Terms of Service — Sigma9 Browser Extension

Last updated: July 9, 2026

These Terms of Service (the "Terms") govern your access to and use of Sigma9 (the "Extension", "we", "us"), a browser extension that provides a simple, self-custodial, gasless USDC wallet. By installing, accessing, or using the Extension, you agree to be bound by these Terms. If you do not agree, do not install or use the Extension.

Sigma9 is an independent project developed and maintained by an individual. There is currently no associated legal entity or company. References to "we," "us," or "the developer" in these Terms mean that individual developer.

1. Self-Custody — You Alone Control Your Wallet

The Extension is non-custodial, self-custody software. Your seed phrase and private keys are generated and stored exclusively on your own device. We do not create, hold, transmit, back up, or have any access whatsoever to your seed phrase, private keys, or funds.

Because of this:

• You alone are responsible for generating, safeguarding, and backing up your seed phrase.
• We cannot recover your wallet, reset your password, reverse a transaction, or restore lost funds under any circumstances.
• We have no ability to freeze, seize, block, or access your assets, even if requested by you or by a third party (including law enforcement) — we simply do not hold the keys.
• Loss of your seed phrase or password, without a backup, means permanent and irreversible loss of access to your funds.

If you understand and accept nothing else in these Terms, understand this section.

2. Eligibility and Acceptable Use

You represent that you are of legal age to manage your own digital assets in your jurisdiction and that your use of the Extension is lawful where you are located.

You agree not to use the Extension:

• For any unlawful purpose, including money laundering, sanctions evasion, fraud, or financing of illegal activity.
• To interact with smart contracts or counterparties you know or suspect to be malicious, fraudulent, or unlawful.
• In any way that attempts to interfere with, disrupt, or circumvent the security of the Extension or the third-party infrastructure it relies on.

You are solely responsible for ensuring your use of the Extension complies with the laws applicable to you.

3. Experimental, Early-Stage Software

The Extension is currently in an early stage of development and should be considered experimental. Both mainnet (real funds, real value) and testnet (test funds, no real value) networks are fully functional, and mainnet is the default network on a fresh install — but "fully functional" does not mean "finished" or "audited." Features are actively being built, changed, and fixed. Specifically:

• Functionality may change, break, be removed, or behave unexpectedly without notice.
• Supported chains, tokens, and routes may be added, removed, or reconfigured as the project evolves. As of this writing, v1 supports USDC only, on Arbitrum, Base, and Solana (plus test networks for the same chains, and Arc Testnet); support for additional tokens or networks may or may not ever be added.
• The Extension has not undergone a formal, independent security audit.

You should not rely on the Extension for any purpose where failure, downtime, or a breaking change would be unacceptable. Because you are transacting with real assets on mainnet by default, you are strongly encouraged to start with small amounts and verify the Extension's behavior meets your needs before relying on it for anything larger — the same caution described in Sections 6 and 7 below applies in full on mainnet, not only on testnet.

4. No Financial, Legal, or Tax Advice

Nothing provided through the Extension, its interface, or any associated documentation constitutes financial, investment, legal, or tax advice. The Extension is a tool for constructing and sending transactions — it does not recommend, endorse, or evaluate any transaction, token, or counterparty.

No fiduciary relationship, agency, partnership, or joint venture is created between you and the developer by your use of the Extension. You are solely responsible for determining the suitability of any transaction, and for any tax reporting or other regulatory obligations arising from your use of the Extension in your jurisdiction.

5. Third-Party Services

To provide gasless and cross-chain functionality, the Extension communicates with third-party infrastructure that is outside our control and, in several cases, configurable by you:

• Circle — the CCTP v2 / Iris attestation service for cross-chain USDC transfers, and the Circle Paymaster used to sponsor gas in USDC.
• A relayer service (Kora) — sponsors fees for gasless operations on Solana. The relayer endpoint is user-configurable; you may point the Extension at a different or self-hosted compatible relayer.
• RPC node providers — used to read blockchain state and broadcast transactions. Default public endpoints are used, and you may configure your own custom RPC URLs.

These providers operate under their own terms of service and privacy policies, which you should review independently. We do not control, and are not responsible for, their availability, correctness, security, pricing, or continued existence. If a provider is unavailable, changes its behavior, discontinues service, or is compromised, the Extension's functionality may be degraded or unusable, and we bear no liability for that outcome (see Section 7).

