Terms of Service

01

What Particle Is

Particle is a personal productivity application — a focus timer, task planner, and sound environment designed to help you do meaningful work. The service is provided as a web application accessible at particle.day.

02

Your Account

• You need an account to use Particle. Authentication is handled by Clerk.
• One account per person. Shared or automated accounts are not permitted.
• You are responsible for keeping your login credentials secure and for all activity under your account.
• You must be at least 16 years old (or 13 outside the EU) to create an account.
• You must provide accurate information when creating your account.

03

Subscriptions and Payments

Particle offers two tiers:

• Free Tier — core focus timer and basic features, available at no cost
• Flow Subscription — advanced features including AI Coach, extended analytics, and premium sound environments

Payments for the Flow subscription are processed by Stripe. We never see or store your card details. Subscriptions renew automatically at the end of each billing period until cancelled. You can cancel anytime through Settings — your access continues until the end of the current billing period. Refunds are handled on a case-by-case basis; contact us at support@particle.day.

Pricing changes. Pricing may change over time. We will provide at least 30 days' advance notice of any change posted on this page and emailed to account holders. Changes will not retroactively affect a billing period already paid for; new pricing applies from the next renewal, giving you the option to cancel before it takes effect.

Founding Lifetime tier. The Founding Lifetime offer is a one-time payment for lifetime access to Flow, limited to the first 500 customers and offered only during the launch window announced on the pricing page. “Lifetime” refers to the lifetime of the Particle service, as defined in § 12 (Service Discontinuation).

04

Your Data, Your Ownership

Everything you create in Particle — tasks, sessions, notes, projects, intentions — belongs to you. We claim no intellectual property rights over your content. You can export your data at any time in machine-readable JSON format through Settings or the API.

The application itself — its code, design, sounds, illustrations, and brand — is our intellectual property, protected by copyright and other applicable laws. You may not reverse-engineer, decompile, copy, or create derivative works without written permission.

05

Acceptable Use

You agree to use Particle in good faith and for its intended purpose. You may not:

• Use the service for any unlawful purpose
• Attempt to gain unauthorized access to our systems or other users' data
• Interfere with or disrupt the service or its infrastructure
• Use automated tools (bots, scrapers) to access the service
• Resell or redistribute access to the service
• Use the AI Coach to generate harmful, abusive, or misleading content
• Circumvent usage limits or feature restrictions

06

AI Features Disclaimer

Particle includes AI-powered features, including the Coach, which provides productivity suggestions, reflections, and insights. These features are powered by third-party large language models.

• AI-generated content is not medical, therapeutic, psychological, or professional advice
• The Coach is a productivity companion — not a substitute for professional guidance
• AI responses may be inaccurate, incomplete, or inappropriate
• You should not rely on AI suggestions for important life, health, or financial decisions
• We are not liable for actions taken based on AI-generated content

07

Availability and Changes

We strive to keep Particle available and reliable, but we cannot guarantee uninterrupted access. We may perform maintenance, update features, or modify the service at any time. For significant changes that reduce functionality, we will provide reasonable notice.

We do not provide a guaranteed Service Level Agreement (SLA). Particle is operated on a best-effort basis. Free-tier users receive no uptime guarantee. Paid subscribers may rely on a target of 99% monthly uptime as a goal but not as a contractual commitment, and no service credits are offered for downtime. If sustained downtime affects a paid subscriber for more than 7 consecutive days, the subscriber may request a pro-rata credit at our reasonable discretion.

08

Closing Your Account

You can delete your account at any time through Settings. Upon deletion:

• Your personal data will be removed within 30 days per our Privacy Policy
• Active subscriptions will be cancelled immediately
• This action is permanent and cannot be undone

Your retention obligation for invoices you have issued. If you use the invoice-generation feature to issue invoices to your clients, you are the issuing Unternehmer under German tax law, and § 147 Abgabenordnung in conjunction with § 14b UStG requires you to retain a copy of each issued invoice for ten years from the end of the calendar year of issue. Particle is the tool you use to create them — it is not the Unternehmer, and the statutory retention duty rests with you, not with us.

Account deletion deletes all your invoice data. When you delete your account, we remove your user-generated invoices, their line items, VAT metadata, and frozen PDF archive copies from our systems within 30 days — the same deletion window as the rest of your data. We do not retain them against your wishes; your data is yours. Before you delete your account, use the audit export feature (a machine-readable JSON of every invoice you’ve issued, ready for handoff to your Steuerberater) so you can meet your own § 14b UStG retention obligation going forward. Once the account is deleted, the data is gone from our side; the legal duty to retain it for the ten-year window stays with you.

