Last updated: June 2026.
Double Check ("the Software") is a browser extension that assists users in verifying values they enter into web forms. It is an assistive tool: it helps you perform verification; it does not perform verification for you.
Use of the Software is also governed by our Privacy Policy.
You must be at least 18 years old, or the age of majority in your jurisdiction, to purchase a subscription or license.
Subject to these Terms, Possibility Outpost Inc. grants you a limited, non-exclusive, non-transferable, revocable license to install and use the Software for your personal or internal business purposes.
THE SOFTWARE IS PROVIDED "AS IS" AND "AS AVAILABLE", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO WARRANTIES OF ACCURACY, MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
Double Check does not and cannot guarantee that any value is correct. Format and checksum validation can confirm that a value is internally consistent, not that it is the right value. A verification "match" means your two readings of your source agreed — it does not mean the source itself was correct, current, or authentic.
What the Software does: it detects disagreement between two entries of a value; it detects formatting and checksum inconsistencies; and it records that you attested to a comparison.
What the Software does not do: it does not verify that a value is true, that an account exists or is owned by the party you intend, that a source document is authentic or current, that a transaction is authorized, or that a destination is correct.
The Software is a decision-support tool only and is not a substitute for independent verification procedures. Users must independently verify all information before submitting, transmitting, or relying upon it.
You remain solely responsible for every value you submit, including values verified with the Software. The attestation you confirm in the product states this explicitly, and the verification log records that you attested — not that the value was objectively correct.
The verification log is stored locally in your browser's extension storage, on your device only. It can be lost — for example if you uninstall the extension, clear browser data, or lose the device — and it is subject to the retention period you configure. Verification logs are provided for convenience only. We do not guarantee their availability, retention, accuracy, or suitability as evidence for any legal, regulatory, accounting, or compliance purpose.
TO THE MAXIMUM EXTENT PERMITTED BY LAW, IN NO EVENT SHALL THE DEVELOPER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR EXEMPLARY DAMAGES — INCLUDING WITHOUT LIMITATION FINANCIAL LOSS ARISING FROM MISDIRECTED PAYMENTS, TRANSFERS, OR TRANSACTIONS — ARISING FROM OR RELATED TO YOUR USE OF THE SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
TO THE MAXIMUM EXTENT PERMITTED BY LAW, THE TOTAL AGGREGATE LIABILITY OF POSSIBILITY OUTPOST INC. ARISING OUT OF OR RELATED TO THE SOFTWARE SHALL NOT EXCEED THE GREATER OF (A) THE AMOUNT PAID BY YOU FOR THE SOFTWARE IN THE TWELVE MONTHS PRECEDING THE CLAIM OR (B) USD $50.
You agree to indemnify and hold harmless Possibility Outpost Inc., its officers, directors, employees, and contractors from claims, losses, liabilities, and expenses (including reasonable attorneys' fees) arising out of your use of the Software or your violation of these Terms.
These Terms are governed by the laws of the State of California, without regard to its conflict-of-laws principles.
Before filing any claim, you agree to contact us at tmh@possibility.com and attempt in good faith to resolve the dispute informally for thirty days. Any dispute not resolved informally shall be resolved by binding arbitration administered by the American Arbitration Association under its Consumer Arbitration Rules, conducted on an individual basis. Either party may instead bring an individual claim in small-claims court. Nothing in this section prevents either party from seeking injunctive or other equitable relief to protect intellectual property rights.
YOU AND POSSIBILITY OUTPOST INC. EACH WAIVE THE RIGHT TO A JURY TRIAL AND THE RIGHT TO PARTICIPATE IN A CLASS ACTION. Disputes may be brought only in an individual capacity, and not as a plaintiff or class member in any purported class or representative proceeding.
Any dispute not subject to arbitration shall be resolved exclusively in the state or federal courts located in Santa Clara County, California.
Paid plans are billed through ExtensionPay/Stripe. Subscriptions renew automatically until cancelled; you can cancel any time via the manage page in the extension, effective at the end of the paid period. Core double-entry verification continues to work without an active subscription.
A "lifetime" license is a one-time purchase covering the lifetime of this product — the Double Check browser extension, including its updates — for as long as it is offered. It does not extend to separate products (for example, future native desktop applications), which may be licensed and priced independently. A lifetime license does not guarantee that the Software will be maintained, updated, or made available indefinitely; if the Software is discontinued, the lifetime license terminates when the Software is no longer offered.
We may suspend or terminate access at any time for violation of these Terms or misuse of the Software, including fraud, payment chargebacks, or attempts to bypass licensing.
You may not attempt to circumvent, disable, interfere with, or reverse engineer the Software's privacy, security, licensing, or access-control mechanisms. You may not use the Software to violate law or third-party rights, may not resell it, and may not use it in violation of applicable export control or sanctions laws.
The Software operates on third-party websites and services that are not controlled by Possibility Outpost Inc. We are not responsible for changes, errors, interruptions, compatibility issues, or security issues arising from third-party websites, browsers, operating systems, or services. We are not responsible for interruptions or failures caused by events beyond our reasonable control.
We may update these terms; material changes will be noted in the extension's release notes. Continued use after a change constitutes acceptance.
Possibility Outpost Inc · tmh@possibility.com