Terms of Service

These Terms cover your use of stamp.gridcoin.club (the Service from here on). The Service is free, open-source software run as a non-commercial public good by @gridcat and friends. Source under MIT at github.com/gridcoin-community/stamp.gridcoin.club.

By using the Service in any way (web, API, the GitHub Action, or anything we ship under the same name) you agree to these Terms. If you do not agree, do not use the Service. Where the law requires capital letters or specific phrasing for enforceability we have used them; everywhere else we have tried to keep the prose plain.

The Service is a Proof of Existence tool. Your browser computes a SHA-256 hash of a file you choose, sends that hash to the Service's API, and the Service writes it into a Gridcoin OP_RETURN transaction under a public protocol (5ea1ed on mainnet, f055aa on testnet). The file itself never leaves your device. The on-chain record is permanent and globally readable.

The Service is not:

• a Qualified Trust Service Provider under eIDAS Regulation (EU) 910/2014, and the timestamps it produces are not qualified electronic timestamps under Article 42 of that regulation;
• a notary, bailiff, court witness, certifying authority, or any other officer of any legal system;
• a payment service, money transmitter, money services business, virtual-asset service provider, crypto-asset service provider, custodian, exchange, or broker;
• a provider of legal, tax, accounting, or evidentiary advice.

The Service publishes opaque hashes and renders chain state. You provide the hashes; the Gridcoin chain stores them; the Service is a convenience layer in between. Anyone can run their own instance against the same protocol, and anyone can run a Gridcoin node and index the same OP_RETURN payloads independently of this site.

A stamp proves one fact: this exact 32-byte SHA-256 hash appeared inside a Gridcoin block at a specific block height, with the block's timestamp. From that, and from holding the original file, you can show that the file existed in that exact form by that block time, because flipping a single bit changes the hash.

A stamp does notprove who controlled or authored the file, that the file is original or unique, that the stamp is the earliest existence of the file, that the submitter has any rights in the file, or that the file's contents are accurate, lawful, or reliable. If you need to show authorship or intent on top of existence, pair the stamp with a signature, a contract, or other corroborating evidence.

On evidentiary value: in the EU, a stamp is a non-qualified electronic timestamp under Article 41(1) of eIDAS. It is admissible as evidence and may not be denied legal effect solely on the grounds that it is electronic or non-qualified, but it does not enjoy the automatic presumption of accuracy granted to qualified timestamps under Article 42. Its weight in any given case is for the court to decide. (See, for example, the Tribunal Judiciaire de Marseille decision of March 2025 accepting a public-blockchain timestamp as proof of copyright anteriority.) Italy's Article 8-ter of Law 12/2019 grants blockchain timestamps eIDAS-equivalent effect by statute. In the United States, blockchain records are admissible under Federal Rule of Evidence 901(b)(9) and under DLT-evidence statutes in Vermont, Arizona, Ohio, Washington, and Delaware, among others.

None of the foregoing is legal advice. If a stamp matters to a real dispute, talk to a lawyer in the relevant jurisdiction.

You may use the Service only if using it is lawful in your jurisdiction, and you are not located in, a national of, or owned or controlled by a person in any country or region subject to comprehensive UN, EU, UK, Swiss, or US sanctions, and you are not on any of those authorities' sanctions lists. You confirm each of these by using the Service.

You agree not to use the Service:

• to deceive a court, regulator, counterparty, or insurer about the time at which a file existed;
• to register hashes derived from child sexual abuse material, non-consensual intimate imagery, or other material whose creation or possession is criminal in your jurisdiction or in the operator's jurisdiction;
• to register hashes derived from personal data of another person unless you are the data subject or you have a lawful basis under applicable data-protection law (see Privacy and personal data below);
• to circumvent sanctions, export controls, or other applicable trade laws;
• to launch, assist, or facilitate denial-of-service against the Service, the Gridcoin network, or any third-party dependency;
• to bypass rate limits, scrape beyond what the public API permits, or otherwise abuse the operator's wallet by inducing fee burn at scale.

The Service has no way to inspect what a hash represents (a SHA-256 hash is opaque by design), so prevention of the above is on you. The operator may refuse, rate-limit, or terminate access for any reason it considers appropriate, including suspected violation of these rules.

The Service stores the bare minimum needed to operate. For each stamp: the hash, hash type, protocol version, transaction id, block, raw transaction, and the time values that surround it. Nothing about you. There are no accounts, no email addresses, no real names.

Operational logs (IP address, user-agent, request timing) are retained on a rolling window for security and capacity planning, then deleted. Aggregate page-view counts come from Plausible, which does not set tracking cookies and does not follow you across sites.

About the on-chain hash. Hashes published on the Gridcoin chain are public, immutable, and not under the operator's control. The operator cannot retrieve, redact, or remove them. If you do not want a hash to be public forever, do not stamp it.

Hashes of personal data. Under the European Data Protection Board's Guidelines 02/2025 on processing personal data through blockchain technologies, a hash derived from personal data may itself retain personal-data status. The Service has no way to tell whether the hash you submit derives from personal data; that determination, and any lawful basis for processing it under GDPR or similar regimes, is your responsibility. If you are unsure, do not stamp the hash.

