Legal document

Terms of Service

Last updated: 2026-06-05

This summary is provided for transparency and is not specific legal or tax advice. Questions? Contact support@billsos.com.

Welcome to BillsOS, invoicing and billing software for Thai freelancers and small businesses, operated by Cavastir. Please read these Terms before using the Service.

1. Definitions

"Service" means the BillsOS platform including the website, API, and all features. "Cavastir" means the company operating BillsOS. "User" means the individual or legal entity registered to use the Service.

2. Nature of the Service — BillsOS is not a financial institution

BillsOS is invoicing and billing software. It is NOT a bank, payment processor, or e-money issuer and never holds, receives, transfers, or processes customer funds in any capacity.

All payments flow directly between the seller and buyer through the seller's own PromptPay account. Funds reach the User's bank account directly without passing through Cavastir. BillsOS charges no fee on PromptPay payments received. SaaS subscription billing is handled solely by Stripe.

3. User Tax Responsibilities

The User is solely responsible for the accuracy of tax documents issued through the Service, and for their own tax filing and compliance with applicable Thai tax law. BillsOS provides document-creation tools only — not tax, legal, or accounting advice.

If you are unsure about your tax obligations, please consult a licensed accountant or legal adviser.

4. Account Registration and Security

You must provide accurate, complete, and current information when registering. You are responsible for maintaining the security of your account credentials and for all activities that occur under your account.

5. Acceptable Use

You agree not to:

Use the Service for any unlawful, fraudulent, or deceptive purpose
Upload or store content that infringes third-party rights
Attempt to access another user's account or data without authorisation
Reverse-engineer, decompile, or copy any part of the Service
Transmit malware, spam, or otherwise overload the system

6. Intellectual Property

The Service, including its software, UI, design, and all content, is owned by Cavastir or its licensors and is protected by intellectual-property law. You receive only a limited, non-transferable, revocable licence to use it as permitted by these Terms.

Content you create (documents, customer data, business logos) remains your property; you grant Cavastir a limited licence solely to operate the Service for you.

7. Service "As Is" — No Warranty

The Service is provided "as is" and "as available" without warranty of any kind, express or implied, including without limitation warranties of merchantability or fitness for a particular purpose. Cavastir does not warrant that the Service will be error-free, uninterrupted, or virus-free.

8. Limitation of Liability

To the maximum extent permitted by Thai law, Cavastir will not be liable for indirect, consequential, special, or punitive damages, including loss of profits, data, or goodwill, arising from the use of or inability to use the Service. Cavastir's total aggregate liability to a User shall not exceed the amounts paid by that User to Cavastir in the preceding 12 months.

9. Suspension and Termination

Cavastir reserves the right to suspend or terminate accounts that violate these Terms or that are used in a manner harmful to other users or the system. You may terminate your account at any time from the in-app account portal.

10. Changes to these Terms

Cavastir may update these Terms from time to time. Notice will be sent to your registered email and/or displayed within the Service. Continued use after changes take effect constitutes acceptance of the revised Terms.

11. Governing Law

These Terms are governed by and construed in accordance with the laws of the Kingdom of Thailand. Any disputes will be subject to the jurisdiction of the competent Thai courts.

12. Contact

For questions about these Terms, please contact support@billsos.com.