You can recognize grammar and vocabulary without using them independently.
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Writing
Grammar, vocabulary, structure, register and coherence become visible in one text.
Stop studying random grammar.
Start learning from your own mistakes.
Your focus this week
Welcome back!
German · Current level: A2 · Target: B2
Your goalWrite something to unlock your full potential
This week's target1 writing
Next recommended actionStart with your first writing
Learning Coach
Analyze your first writing and FluencyOS will show your most useful focus for this week.
Main Focus This WeekNo writing analyzed yet
Analyze your first writing to generate your weekly focus.
Today: Start with the next useful step
Your progress
0Current Streak0Writings Completed0Exercises Completed0New Words Learned
Activity calendar
This month
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Recent Writings
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Writing analysis
Grading scale
Rubric criteria, from weakest to strongest:
Critical focus: main bottleneck; blocks level performance.
Needs attention: recurring issue that noticeably affects quality.
Developing: partially controlled, but still inconsistent.
Competent: works for the level, with some limitations.
Strong: clearly controlled and effective.
Excellent: achieved or above the selected level.
Grammar/Vocabulary summary:
Excellent: achieved or clearly above the selected level.
Acceptable: okay for the level, but not fully achieved yet.
To be improved: several relevant issues; needs focused work.
Grammar-
Vocabulary-
Level
Original
Correction
Type
Why
Severity
This week's focusYour main focus area
Open a topic to practise the exercises selected from your writing.
Grammar exercises
Strengthen your weak areas with targeted practice.
Vocabulary upgrades generated from your latest writing.
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Choose the monthly plan that fits your learning rhythm.
Current plan: Free
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Basic grammar practice
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Premium9.99€/month
Everything you need to make consistent progress and prepare for exams with confidence.
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Exam-aligned feedback (CEFR)
Writing history & analytics
Why learners choose Premium
🎯Practice consistently
Write, practise and improve every day with guided learning.
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Privacy Policy
Last updated: June 2026
1. Who is responsible for FluencyOS?
FluencyOS is operated by [Your legal name or company]. Contact: [your contact email].
2. What data do we collect?
We collect account data such as email address, profile data such as name, target language, level, goal and learner age group, and learning data such as writings, AI corrections, exercises, vocabulary suggestions and usage limits.
3. Why do we use this data?
We use this data to create and manage your account, personalize language learning, generate AI corrections and exercises, enforce plan limits, provide support, manage subscriptions and keep the service secure.
4. AI processing
User texts may be processed by AI providers to generate corrections, exercises and vocabulary. Do not submit sensitive personal information, confidential documents or information about third parties unless you have the right to do so.
5. Payments
Payments and subscription management are processed by Stripe. FluencyOS does not store full card numbers.
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We use Supabase for authentication and database storage, Vercel for hosting and serverless backend, Stripe for payments and an AI provider for language processing.
7. How long do we keep data?
We keep account and learning data while your account is active or as needed to provide the service, comply with legal obligations, resolve disputes and enforce our agreements.
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You may request access, correction, deletion, restriction or portability of your personal data, and you may object to certain processing. Contact us at [your contact email].
Terms and Conditions
Last updated: June 2026
1. Service
FluencyOS is a language learning tool that helps users practice writing, review AI-generated corrections, complete exercises and study vocabulary.
2. Account
You are responsible for keeping your login details secure and for the content you submit to FluencyOS.
3. Plans and limits
Free and Premium provide different access levels to writing feedback, exercises, vocabulary practice and learning analytics. FluencyOS may apply fair-use protections to keep the service stable and secure.
4. AI output
AI-generated corrections, levels, explanations and exercises may contain mistakes. FluencyOS is an educational support tool and does not certify official language levels.
5. Payments and cancellation
Paid plans are billed monthly through Stripe. Users can manage or cancel subscriptions through the customer portal when payments are enabled.
6. Acceptable use
Do not use FluencyOS to submit illegal, harmful, confidential or sensitive content, or to infringe the rights of others.
7. Changes
We may update these terms as the service develops. Continued use of the service means you accept the updated terms.
Legal Notice
Last updated: June 2026
Owner
[Your legal name or company] [Tax ID, if applicable] [Business address, if applicable] [your contact email]
Website
FluencyOS provides a web-based language learning service with AI-assisted writing corrections, exercises and vocabulary practice.
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The FluencyOS name, interface, software, design and content are owned by or licensed to the service owner. User writings remain the user's own content.
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FluencyOS is provided as an educational tool. We work to keep it available and accurate, but we cannot guarantee uninterrupted service or error-free AI output.
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Last updated: June 2026
Current cookie use
FluencyOS currently uses only technical storage needed for login, security, app configuration and temporary cache. These are necessary for the app to work.
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How to control cookies
You can delete or block cookies and local storage from your browser settings. Some parts of the app may stop working if technical storage is disabled.