Femtos Terms of Service and Terms of Sale

Version françaiseMarkdown

Last updated 2026-10-22.

These terms govern the use of the Femtos data APIs and the purchase of API credits and plans. They are also available in French at femtos.xyz/fr/terms. For Consumers living in France the French version prevails in case of conflict; for everyone else the English version prevails.

1. Who we are

The Services are provided by Femtos ("Femtos", "we"), contact: contact@femtos.xyz.

Femtos is being registered as a company in France. Its full legal identity (company name, registration number, registered office) will be published on femtos.xyz as soon as the registration is complete, and these terms updated accordingly. Until then, contact@femtos.xyz reaches us for any question, request or notice under these terms.

2. Definitions

• Services: the Femtos REST and WebSocket APIs (including /api, /v1, /ws, the Hyperliquid-compatible /info and /hl/ws endpoints, MCP), webhooks, the website femtos.xyz, docs.femtos.xyz and the account pages.
• Data: the information returned by the Services, derived from public blockchains (HyperCore, HyperEVM, Elysium and others) and third-party sources.
• Account: what an API key belongs to. An Account is created by email signup, by agent signup (no email, proof of work) or by a first x402 payment.
• API key: the secret token that authenticates calls. Management secret: the second secret given to accounts without an email, needed to rotate, delete or unfreeze.
• Credits: the unit in which usage is measured and charged (section 6).
• Customer, you: the person or entity that holds an Account. Consumer: a natural person acting for purposes outside their trade, business, craft or profession. Professional: any other Customer.
• Agent: software (for example an AI agent) that signs up or calls the Services on behalf of a person.

3. Acceptance, Professionals and Consumers

3.1. Creating an Account, calling the Services with an API key, or paying for credits means you accept these terms and the privacy policy (femtos.xyz/privacy).

3.2. Agents. An Agent acts on behalf of the person or entity that deploys it (its operator). The operator is the Customer: it is bound by these terms and responsible for every call, payment and action of its Agent, including those made with an API key or management secret the Agent obtained by itself.

3.3. Professionals and Consumers. These terms apply to both. Clauses marked [B2B] apply only to Professionals, clauses marked [B2C] only to Consumers. Nothing in these terms limits the rights that consumer law gives Consumers where they live in the European Union. If you use the Services for your trade or business (for example a trading firm, a fund, a software company, a self-employed developer), you are a Professional.

3.4. You must be at least 18 years old, or the age of majority where you live, to buy credits or a plan.

4. Accounts and API keys

4.1. Signup. Email signup: one Account per mailbox. Agent signup: an agent_name and an optional owner_email, after a proof of work; the response returns the API key and the management secret once. A limited number of free signups is allowed per network address and per day. The x402 path creates an Account on a wallet's first payment (section 10).

4.2. Keep your secrets safe. The API key and the management secret are shown once. Store them securely, never put them in public code, URLs, logs or client-side apps that third parties can read. Anyone who holds your key can use your credits. You are responsible for all usage made with your key until you freeze or rotate it.

4.3. Freeze, rotate, delete. You can freeze a key at once with the key alone; rotating, deleting or unfreezing requires a confirmation sent by email (Accounts with an email) or the management secret (Accounts without one). Rotating replaces the key: the old one stops working at once. If you lose both the key and the management secret of an Account without an email, we may be unable to give you access back.

4.4. One person, one free tier. Creating several Accounts to multiply the free allowance, or to get around a limit or a suspension, is not allowed.

4.5. Accurate information. An email address you give must be yours and valid. You must keep it up to date if you buy a plan, so that we can reach you about billing.

5. The Services and third parties

5.1. What we provide. Indexed, normalised and derived data about HyperCore, HyperEVM, Elysium and related networks: markets, trades, positions, wallets, bridges, token launches, and the like, as described in the documentation (femtos.xyz). The list of endpoints, fields, channels and data coverage may change.

5.2. Third-party networks. Hyperliquid (HyperCore, HyperEVM), Elysium and every other blockchain, bridge, oracle or protocol whose data we index are third parties. Femtos is independent of them: not affiliated with, endorsed by or acting for the Hyperliquid project, the Hyper Foundation, Kinetiq or the Elysium network. Their outages, forks, reorganisations, upgrades, bugs, data errors or changes of terms may affect the Data and the Services; we are not responsible for them. Compatibility of some endpoints with third-party API formats does not imply any partnership.

