Terms — usezn subscriptions and billing

Agreement to Terms

By accessing or using zn ("the Service"), you agree to be bound by these Terms of Service. If you do not agree to these terms, do not use the Service.

Description of Service

zn provides a prompt injection detection API for AI agents. The Service analyzes text input and returns a verdict (allow/block), confidence score, and evidence ID for audit purposes.

Subscriptions and Billing

Merchant of Record: All payments are processed by Polar.sh, our Merchant of Record. Polar handles billing, invoicing, tax collection, and payment processing on our behalf.

Plans: We offer the following subscription plans:

Contributor: $0/month - 10,000 calls, 500 Galvanize-60M neural checks (research tier; anonymized telemetry is used to improve zn)
Trial: free for 7 days - 5,000 calls, 500 Galvanize-60M neural checks
Starter: $29/month - 500,000 calls, 5,000 Galvanize-60M neural checks (annual billing available at −20%)
Growth: $99/month - 2,000,000 calls, 20,000 Galvanize-60M neural checks (annual billing available at −20%)
Enterprise: custom pilot contract - dedicated Galvanize-60M capacity, contact enterprise@usezn.com

Overage packs: When you exceed your plan, buy one-time packs: Flex $19 for 100,000 calls, Pro $49 for 500,000, Scale $99 for 1,000,000. Pack credits never expire. Metered overage at $0.0002/call ($0.20 per 1,000 calls) applies only if configured on your plan.

Retention: Evidence records are kept for 90 days with SHA-256 hashing, consistent with our Privacy Policy.

Research telemetry (Contributor): By enrolling in the free Contributor plan you grant permission to use anonymized, PII-scrubbed routing telemetry to train open zn models. Paid tiers are excluded: they run under strict Zero Data Retention and never contribute training data.

Billing Cycle: Subscriptions are billed monthly via Polar.sh. You can upgrade, downgrade, or cancel anytime via Polar self-service.

Refunds: Contact us during the 7-day trial if you have billing questions. For other refund requests, contact support.

Acceptable Use

You agree not to:

Use the Service for any illegal purpose
Attempt to circumvent rate limits or usage quotas
Reverse engineer or attempt to extract the detection algorithms
Resell or redistribute the Service without authorization
Use the Service to develop competing products

Service Level

We work to keep the API available and monitor it internally, but we do not publish a contractual uptime SLA. An SLA can be agreed in writing for enterprise contracts. The Service is provided "as is" without warranty of any kind. We do not guarantee that the Service will detect all prompt injection attempts or that it will be error-free.

Limitation of Liability

To the maximum extent permitted by law, zn shall not be liable for any indirect, incidental, special, consequential, or punitive damages, including loss of profits, data, or business opportunities, arising from your use of the Service.

Termination

We may terminate or suspend your access to the Service at any time, with or without cause, with or without notice. Upon termination, your right to use the Service will immediately cease.

Changes to Terms

We reserve the right to modify these terms at any time. We will notify you of material changes via email or through the Service. Continued use of the Service after changes constitutes acceptance of the new terms.

Contact

For questions about these terms, contact us at legal@usezn.com or reach out on X @use_zn.