Terms of Service

Effective September 3, 2026

1. Who we are and what these terms cover

These Terms of Service (the “Terms”) are an agreement between you and Powerline LLC, a limited liability company based in the United States (“Powerline”, “we”, “us”). They govern your use of:

• the website at powerline.ai, including the Inbox Preview trial pages;
• the Inbox Preview API at api.powerline.ai, including its hosted MCP endpoint, its OpenAPI and skills documentation, and any other programmatic interface we offer;
• the Powerline Inbox Preview extension for Visual Studio Code and compatible editors; and
• any other software or service we make available that links to these Terms

(together, the “Services”). By accessing or using the Services you agree to these Terms. If you do not agree, do not use the Services.

If you use the Services on behalf of a company or other organisation, you represent that you have authority to bind it, and “you” refers to both you and that organisation.

2. Eligibility

You must be at least 18 years old, or the age of majority where you live if that is higher, to use the Services. You may not use the Services if doing so is prohibited by law where you are.

3. What the Services do

Inbox Preview shows you how an HTML email renders in real email clients. When you submit an email as HTML or as a raw .eml message, we:

1. place a copy of it in a test mailbox that we control at each email provider you selected (currently Google’s Gmail, Microsoft’s Outlook.com, and Yahoo Mail, all as their web applications render them);
2. open it in that provider’s web application under the options you chose, such as viewport width, light or dark colour scheme, and whether remote images are blocked;
3. capture screenshots of the result and make them available to you through the Services; and
4. remove the message from the test mailbox.

The set of available clients and options is determined at the time of each request and can change without notice, for example while a client is offline. We currently offer the Services free of charge. We may introduce paid plans, usage tiers, or accounts in the future; if we do, we will publish the applicable terms before they take effect.

4. Access, job IDs, and credentials

No account is required today. Access is anonymous and rate limits are applied per network address (see Section 5).

Each submission creates a job identified by a long, random job ID. The job ID is the only credential protecting that job’s results: anyone who has the ID can retrieve the screenshots and metadata until the job expires. We never publish job IDs, and you are responsible for whom you share them with.

If we issue you an API key or other credential in the future, you must keep it confidential and you are responsible for all activity performed with it.

5. Rate limits and fair use

Anonymous use is currently limited to 30 submissions per hour per network address, and to the request-size limits stated in the API documentation. We may change these limits at any time; the API documentation and error responses state the limits in force.

You agree not to circumvent rate limits or other access controls, including by rotating network addresses or otherwise disguising the origin of requests; not to place unreasonable load on the Services; and not to probe, scan, or test the Services or the email providers’ systems for vulnerabilities except as we have authorised in writing.

6. Your content

You keep all rights in the emails, HTML, images, and other material you submit (“Content”). We do not claim ownership of it.

So that we can provide the Services, you grant Powerline a limited, non-exclusive, worldwide, royalty-free licence to receive, store, copy, transmit, display, and process your Content, including transmitting it to the email providers’ systems described in Section 3 and storing the resulting screenshots for the retention period in Section 8. This licence exists only to operate, secure, and improve the Services and ends when your Content and the derived results are deleted.

We do not use your Content to train machine-learning models, and we do not sell it or use it for advertising.

You represent and warrant that you have all rights needed to submit your Content and to grant this licence, and that your Content and your use of the Services comply with applicable law and with Section 7.

7. Acceptable use

You must not use the Services to submit, create, or test:

• content that is illegal, or that infringes or misappropriates anyone’s intellectual-property, privacy, or other rights;
• phishing, fraud, impersonation, or other deceptive messages, or any email designed to mislead recipients about its sender or purpose;
• malware, exploits, or content intended to interfere with any system, including the email providers’ systems and our own;
• content containing other people’s personal data that you do not have a lawful basis to share with us, or sensitive data such as health information, financial account details, government identifiers, or authentication credentials. Use placeholder data in test emails.

