subject to their respective licenses and terms.

8. Paid Plans, Billing, Cancellation, and Refunds

Some features require a paid Pro plan. Payments are processed by Stripe. We do not store full card numbers on our servers.

By purchasing a paid plan, you authorize h15n Ventures and Stripe to charge the payment method you provide for the plan and price shown at checkout, plus any applicable taxes.

Subscription billing

• Monthly plan: billed each month until cancelled.
• Annual plan: billed each year until cancelled.

You can cancel a subscription from your billing settings at /billing when billing is available for your account. Cancellation stops future renewal charges. You keep paid access through the end of the billing period already paid.

Free tier and refunds

The free tier is your trial. The dictionary, search, pronunciation, etymology breakdowns, and free-level study tools are available before you upgrade.

Unless required by law or stated otherwise at checkout, payments are non-refundable. Monthly and annual subscriptions are not prorated after cancellation. Lifetime purchases are not refundable.

If there is a billing error, duplicate charge, account-access problem, medical emergency, or other unusually sympathetic situation, contact missingworkbook@h15n.com. We may resolve issues case by case at our discretion.

Price changes and failed payments

We may change prices or plan features. If a change affects an active subscription, we will provide notice before the change applies to a future renewal where required by law or by our payment provider's rules.

If a payment fails, Stripe may retry collection. If collection ultimately fails, your Pro access may revert to the free tier until payment is updated.

9. Third-Party Services

The Service uses third-party providers for functions such as payment processing, authentication, email delivery, hosting, analytics, and error monitoring. Your use of those third-party services may be governed by their own terms and privacy policies.

We are not responsible for third-party websites or services that we do not control.

10. Privacy

Our Privacy Policy explains what information we collect, how we use it, which providers we use, and how to contact us about data requests. Our Cookie Policy explains cookies and similar technologies.

11. Service Changes and Availability

We may add, change, limit, suspend, or discontinue features at any time. We try to keep the Service reliable, but we do not guarantee uninterrupted access, permanent availability, or preservation of every feature in its current form.

We may make maintenance, security, infrastructure, pricing, or product changes without advance notice when needed.

12. Disclaimer of Warranties

To the maximum extent permitted by law, the Service is provided "as is" and "as available," without warranties of any kind, whether express, implied, or statutory, including implied warranties of merchantability, fitness for a particular purpose, title, and non-infringement.

We do not warrant that the Service will be uninterrupted, secure, error-free, or that content, study recommendations, review intervals, learning estimates, or pronunciation and writing analyses will be accurate for your situation.

13. Limitation of Liability

To the maximum extent permitted by law, h15n Ventures, its operators, affiliates, service providers, and licensors will not be liable for indirect, incidental, special, consequential, exemplary, or punitive damages, or for lost profits, lost data, loss of goodwill, or service interruption arising from or related to your use of the Service.

To the maximum extent permitted by law, h15n Ventures' total liability for any claim relating to the Service will not exceed the greater of:

• The amount you paid to h15n Ventures for the Service in the 12 months before the event giving rise to the claim; or
• US $100.

Some jurisdictions do not allow certain limitations of liability. In those jurisdictions, the limitations apply only to the extent permitted by law.

14. Indemnification

You agree to defend, indemnify, and hold harmless h15n Ventures, its operators, affiliates, service providers, and licensors from claims, liabilities, damages, losses, and expenses, including reasonable attorneys' fees, arising from your misuse of the Service, violation of these Terms, violation of law, or User Content.

15. Termination

You may stop using the Service at any time. You may request account deletion by emailing missingworkbook@h15n.com.

We may suspend or terminate access if you violate these Terms, create risk for the Service or other users, or if we discontinue the Service.

After termination, provisions that by their nature should survive will survive, including intellectual-property provisions, warranty disclaimers, limitations of liability, indemnification, and payment obligations already incurred.

16. Changes to These Terms

We may update these Terms from time to time. The current version will be posted on this page. If changes are material, we will provide additional notice when reasonable, such as by email or in-product notice.

Continuing to use the Service after updated Terms take effect means you accept the updated Terms. If you do not agree, stop using the Service and cancel any paid subscription before the next renewal.

17. Governing Law and Disputes

These Terms are governed by the laws applicable to h15n Ventures and the Service, excluding conflict-of-law rules, except where your local law gives you non-waivable rights.

Before filing a claim, you agree to contact us at missingworkbook@h15n.com and give us a reasonable chance to resolve the dispute informally.

18. Contact

The Missing Workbook is operated by h15n Ventures. Questions about these Terms? Contact missingworkbook@h15n.com.