Particle’s own invoices to you (for your Particle subscription) are a separate matter: those are issued by PELKE EXTENDED DESIGN STUDIO and we retain them under our own § 14b UStG obligation, handled through Stripe. Account deletion does not affect that retention, which covers only our billing records of you as a customer.

We may suspend or terminate your access if you violate these terms or engage in conduct that harms the service or other users. We will tell you why and, where possible, give you an opportunity to remedy the situation before termination.

09

Limitation of Liability

The service is provided “as is” and “as available” without warranties of any kind, whether express or implied, including but not limited to implied warranties of merchantability, fitness for a particular purpose, and non-infringement.

To the maximum extent permitted by law:

• Our total liability shall not exceed the amount you paid us in the 12 months preceding any claim
• We are not liable for indirect, incidental, special, consequential, or punitive damages
• We are not liable for loss of data, profits, or business opportunities
• We are not liable for any actions taken based on AI-generated content

Nothing in these terms excludes or limits liability for death, personal injury caused by negligence, fraud, or any other liability that cannot be excluded under applicable law.

10

Indemnification

You agree to indemnify and hold Particle harmless from any claims, damages, or expenses arising from your use of the service in violation of these terms or applicable law.

11

Right of Withdrawal (EU / German Consumers)

If you are a consumer within the European Union, you generally have the right to withdraw from distance contracts within 14 days without giving any reason (§ 312g BGB, Art. 9 Consumer Rights Directive 2011/83/EU).

Waiver for immediately-started digital services: For the Flow subscription, you expressly request that we begin providing the service immediately upon purchase. By completing your purchase, you acknowledge that you thereby waive your right of withdrawal once the subscription period has commenced, in accordance with § 356 para. 5 BGB and Art. 16(m) of the Consumer Rights Directive.

This waiver applies from the moment the subscription is activated. If you have not yet used any Flow features, you may still request a refund by contacting us at support@particle.day within 14 days of purchase. We will evaluate such requests on a case-by-case basis.

The right of withdrawal does not apply to free accounts or to the free tier of the service.

12

Service Discontinuation

If we discontinue Particle, in whole or in part, we commit to the following:

Notice.We will provide at least 60 days' written notice (via email and a notice on the service) before discontinuation takes effect.

Monthly subscribers. We will not charge the next monthly billing cycle. Your current paid month continues until its scheduled end.

Annual subscribers. We will refund the unused portion of any prepaid annual subscription on a pro-rata basis, calculated as (full months remaining at the discontinuation date / 12) × the annual fee paid. Refund is issued to the original payment method within 30 days of discontinuation.

Lifetime tier.“Lifetime” refers to the lifetime of the Particle service, not the lifetime of the customer. We commit to operating the service for at least 24 months from the date of any individual lifetime purchase. If the service is discontinued within that 24-month period, lifetime customers receive a pro-rata refund of ((24 − months delivered) / 24) × the price paid. After 24 months of operation following purchase, no refund is owed for discontinuation in good faith.

Data export. We will keep the service available in read-only mode for at least 30 days after the discontinuation date so you can export your data. Export tools (CSV, JSON) remain available throughout this period.

Insolvency exception. In the event of insolvency, government action, or similar involuntary shutdown beyond our control, refund obligations are subject to applicable insolvency law and may not be fulfillable in full.

13

Force Majeure

We are not liable for any failure or delay in performance caused by events beyond our reasonable control, including but not limited to acts of nature, war, terrorism, pandemic, government action, internet or hosting provider outages, vendor terminations of essential third-party services (Stripe, Clerk, Supabase, OpenRouter, Vercel, Anthropic, Google), or critical security incidents. In such events we will use reasonable efforts to restore the service or, if restoration is not feasible, apply Section 12 (Service Discontinuation).

14

Beta and Preview Features

Particle may release features marked as “beta”, “preview”, “experimental”, or similar. These features are provided “as is” without any warranty or support commitment, may be modified or removed at any time without notice, and are explicitly excluded from any service-level expectation, refund calculation, or liability claim under these Terms.

15

Changes to These Terms

We may update these terms occasionally. For material changes, we will notify you at least 14 days in advance via email or in-app notification. If you disagree with updated terms, you can close your account before they take effect. Continued use of the service after the effective date constitutes acceptance of the new terms.

16

Governing Law and Disputes

These terms are governed by the laws of the Federal Republic of Germany. Any disputes arising from or relating to these terms or the service shall be subject to the exclusive jurisdiction of the courts in Germany.

For EU consumers: you may also use the European Commission's Online Dispute Resolution platform. We are willing to participate in out-of-court dispute resolution before a consumer arbitration board.

17

Severability

If any provision of these terms is found to be unenforceable, the remaining provisions will continue in full force and effect. The unenforceable provision will be modified to the minimum extent necessary to make it enforceable.

18

Get in Touch

Questions about these terms? We're at legal@particle.day.