You also must not attempt to gain access to the test mailboxes or provider accounts we use, interfere with other users’ use of the Services, resell the Services without our written permission, or use the Services to build a directly competing product by systematically extracting its outputs.

The Services do not send email to anyone. They place a copy of your message in mailboxes we control solely to render it.

8. Data handling and retention

What we process

• Your Content, as submitted, together with the render options you chose.
• Results: screenshots, image dimensions, timings, and other render metadata.
• Request metadata: network address, user agent, timestamps, request identifiers, and error details, recorded in operational logs for security, abuse prevention, and debugging.
• Website analytics: powerline.ai uses Google Analytics and PostHog to measure site usage. The API and the VS Code extension do not include analytics or telemetry.

How long we keep it

• Jobs, including your Content and the results, are available for 24 hours after submission. After that the job expires and its files are deleted from our servers within about an hour.
• The copy placed in a provider’s test mailbox is removed once rendering completes. Depending on the provider it is deleted outright or moved to that mailbox’s trash, which the provider purges on its own schedule, typically within 30 days.
• Operational logs are kept for a limited period and then discarded.

Who else handles your data

To provide the Services we rely on third parties that process data on our behalf: the email providers named in Section 3, which receive your Content in order to render it; Cloudflare, which hosts the website and carries network traffic to the API; DigitalOcean, which hosts the API servers; and Google Analytics for website usage measurement. These providers may process data in countries other than your own. We do not share your Content with anyone else except where required by law.

Your local machine

The VS Code extension stores your render history in your workspace settings and caches downloaded screenshots in the editor’s storage directory for the extension. Both live only on your machine and can be deleted at any time.

9. Third-party services and trademarks

Gmail and Google are trademarks of Google LLC. Outlook and Microsoft are trademarks of Microsoft Corporation. Yahoo is a trademark of Yahoo Inc. Powerline is not affiliated with, endorsed by, or sponsored by any of these companies. Their applications change without notice, and a screenshot reflects only how a provider rendered your Content at the moment of capture.

10. Intellectual property

The Services, including their software, documentation, design, and the powerline.ai website, are owned by Powerline or its licensors and are protected by intellectual-property law. Subject to these Terms, we grant you a limited, non-exclusive, non-transferable, revocable right to use the Services for their intended purpose. Components we release under an open-source licence, such as the VS Code extension, which is available under the MIT licence, are governed by that licence for the component itself.

If you send us feedback or suggestions, you grant us a perpetual, irrevocable, royalty-free licence to use them without obligation to you.

11. Automated and agent use

The Services are designed to be used by software, including AI agents acting through the API, the MCP endpoint, or the VS Code extension. Automated use is permitted subject to these Terms. You are responsible for every request made by software or agents operating on your behalf or with your credentials, and rate limits apply regardless of how a request is made.

12. Availability and changes

The Services are provided without any uptime or service-level commitment. We may modify, suspend, or discontinue any part of the Services at any time, with or without notice, including because an email provider changes or blocks the access we rely on. We will try to give reasonable notice of material changes where practical.

13. No warranty

THE SERVICES AND ALL RESULTS ARE PROVIDED “AS IS” AND “AS AVAILABLE”, WITH ALL FAULTS, AND WITHOUT WARRANTY OF ANY KIND. TO THE MAXIMUM EXTENT PERMITTED BY LAW, POWERLINE DISCLAIMS ALL WARRANTIES, WHETHER EXPRESS, IMPLIED, OR STATUTORY, INCLUDING WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, NON-INFRINGEMENT, ACCURACY, AND ANY WARRANTY ARISING FROM COURSE OF DEALING OR USAGE OF TRADE. WITHOUT LIMITING THE FOREGOING, WE DO NOT WARRANT THAT A SCREENSHOT MATCHES WHAT ANY PARTICULAR RECIPIENT WILL SEE; THAT THE SERVICES WILL BE AVAILABLE, UNINTERRUPTED, SECURE, OR ERROR-FREE; THAT ANY EMAIL PROVIDER WILL CONTINUE TO BE AVAILABLE; OR THAT CONTENT OR RESULTS WILL BE RETAINED OR DELETED ON ANY PARTICULAR SCHEDULE. THE SERVICES ARE NOT A DELIVERABILITY, SPAM-FILTER, ACCESSIBILITY, OR LEGAL-COMPLIANCE TEST, AND RESULTS ARE NOT ADVICE.