5.3. Named wallets. Some answers name a wallet's owner (for example a public trader or fund). A name says who a public source attributes the wallet to, with a confidence level. It is not a verified identity. You must not rely on it as a statement of fact about a person, nor use it to harass, threaten or expose anyone. A person who is named, or wrongly named, can ask for a correction or removal (privacy policy, section 9).

5.4. Beta features. Features marked beta, preview or testnet are provided for evaluation, without any commitment.

6. Credits and prices

6.1. Credits. Usage is measured in credits. Current weights, also shown on the pricing page (femtos.xyz/accounts/pricing):

6.2. Prices. Prices are in US dollars (USD). The prices in force are those shown on the pricing page at the time of purchase (pay-as-you-go price bands per million credits, plan prices, included credits and overage rates). We may change prices for the future. A change never applies to credits already paid for; a plan's new price applies from the next renewal after at least 30 days' notice, and you may cancel before it applies.

6.3. Calendar month. Free credits, included plan credits, price bands and spending caps are counted per calendar month in UTC.

6.4. Spending cap. You may set a monthly spending cap. Once it is reached, usage is no longer charged that month and your key's throughput falls back to the free level until the next month or until you raise the cap.

6.5. Metering. Our records of usage are authoritative unless you show they are wrong. Short overruns that occur before a limit takes effect (a few seconds) are not charged to you.

7. Free tier

7.1. Every Account gets free credits each calendar month (currently 1,000,000) and the free rate limits. No payment is needed.

7.2. When the free credits are used up and no prepaid balance remains, the key is restricted: it keeps the free rate limits and heavy calls are refused (HTTP 402) until you top up or the next month starts.

7.3. The free tier is offered without any commitment of availability or support. We may change its volume or end it with 30 days' notice on the website.

8. Pay-as-you-go: prepaid credits (top-ups)

8.1. Top-ups. You add a USD balance to your Account by paying in USDC: a deposit to your Account's deposit address (section 9) or an x402 credit pack (section 10). Payment by card is not available yet; it will come later, and these terms will be updated before it opens. Usage beyond the monthly free credits is charged against the balance at the price bands in force. Paying more unlocks higher throughput levels shown on the pricing page.

8.2. Nature of the balance. The balance is a prepayment for the Services only. It is not electronic money, a deposit or a wallet: it bears no interest and cannot be withdrawn, transferred to another Account or converted back to money or crypto-assets, except as provided in 8.4.

8.3. Validity. The balance has no expiry date while the Account exists.

8.4. Refunds. Top-ups are non-refundable, except:

• [B2C] under the right of withdrawal (section 12);
• if we end the Services, or close your Account without a breach on your part: the unused balance is refunded;
• if a payment was credited twice or made by mistake, or in other cases where the law requires it;
• at our discretion, in other cases.

When a refund is due, it is paid in USDC only to the address that paid, on the same network, after we have verified it, minus network fees.

8.5. Account deletion. Deleting your Account ends the contract. If your balance is positive, the deletion goes ahead only after you have explicitly confirmed that you give up that balance; the unused balance is then lost. Contact us before deleting if you believe a refund is due under 8.4.

9. Payment in USDC

9.1. Crypto only. Payments are made in USDC only: deposits (this section) and x402 packs (section 10). Card payments are not offered yet.

9.2. USDC deposits. Each Account gets its own deposit address, the same on HyperEVM and HyperCore, shown in the dashboard and the API. Only the following are credited:

• HyperEVM: Circle USDC at the contract shown in the documentation, sent to your deposit address;
• HyperCore: USDC spot transfers, sends or bridge deposits to your deposit address.

9.3. Your responsibility. You must send the right token, on the right network, to the right address. A transfer of another token, on another network, below the minimum (currently USD 1), or to an address that is not your deposit address is not credited, and we have no duty to recover or return it. Network fees, and Hyperliquid's activation fee when it applies to a first transfer, are borne by you and reduce the amount credited. 1 USDC is credited as USD 1.

9.4. Finality. A deposit is credited once it is final on its chain: on HyperEVM after the number of confirmations shown in the documentation (currently 5 blocks), on HyperCore once it is recorded. Blockchain transfers are irreversible: a payment settled on-chain is final and is not refunded, except under 8.4; any refund goes only to the sending address, on the same network.

