Terms of Service

Last updated: June 20, 2026

These Terms of Service ("Terms") govern your access to and use of SQLVerify (the "Service"), operated by Dat Nguyen, an individual based in Hanoi, Vietnam ("we", "us", "our"). By creating an account or using the Service, you agree to these Terms. If you do not agree, do not use the Service.

1. What SQLVerify is

SQLVerify is a formal verification tool that uses SMT (Z3) solving to check whether two SQL queries are semantically equivalent given a database schema, and to generate a counterexample database when they are not. It is a decision-support tool intended to help engineers review SQL before it ships — it is not a substitute for your own testing, code review, or judgment.

2. Eligibility and accounts

You must be at least 18 years old, or the age of legal majority in your jurisdiction, to use the Service. You are responsible for maintaining the confidentiality of your account credentials and any API keys you generate, and for all activity that occurs under your account. Notify us promptly at [email protected] if you suspect unauthorized use.

3. Plans, billing, and free tier limits

The Service offers a free tier (subject to a monthly verification-run limit, currently 100 runs per calendar month) and paid subscription plans (Individual and Team). Paid subscriptions are billed in advance on a recurring basis and processed by Lemon Squeezy, our payment processor and Merchant of Record. We do not collect or store your payment card details.

You may cancel a paid subscription at any time through the billing portal; cancellation takes effect at the end of the current billing period. Except where required by law or Lemon Squeezy's own refund policy, payments are non-refundable. We may change pricing for future billing periods with reasonable notice.

4. Your content

"Your Content" means the SQL schemas, queries, and any other data you submit to the Service. You retain ownership of Your Content. You grant us a limited license to process, store, and transmit Your Content solely to operate and improve the Service — including, when you explicitly request an explanation, sending the relevant query and counterexample data to a third-party AI provider as described in our Privacy Policy.

You are responsible for ensuring you have the right to submit Your Content, and for not submitting data you are not authorized to share (for example, schemas or queries containing real customer personal data you don't have rights to process through a third party).

5. Acceptable use

You agree not to:

  • Use the Service for any unlawful purpose, or to submit malicious, infringing, or abusive content;
  • Attempt to bypass rate limits, free-tier quotas, or authentication via multiple accounts or other circumvention;
  • Reverse-engineer, decompile, or attempt to extract the underlying verification logic or models of the Service, beyond what is permitted by the open-source license governing the underlying engine, where applicable;
  • Interfere with or disrupt the integrity or performance of the Service or its infrastructure;
  • Resell or sublicense access to the Service without our written agreement.

6. Important limitations of the verification engine

The Service's equivalence checking is sound only within the supported SQL subset and the configured verification bound described in our documentation. Queries or constructs outside that subset are rejected rather than silently ignored, but the supported subset itself has known limitations (for example, certain joins, window functions, and subqueries are not yet supported). An "equivalent" verdict is a strong signal, not an absolute guarantee for every possible database state — you remain responsible for your own testing and validation before deploying SQL changes to production.

7. Disclaimer of warranties

THE SERVICE IS PROVIDED "AS IS" AND "AS AVAILABLE," WITHOUT WARRANTIES OF ANY KIND, WHETHER EXPRESS OR IMPLIED, INCLUDING WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. WE DO NOT WARRANT THAT THE SERVICE WILL BE UNINTERRUPTED, ERROR-FREE, OR THAT VERIFICATION RESULTS WILL CATCH EVERY POSSIBLE DEFECT IN YOUR SQL.

8. Limitation of liability

TO THE MAXIMUM EXTENT PERMITTED BY LAW, WE WILL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES, OR ANY LOSS OF DATA, REVENUE, OR PROFITS, ARISING FROM YOUR USE OF THE SERVICE. OUR TOTAL LIABILITY FOR ANY CLAIM ARISING OUT OF THESE TERMS OR THE SERVICE WILL NOT EXCEED THE GREATER OF (A) THE AMOUNT YOU PAID US IN THE 12 MONTHS PRECEDING THE CLAIM, OR (B) USD 100.

9. Indemnification

You agree to indemnify and hold us harmless from any claims, damages, or expenses (including reasonable legal fees) arising from your breach of these Terms, your misuse of the Service, or Your Content.

10. Termination

We may suspend or terminate your access to the Service if you violate these Terms, or for any other reason with reasonable notice where practicable. You may stop using the Service at any time. Sections that by their nature should survive termination (including Sections 7, 8, and 9) will survive.

11. Changes to these Terms

We may update these Terms from time to time. We will update the "Last updated" date above when we do. Continued use of the Service after changes take effect constitutes acceptance of the revised Terms.

12. Governing law

These Terms are governed by the laws of Vietnam, without regard to conflict-of-law principles. Any dispute arising out of these Terms or the Service will be subject to the exclusive jurisdiction of the competent courts of Vietnam.

13. Contact

Questions about these Terms can be sent to [email protected].