End User License Agreement

SpamGate — Version 1.0 · Effective 22 July 2026

This End User License Agreement ("Agreement") is between Heuristicworks LLC, a Delaware limited liability company ("Licensor", "we", "us") and the individual installing or using the SpamGate Chrome extension ("Licensee", "you"). By installing the Extension, clicking "Add to Chrome", or using the Extension in any way, you accept this Agreement in full.

1. Definitions

"Extension" means the SpamGate Google Chrome browser extension, including all popup interfaces, background service workers, content scripts, updates, and documentation.

"Free Tier" means the no-charge tier of the Extension that permits creation of up to 10 sender-address filter rules. Domain-based rules are not available on the Free Tier.

"Pro Tier" means the paid subscription tier, billed at $2.00 USD per month or $15.00 USD per year, that permits unlimited sender-address and domain filter rules.

"Gmail API" means Google's Gmail API, which the Extension uses to create filter rules and apply label changes in your Gmail account.

"Filter Rule" means a Gmail filter created in your Google account by the Extension, specifying that messages from a given sender address or domain should be moved to Trash, Spam, or archived.

"Subscription" means a paid Pro Tier subscription processed by Stripe, Inc. on behalf of Licensor.

"Backend Service" means Licensor's server-side service, operated on Cloudflare Workers, that validates subscription status and processes Stripe checkout sessions.

2. Grant of Licence

Subject to your compliance with this Agreement, Licensor grants you a limited, non-exclusive, non-transferable, non-sublicensable, revocable licence to install and use one copy of the Extension on Chrome-compatible browsers under your control, solely for the purpose of managing your own Gmail inbox.

This licence does not include the right to:

(a) Install the Extension on behalf of other users unless you are an IT administrator managing corporate devices under a written organisational policy permitting such use;

(b) Use the Extension to manage Gmail accounts that are not your own, without explicit written permission from Licensor;

3. Free Tier and Pro Tier

3.1 Free Tier

The Free Tier is available to all users at no charge, subject to a limit of 10 sender-address filter rules total across all filter groups (Trash, Spam, and Junk combined). Domain-based filter rules are not available on the Free Tier. Licensor reserves the right to modify Free Tier limits on 30 days' notice.

3.2 Pro Tier

The Pro Tier removes all rule limits and enables domain-based filter rules. Pro Tier access requires an active Subscription.

3.3 Subscription Billing

(a) Subscriptions are billed by Stripe, Inc. Monthly subscriptions are billed in advance each month. Annual subscriptions are billed in advance each year.

(b) Subscriptions renew automatically unless cancelled before the renewal date.

(c) You may cancel at any time via the Extension's popup interface or by contacting support@heuristicworks.com. Cancellation takes effect at the end of the current paid period; access reverts to the Free Tier at that time.

(d) Subscription fees are non-refundable except: (i) where required by applicable consumer protection law; or (ii) where Licensor materially fails to provide Pro Tier features for more than 72 consecutive hours due to causes within Licensor's control and you request a refund within 14 days.

(e) Licensor may change Subscription prices on 30 days' written notice. Changes take effect at your next renewal.

4. Licence Restrictions

You must not, and must not permit any third party to:

(a) Reverse engineer, decompile, disassemble, or attempt to derive source code from the Extension, except to the extent expressly permitted by applicable law and then only after prior written notice to Licensor;

(b) Modify, adapt, translate, or create derivative works based on the Extension;

(d) Use the Extension to access, read, modify, or delete email content or accounts you do not own or are not authorised to manage;

(e) Use automated scripts, bots, or other means to circumvent the Free Tier rule limit;

(f) Create multiple Google accounts to obtain additional Free Tier capacity;

(g) Share, resell, or sublicense Pro Tier access to third parties;

(h) Use the Extension in any way that violates Google's Terms of Service, Gmail's Terms of Service, or the Gmail API terms;

(i) Attempt to access the Backend Service API by means other than the Extension's own API calls;

(j) Create Filter Rules designed to harm, harass, stalk, or cause economic damage to any person, or to destroy evidence of criminal activity.

