Terms of Use

Kaizen — Terms of Use Last updated: 07/01/2026 Canonical URL: https://vertexhub.ai/kaizen/terms

This is a parallel-language version of the Portuguese original above; in case of conflict for users in Brazil, the Portuguese version governs.

1. Acceptance#

These Terms of Use ("Terms") govern your use of the Kaizen app ("App"), made available by VertexHub do Brasil Ltda, a company registered in Brazil under CNPJ 68.119.875/0001-40, headquartered at Avenida Engenheiro Luiz Carlos Berrini, 1748, Cidade Monções, São Paulo, SP, CEP 04571-000, Brazil ("we," "us"). By downloading or using the App, you agree to these Terms and to our Privacy Policy (Part 3). If you do not agree, do not use the App. To subscribe to Kaizen Pro, you must be of legal age to contract in your jurisdiction, or have the consent of a legal guardian.

These Terms are an agreement between you and us — not between you and Apple. Apple's standard Licensed Application End User License Agreement also applies as a supplement (available at https://www.apple.com/legal/internet-services/itunes/dev/stdeula/); in case of conflict, whichever is more protective of the consumer prevails.

2. License#

We grant you a personal, limited, non-exclusive, non-transferable license to use the App on Apple devices that you own or control, in accordance with the App Store's usage rules. You may not redistribute, resell, reverse-engineer, or commercially exploit the App, except where the law permits.

3. Kaizen Pro subscription#

The App offers a free tier and a paid, auto-renewable subscription, Kaizen Pro (ai.vertexhub.kaizen.pro.monthly).

• Free tier: classic Sudoku, the daily challenge, deterministic hints, and up to 3 new puzzles per day in practice mode.
• Kaizen Pro: unlimited puzzles in practice mode, the conversational AI tutor, and all variants (Killer, Thermo, Sandwich, and randomly-generated shape modes).
• Price and duration are shown in the App at the time of purchase, in your local currency, and may vary by region.
• Automatic renewal: the subscription renews automatically at the end of each period and is charged to your App Store account, unless canceled at least 24 hours before the end of the current period.
• Management and cancellation: manage or cancel at any time in Settings > [your name] > Subscriptions on your Apple device. Cancellation takes effect at the end of the period already paid for — no prorated refund. Until then, you keep Pro access; after that, the app automatically reverts to the Free plan. If a free trial period is offered, any unused portion is forfeited upon purchasing a subscription, where applicable.
• Payments, refunds, and restoring purchases are processed by Apple, under the App Store's terms, not by VertexHub. Restore Purchases is available within the App.

4. On-device AI (tutor and coach)#

Kaizen's tutor and coach generate educational guidance using artificial intelligence that runs on your device (Apple Foundation Models) — not an external AI service, and VertexHub does not receive or process your conversations with the tutor. The tutor explains logical deductions already computed by a deterministic engine (it does not itself "solve" the Sudoku); this content is intended for educational and entertainment purposes, does not constitute professional advice, and — like any language system — may occasionally be inaccurate; always verify the result on the board. When the AI tutor is unavailable on your device, the app falls back to template-based hints, without AI, with the same logical correctness. No data of yours is sent off your device to generate this content.

5. Acceptable use#

You agree to use the App lawfully and not to interfere with its operation, attempt to circumvent subscription or security mechanisms, reverse-engineer the App, or use it for any purpose that violates applicable law or the App Store's terms.

6. Intellectual property#

The App, its brand, its content, and its technology are owned by VertexHub do Brasil Ltda ("VertexHub") or licensed to it, and are protected by law. These Terms do not transfer to you any intellectual property right beyond the license granted in Section 2.

7. Warranties, liability, and support#

The App is provided "as is," to the maximum extent permitted by law, subject to the rights afforded to consumers under Brazil's Consumer Protection Code, which prevail over any limitation herein. We, not Apple, are solely responsible for the App and for providing any maintenance and support services — Apple has no obligation whatsoever to furnish support for the App. For support, contact vertexhub@vertexhub.ai.

8. Apple as third-party beneficiary#

You acknowledge that Apple and its subsidiaries are third-party beneficiaries of these Terms, and that, upon your acceptance, Apple will have the right to enforce these Terms against you as a third-party beneficiary. In the event of any third-party claim that the App or your use of it infringes intellectual property rights, we — not Apple — will be responsible for the investigation, defense, and resolution of any such claim, to the extent required by these Terms and by law.

9. Changes#

We may update these Terms to reflect changes to the App or to applicable law. The "Last updated" date indicates the version in effect; continued use of the App after material changes constitutes acceptance of the updated Terms.

10. Governing law and venue#

These Terms are governed by the laws of Brazil. The courts of the Comarca of São Paulo, SP, Brazil, have exclusive jurisdiction, without prejudice to a consumer's right to bring proceedings in the courts of their place of domicile, as provided under Brazil's Consumer Protection Code.

11. Contact#

VertexHub do Brasil Ltda — CNPJ 68.119.875/0001-40 — Avenida Engenheiro Luiz Carlos Berrini, 1748, Cidade Monções, São Paulo, SP, CEP 04571-000, Brazil. Email: vertexhub@vertexhub.ai.