Right to erasure. Where you have a right to erasure under GDPR Article 17 or an equivalent regime, the operator can remove the hash from its own database and from this site's indexed display, subject to the legitimate-interest balancing in Article 17(3). The operator cannot remove the hash from the Gridcoin chain — that is the nature of a public ledger and part of why the Service is useful as evidence. Other people running their own Gridcoin nodes will continue to index the payload independently.

Lawful requests. The operator will respond to lawful requests from competent authorities to the extent technically possible. The operator does not collect submitter identifiers and so has no submitter PII to disclose; the on-chain record is outside the operator's technical control.

The Service's code is published under the MIT licence at github.com/gridcoin-community/stamp.gridcoin.club. The MIT licence governs your rights in the source. These Terms govern your use of this hosted instance at stamp.gridcoin.club.

The on-chain protocol is public. Anyone can run their own stamp instance and write conformant payloads, and anyone can run a Gridcoin node and index existing ones, with no permission from the operator. The timestamp survives even if this site does not.

This service is provided as-is, without any warranty of any kind, express or implied. This includes the stamping web application, the public API, and the Gridcoin Stamp GitHub Action. We make no guarantees about availability, correctness, durability, or fitness for a particular purpose.

To the maximum extent permitted by law, the operator disclaims all warranties, express or implied, including merchantability, fitness for a particular purpose, non-infringement, accuracy, completeness, durability, availability, security, and quiet enjoyment. The operator does not warrant that the service will be uninterrupted, error-free, secure, or free of malware, that any defect will be corrected, or that any timestamp produced will be admitted, given any specific weight, or accepted as proof in any court, tribunal, regulatory proceeding, or other forum.

The operator does not warrant the operation, security, or continuity of the Gridcoin network, of any wallet software, of any blockchain explorer, or of any other third-party dependency. The operator does not warrant against forks, reorganisations, or attacks on the underlying chain that could affect a stamp's representation or apparent time.

Some jurisdictions do not allow the exclusion of certain warranties. To the extent any warranty cannot lawfully be excluded, it is limited to the minimum scope and shortest duration permitted by that law, and your exclusive remedy is the discontinuation of your use of the Service.

To the maximum extent permitted by law, the operator will not be liable for any indirect, incidental, special, consequential, exemplary, or punitive damages, including lost profits, lost revenue, lost data, lost case outcomes, lost GRC, lost opportunities, business interruption, or substitute-procurement cost, arising out of or relating to the Service, however caused, whether in contract, tort (including negligence), strict liability, or any other theory, even if the operator has been advised of the possibility of such damages.

Without limiting the foregoing, the operator will not be liable for: (i) damages arising from reliance on a stamp in any dispute, proceeding, negotiation, transaction, or publication; (ii) the rejection or limited weight given to a stamp by any court, tribunal, regulator, or counterparty; (iii) outages, errors, forks, reorgs, or attacks on the Gridcoin network; (iv) outages or errors of any wallet, explorer, or third-party tool integrated with or linked from the Service; (v) consequences of your loss or compromise of files, keys, or proof URLs.

Nothing in these Terms excludes or limits liability that cannot lawfully be excluded or limited, including liability for death or personal injury caused by negligence, fraud, fraudulent misrepresentation, or any non-waivable consumer-protection right under the law of your habitual residence.

You agree to indemnify and hold the operator harmless from any claim, demand, loss, or expense (including reasonable legal fees) arising from your use of the Service in violation of these Terms or of any applicable law.

Governing law. These Terms, and any dispute arising out of them or out of your use of the Service, are governed by the laws of [Operator’s principal place of business], without regard to conflict-of-laws principles. The courts of [Operator’s principal place of business] have exclusive jurisdiction. If you are a consumer habitually resident in the European Union, the United Kingdom, or another jurisdiction whose consumer-protection law cannot lawfully be displaced by contract, you also retain the protections of the mandatory law of your residence.

Changes to these Terms. The operator may update these Terms at any time. The effective date at the bottom of this page reflects the current version. Your continued use of the Service after the effective date of a change constitutes acceptance of the updated Terms; if you do not accept, stop using the Service.

Severability and waiver. If any provision of these Terms is held invalid or unenforceable, the rest remains in full effect. The operator's failure to enforce any right or provision is not a waiver of that right or provision.

Force majeure. The operator is not liable for delay or failure to perform caused by events beyond its reasonable control, including outages or attacks on the Gridcoin network, blockchain forks or reorganisations, hosting-provider failures, governmental or regulatory action, court orders, war, civil unrest, sanctions, embargoes, fire, flood, extreme weather, pandemic, and disease.

No agency. Nothing in these Terms creates a partnership, agency, employment, joint venture, or fiduciary relationship between you and the operator.

Entire agreement. These Terms, together with the policies referenced from them and the licence governing the source code, are the entire agreement between you and the operator regarding the Service.

Contact. General queries: gridcat [at] proton [dot] me. Abuse reports, lawful-process correspondence, IP infringement notices, and authority requests: gridcat [at] proton [dot] me. The operator accepts service of process and authority correspondence in English at this address.

Effective date: 2026-05-07