Terms & Conditions

Last updated: July 6, 2026

1. Acceptance of Terms

By creating an account or submitting a job through ZKSF (the “Service”), you agree to these Terms.
If you use the Service on behalf of an organization, you represent that you have authority to bind it.
We may update these Terms; material changes will be dated at the top of this page and notified via the email on your account.

ZKSF provides cloud-based classical simulation of quantum circuits (on CPU and GPU) and access to real quantum processing units (QPUs) on third-party quantum hardware, all through the same service and API.
Simulation methods include exact statevector, stabilizer, and approximate tensor-network techniques. Approximate methods carry method-dependent accuracy limits, reported with each result.
The Service may reject circuits it cannot execute reliably; rejection diagnostics are provided on a best-effort basis.

Exact simulations are exact up to floating-point precision and sampling (shot) noise.
Approximate simulations (e.g., MPS/tensor networks) return estimates. Accompanying error indicators (such as convergence deviation) are evidence-based estimates, not mathematical guarantees, unless explicitly labeled as certified bounds.
You are responsible for validating results before relying on them in research, publication, or commercial decisions.
Results from third-party quantum hardware reflect that hardware’s physical noise and calibration; we do not control and cannot warrant hardware fidelity.

ZCC-v0.1 (the ZKSF Convergence Certificate, for simulated results) and ZHF-v0.1 (the ZKSF Hardware Fidelity certificate, for real quantum-hardware results) are our own in-house protocols, developed, versioned, and maintained by ZKSF.
The specification and methodology behind both protocols are published openly (see our methodology write-up), and fair use of the protocols, including citing, independently reproducing, or referencing certificate methodology in your own work, is expressly permitted.
A certificate reflects the method, parameters, and accuracy or fidelity statement for the specific job it was generated from, as described in Section 3 above; it is not a warranty of correctness beyond what that statement itself claims.
Questions about certification, verification, or the protocols themselves: info@zksf.org.

Quantum hardware access (e.g., Rigetti devices) is provided via third-party platforms and is subject to those providers’ terms and availability windows.
Hardware pricing is passed through at provider cost as published on our pricing page; provider price changes take effect when the provider applies them.
ZKSF is not affiliated with, endorsed by, or sponsored by any hardware vendor or cloud platform referenced by the Service.

You are responsible for safeguarding API tokens; activity under your token is attributed to your account.
You agree not to: attempt to breach or overload the Service; use it to process unlawful content; resell access without written agreement; or attempt to extract other users’ data or circuits.
Reverse engineering of the Service is prohibited except where such restriction is void by law. Benchmarking and publishing results about the Service are expressly permitted; we encourage it.

Usage is billed per job based on compute time and resources, with rates shown on the pricing page and a pre-run estimate available for every job.
Pre-run estimates are good-faith predictions, not quotes; actual billed time may differ. Estimates err conservative by design.
Disputed charges must be raised within 30 days of the invoice.
Payments are processed by Stripe; card data is handled entirely by Stripe under PCI DSS and never touches our servers.

All charges are final and non-refundable. Every job you run consumes real compute (and, for QPU jobs, real quantum-hardware invoices) the moment it executes, so the cost to us is incurred whether or not the result is what you hoped for.
In exchange, we keep pricing deliberately low so that labs, students, and independent researchers can afford the Service, and every job shows a conservative cost estimate before you commit to running it.
If we billed you for a job that failed because of a fault in the Service itself (not a rejected or user-error circuit), contact us within 30 days and we will credit it. Rejections and pre-run estimates are always free.

You retain all rights to circuits you submit and results you receive. We claim no ownership of your science.
We may retain job metadata (sizes, timings, methods, resource use) to operate, debug, and improve routing and estimation. Circuit contents are not used to train public models or shared with third parties except as required to execute your job (e.g., transmitting to a QPU provider you selected).

The Service is provided without an uptime guarantee unless covered by a separate written SLA.
Cold-start latency, queue times, and third-party hardware windows vary and are not warranted.
We may modify or discontinue features with reasonable notice where practical.

THE SERVICE IS PROVIDED “AS IS” AND “AS AVAILABLE” WITHOUT WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
TO THE MAXIMUM EXTENT PERMITTED BY LAW, OUR AGGREGATE LIABILITY ARISING FROM THE SERVICE SHALL NOT EXCEED THE AMOUNTS YOU PAID US IN THE THREE (3) MONTHS PRECEDING THE CLAIM.
WE ARE NOT LIABLE FOR INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR EXEMPLARY DAMAGES, INCLUDING LOST PROFITS, LOST DATA, OR RESEARCH DELAYS.

You agree to comply with applicable export-control and sanctions laws in your use of the Service, including restrictions on access from embargoed jurisdictions.
Quantum-hardware access may be subject to additional provider-level restrictions beyond our control.

You may close your account at any time.
We may suspend accounts for breach of these Terms, non-payment, or activity that endangers the Service or other users, with notice where practicable.