The descriptions in these Terms of how the Services operate, including the retention periods in Section 8, are provided for transparency and describe our current practice. They are not warranties, guarantees, or service commitments, and we may change them at any time. No advice or information, whether oral or written, obtained from Powerline or through the Services creates any warranty. Some jurisdictions do not allow the exclusion of certain warranties, so some of the above may not apply to you; in that case our warranties are limited to the minimum the law requires.

14. Limitation of liability

TO THE MAXIMUM EXTENT PERMITTED BY LAW, POWERLINE WILL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES, OR FOR ANY LOSS OF PROFITS, REVENUE, DATA, OR GOODWILL, ARISING OUT OF OR RELATED TO THE SERVICES OR THESE TERMS, HOWEVER CAUSED AND UNDER ANY THEORY OF LIABILITY, EVEN IF WE HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. OUR TOTAL LIABILITY FOR ALL CLAIMS ARISING OUT OF OR RELATED TO THE SERVICES OR THESE TERMS WILL NOT EXCEED THE GREATER OF THE AMOUNTS YOU PAID US FOR THE SERVICES IN THE TWELVE MONTHS BEFORE THE CLAIM AROSE AND ONE HUNDRED US DOLLARS (USD 100). These limitations do not apply to liability that cannot be limited by law.

15. Indemnification

You will defend, indemnify, and hold harmless Powerline and its officers, directors, employees, and agents from any claims, damages, liabilities, and expenses, including reasonable legal fees, arising out of or related to your Content, your use of the Services, or your breach of these Terms.

16. Suspension and termination

We may suspend or block your access to the Services, including by network address, immediately and without notice if we reasonably believe you have breached these Terms, are abusing the Services, or are creating risk or legal exposure for us or the email providers we rely on. You may stop using the Services at any time. Sections 6 (as to the licence for Content still being processed), 8, 9, 10, and 13 through 19 survive any termination.

17. Changes to these Terms

We may update these Terms from time to time. When we do, we will post the revised Terms at powerline.ai/terms with a new effective date. For material changes we will also provide notice through the Services or the website where practical. Your continued use of the Services after the effective date means you accept the revised Terms.

18. Governing law and disputes

These Terms are governed by the federal laws of the United States and the laws of the U.S. state in which Powerline LLC is organised (the “Home State”), without regard to conflict-of-laws rules. Any dispute arising out of or relating to these Terms or the Services will be resolved exclusively in the state or federal courts located in the Home State, and you consent to their personal jurisdiction and venue. The United Nations Convention on Contracts for the International Sale of Goods does not apply. Before filing a claim, you agree to contact us at [email protected] and to attempt in good faith to resolve the dispute informally for at least 30 days.

19. General

• Entire agreement. These Terms, together with any terms we publish for paid plans or specific features, are the entire agreement between you and Powerline about the Services and supersede any prior agreements.
• Severability. If any provision is found unenforceable, it will be enforced to the maximum extent permitted and the remaining provisions will stay in effect.
• No waiver. Our failure to enforce a provision is not a waiver of our right to do so later.
• Assignment. You may not assign these Terms without our written consent. We may assign them in connection with a merger, acquisition, reorganisation, or sale of assets.
• Export and sanctions. You will comply with applicable export-control and sanctions laws, and you represent that you are not located in, or a resident of, a country or territory subject to comprehensive sanctions, and are not on any restricted-party list.
• No third-party beneficiaries. These Terms create no rights for anyone other than you and Powerline.

20. Contact

Questions about these Terms and reports of abuse or infringing content can be sent to [email protected].