5. Intellectual Property

5.1 Licensor Ownership

The Extension, including its source code, design, icons, and documentation, is and remains the exclusive property of Licensor and its licensors. This Agreement does not transfer any ownership interest in the Extension to you.

5.2 Google Trademarks

Gmail, Google, and the Google logo are trademarks of Google LLC. Heuristicworks is not affiliated with or endorsed by Google. Use of Google's marks in the Extension's name and description is solely for the purpose of describing compatibility with Gmail.

5.3 Feedback

If you provide suggestions, ideas, or feedback about the Extension, Licensor may use them without restriction and without compensation to you.

6. Data and Privacy

6.1 Gmail API Access

The Extension accesses your Gmail account through the Gmail API using the OAuth 2.0 scopes described in the Terms of Use. Licensor complies with the Google API Services User Data Policy.

6.2 Local Storage

The Extension stores data locally in your browser (chrome.storage.local), including your OAuth token, Gmail address, filter group configuration, and plan cache. This data is not synced across devices.

6.3 Data Transmitted to Licensor

Your Gmail email address is transmitted to the Backend Service for subscription status verification and Stripe checkout initiation. No Gmail message content is transmitted to Licensor's servers. Your email address and subscription status are stored in Licensor's Cloudflare D1 database.

6.4 Privacy Policy

Licensor's full Privacy Policy is available at trustcenter.heuristicworks.com/enterprise/legal/privacy-policy. By using the Extension, you consent to the data practices described therein.

6.5 Google API Services User Data Policy

Licensor's use of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements. Gmail API data accessed through the Extension is used solely to create filter rules and apply label changes as directed by you. It is not shared with third parties for advertising, data mining, or any purpose unrelated to the Extension's inbox management functionality.

7. Third-Party Services

7.1 Google / Gmail API

The Extension depends on Google's Gmail API. Licensor does not control Google's API availability, quotas, or changes to Gmail's web interface. Licensor will use reasonable efforts to maintain compatibility but is not liable for loss of functionality caused by Google's actions.

7.2 Stripe

Payment processing for the Pro Tier is handled by Stripe, Inc. Your payment card details are provided directly to Stripe and are not stored by Licensor.

7.3 Cloudflare Workers

The Backend Service is hosted on Cloudflare's Workers platform. Licensor is not liable for service outages caused by Cloudflare's infrastructure.

8. Warranties and Disclaimers

8.1 Licensor Warranties

Licensor warrants that: (a) it has the right to grant the licences in this Agreement; and (b) the Extension does not, to Licensor's knowledge as of the effective date, infringe the intellectual property rights of any third party.

8.2 Disclaimer of Warranties

TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, THE EXTENSION IS PROVIDED "AS IS" AND "AS AVAILABLE". LICENSOR EXPRESSLY DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND NON-INFRINGEMENT. LICENSOR DOES NOT WARRANT THAT THE EXTENSION WILL BE UNINTERRUPTED, ERROR-FREE, OR COMPATIBLE WITH FUTURE VERSIONS OF CHROME OR GMAIL, OR THAT DEFECTS WILL BE CORRECTED.

FILTER RULES CREATED BY THE EXTENSION CAN PERMANENTLY MOVE, ARCHIVE, OR TRASH EMAIL MESSAGES. LICENSOR MAKES NO WARRANTY THAT FILTER RULES WILL OPERATE AS EXPECTED ON ALL MESSAGES. YOU ARE SOLELY RESPONSIBLE FOR REVIEWING AND VALIDATING THE FILTER RULES YOU CREATE.

9. Limitation of Liability

9.1 Exclusion of Consequential Damages

TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, IN NO EVENT SHALL LICENSOR BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION LOSS OF EMAIL MESSAGES, LOSS OF DATA, LOSS OF BUSINESS OPPORTUNITY, OR BUSINESS INTERRUPTION, ARISING OUT OF OR RELATED TO THIS AGREEMENT OR THE EXTENSION, EVEN IF LICENSOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

9.2 Aggregate Cap

TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, LICENSOR'S AGGREGATE LIABILITY TO YOU FOR ALL CLAIMS ARISING OUT OF OR RELATED TO THIS AGREEMENT SHALL NOT EXCEED THE GREATER OF: (A) THE TOTAL SUBSCRIPTION FEES PAID BY YOU TO LICENSOR IN THE TWELVE MONTHS PRECEDING THE CLAIM; OR (B) TEN US DOLLARS ($10).