6. "As Is" — No Warranty

THE EXTENSION IS PROVIDED "AS IS" AND "AS AVAILABLE," WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, NON-INFRINGEMENT, ACCURACY, SECURITY, OR AVAILABILITY.

We do not warrant that the Extension will be uninterrupted, error-free, secure, or free of bugs, or that any transaction will be processed correctly, promptly, or at all. You use the Extension entirely at your own risk.

7. Limitation of Liability — You Assume All Risk

To the maximum extent permitted by applicable law, in no event shall the developer be liable for any claim, loss, or damages of any kind — direct, indirect, incidental, consequential, special, or exemplary — including but not limited to:

• Loss of funds or digital assets, for any reason.
• Loss of your seed phrase, private keys, or password.
• Failed, delayed, incorrect, duplicated, or unauthorized transactions.
• Sending funds to the wrong address, wrong chain, or wrong token — whether due to your own error or a bug in the Extension.
• Bugs, defects, or vulnerabilities in the Extension's code.
• Outages, errors, delays, or misconduct of any third-party provider (see Section 5), including Circle, the relayer, RPC providers, or any blockchain network itself.
• Any other cause arising from or in connection with the Extension or your use of it.

This applies whether the claim is based in contract, tort, negligence, strict liability, or any other legal theory, and regardless of whether we were advised of the possibility of such damages. You assume all risk associated with using self-custodial software to transact on public blockchains.

Nothing in this section is intended to exclude any liability that cannot lawfully be excluded (such as for fraud or willful misconduct); where a jurisdiction does not permit certain exclusions, this section applies to the maximum extent that jurisdiction allows.

8. License

The Extension's source code is source-available under an MIT License with a Commons Clause restriction. In short: you may read, audit, and modify the code, but you may not sell the software or offer it (or a substantially similar derivative) as a competing commercial product or service. The full license text is reproduced below and governs and takes precedence over this summary:

Copyright (c) 2026 Sigma9

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

“Commons Clause” License Condition v1.0

The Software is provided to you by the Licensor under the License, as defined
below, subject to the following condition.

Without limiting other conditions in the License, the grant of rights under
the License will not include, and the License does not grant to you, the right
to Sell the Software.

For purposes of the foregoing, “Sell” means practicing any or all of the
rights granted to you under the License to provide to third parties, for a fee
or other consideration (including without limitation fees for hosting or
consulting/support services related to the Software), a product or service
whose value derives, entirely or substantially, from the functionality of the
Software. Any license notice or attribution required by the License must also
include this Commons Clause License Condition notice.

Software: sigma9-extension
License: MIT with Commons Clause
Licensor: Sigma9

9. Availability — Not Offered in the European Union / EEA / United Kingdom

The Extension is not offered to, and may not be used by, persons located in or resident of the European Union, the European Economic Area (EEA), or the United Kingdom. By installing or using the Extension you represent and warrant that you are not located in, and are not a resident of, any of those jurisdictions.

Sigma9 is developed by an independent individual with no legal entity and no capacity to take on the registrations and ongoing compliance obligations those jurisdictions impose on software and financial-technology providers. Accordingly, the Extension is simply not made available there. We cannot and do not verify your location; your confirmation is relied upon entirely as your own representation, and if you access the Extension from a prohibited jurisdiction in breach of this section, you do so unlawfully and entirely at your own risk.

10. Changes to These Terms

We may update these Terms from time to time, for example when adding support for additional chains or changing which third-party providers are used. The date at the top of this document indicates the last revision. Continued use of the Extension after a change to these Terms constitutes your acceptance of the revised Terms. If you do not agree with a change, your only recourse is to stop using the Extension.

11. Termination

You may stop using the Extension at any time by uninstalling it. Because the Extension is self-custodial, uninstalling it does not affect your funds on-chain — you retain access to them as long as you retain your seed phrase, independently of the Extension itself.

We may discontinue, modify, or restrict the Extension, or its availability in any jurisdiction, at our sole discretion and without notice.

12. Contact

For questions or feedback about these Terms, use the feedback form at sigma9.app/feedback.

We do not maintain a public support email to reduce spam. Please use the form above.

These Terms of Service are the authoritative version for the Sigma9 browser extension.

They are published at a stable public URL — https://sigma9.app/terms/extension — and are referenced from the Chrome Web Store listing and inside the Extension. Separate terms may cover the Sigma9 mobile app; this document applies only to the browser extension.

Sigma9 — gasless USDC only. Keys stay on your device. Use at your own risk.