9.3 Essential Basis

The parties acknowledge that the limitations in this Section reflect a reasonable allocation of risk and form an essential basis of the bargain between them.

9.4 Exceptions

Nothing in this Agreement limits liability for: (a) death or personal injury caused by negligence; (b) fraud or fraudulent misrepresentation; (c) wilful misconduct; or (d) any liability that cannot be excluded or limited under applicable law.

10. Indemnification

You agree to defend, indemnify, and hold harmless Licensor and its affiliates, officers, directors, employees, and agents from and against any third-party claims, liabilities, damages, costs, and expenses (including reasonable legal fees) arising out of or related to: (a) your use of the Extension in violation of this Agreement; (b) your violation of Google's Terms of Service or the Gmail API terms; (c) Filter Rules you create that result in unintended loss of or damage to email; or (d) your violation of any applicable law.

11. Term and Termination

11.1 Term

This Agreement is effective from the date of Extension installation and continues until terminated.

11.2 Termination by You

You may terminate this Agreement at any time by uninstalling the Extension. Uninstalling removes the Extension from your browser but does not automatically delete Filter Rules from your Gmail account or your data from the Backend Service. To request deletion of your backend data, contact support@heuristicworks.com.

11.3 Termination by Licensor

Licensor may terminate this Agreement and suspend your access immediately, without notice or refund, upon: (a) your breach of this Agreement; (b) fraudulent use of the Extension or payment fraud; (c) your violation of Google's Terms of Service through use of the Extension; or (d) removal of the Extension from the Chrome Web Store.

11.4 Effect of Termination

On termination: (a) the licence granted in Section 2 immediately ceases; (b) Filter Rules previously created in your Gmail account remain in place and are not automatically deleted; (c) your Subscription (if active) is cancelled; (d) Sections 5, 8, 9, 10, 11.4, 12, and 13 survive termination.

12. Export Controls

You agree to comply with all applicable export control, sanctions, and trade compliance laws. You represent that you are not located in, organised under the laws of, or controlled by a government of a jurisdiction subject to comprehensive US or EU trade sanctions, and that you are not on any applicable denied-persons list.

13. General Provisions

13.1 Governing Law

This Agreement is governed by the laws of the State of Delaware, USA, without regard to conflict of law principles.

13.2 Dispute Resolution

Any dispute arising out of or relating to this Agreement shall first be subject to good-faith negotiation for 30 days. If unresolved, disputes shall be resolved by binding arbitration administered by the AAA under its Commercial Arbitration Rules, in Wilmington, Delaware. Either party may seek injunctive relief in any court of competent jurisdiction.

13.3 Entire Agreement

This Agreement, together with the Terms of Use, Privacy Policy, and Acceptable Use Policy, constitutes the entire agreement between the parties regarding the Extension and supersedes all prior agreements and understandings.

13.4 Amendments

Licensor may update this Agreement by publishing a revised version at trustcenter.heuristicworks.com/products/spamgate/legal/eula and notifying you by email at least 30 days before the revised version takes effect. Continued use of the Extension constitutes acceptance.

13.5 Waiver and Severability

Failure to enforce any provision does not constitute a waiver. If any provision is found invalid, it will be modified minimally to become enforceable, and the remaining provisions continue in effect.

13.6 Assignment

You may not assign this Agreement without Licensor's prior written consent. Licensor may assign this Agreement to an affiliate or in connection with a merger, acquisition, or sale of substantially all assets.

13.7 Contact

Support: support@heuristicworks.com
Legal: legal@heuristicworks.com

Heuristicworks LLC · Spring City, PA, USA