9.5. Deleted accounts. Funds sent to the deposit address of a deleted Account are not credited automatically. Contact us; we will handle the case by hand and may ask you to prove you control the sending address.

10. x402 credit packs

10.1. Agents can buy credit packs with the x402 protocol, paid in USDC on the networks offered in the 402 answer (currently Base, Arbitrum One and HyperEVM; Elysium once available). Pack amounts are listed in that answer (currently USD 0.01, 0.1, 1, 5 and 20).

10.2. A pack is credited once its payment is settled and verified on its chain. Paid with an API key, it credits that key's Account. Paid without a key, the first payment from a wallet creates an Account bound to that wallet and returns its API key and management secret once; a later payment without a key from the same wallet credits the same Account and replaces its API key (the previous key stops working), since paying from the wallet proves you control it.

10.3. Settlement may go through a third-party facilitator. Its fees are included in the price shown. Sections 8.2 to 8.5 and 9.4 apply to packs.

11. Plans (subscriptions)

11.1. Plans. Monthly plans (currently Builder, Pro and Scale) include a number of credits per calendar month, higher rate limits and an overage rate, as shown on the pricing page. Scale: 600M included credits or more; volumes above the standard Scale plan, and custom terms, are agreed by quote.

11.2. Payment and renewal. A plan is paid in advance, one month at a time, from your prepaid USD balance (funded in USDC, sections 9 and 10). It renews each month on the anniversary date while it is not cancelled and the balance covers its price; if the balance does not cover a renewal, the plan ends at the end of the paid period.

11.3. Cancellation. You can cancel at any time from the dashboard or the API. Cancellation takes effect at the end of the current paid period; the plan remains active until then. Paid periods are not refunded, except under section 12 or where the law requires. Changing plan means cancelling and subscribing again; there is no proration.

11.4. Overage. Usage beyond the included credits of a month is charged at the plan's overage rate from your prepaid balance. Overage the balance does not cover is due and is taken from the balance as soon as it is funded. Unpaid overage is limited each month to 10 % of the plan's monthly price: past that limit, your key is restricted (as in 7.2) until you top up or the next month starts.

11.5. Account deletion. An Account cannot be deleted while a plan is in force (including a cancelled plan until its end date) or while overage remains unpaid.

11.6. [B2B] Late payment. Amounts due are payable on demand. Under articles L441-10 and D441-5 of the French Commercial Code, late payments bear penalties at three times the French legal interest rate and a fixed recovery fee of EUR 40, without prejudice to further compensation. No discount for early payment.

12. [B2C] Right of withdrawal

12.1. 14 days. As a Consumer, you may withdraw from a purchase (top-up, x402 pack or plan) within 14 days of the purchase, without giving reasons, by sending us an unambiguous statement, for example with the model form below, to contact@femtos.xyz.

12.2. Immediate start. Credits are usable, and plans active, as soon as payment is confirmed. By paying, you expressly request that the Services start before the end of the withdrawal period.

• If you withdraw after the Services have started, you owe an amount proportionate to what was supplied until you told us of your withdrawal (article L221-25 of the French Consumer Code): we refund the unused part of the balance, or for a plan the price less the larger of the share of the period elapsed and the share of included credits used.
• You lose the right of withdrawal once the Services have been fully performed before the end of the period, that is once the credits bought are all used, since you requested the start and acknowledged this loss (article L221-28 1°). For digital content not supplied on a tangible medium (for example data files you download), you lose it once the supply has started with your express prior consent and your acknowledgment that you lose the right (article L221-28 13°).

12.3. Refund. We refund within 14 days of your notice, with the same means of payment (USDC to the sending address, on the same network), at no cost to you other than network fees that we cannot avoid.

12.4. Model withdrawal form. "To Femtos, contact@femtos.xyz: I hereby give notice that I withdraw from my contract for the following service: [top-up / pack / plan, date of purchase, Account id or last 4 characters of the API key]. Name and address of the consumer. Date."

13. [B2C] Legal guarantee of conformity

Consumers benefit from the legal guarantee of conformity for digital content and digital services (articles L224-25-12 et seq. of the French Consumer Code): if the Services do not conform to the contract, you may ask us to bring them into conformity and, failing that, for a price reduction or to end the contract with a refund. Write to contact@femtos.xyz.

14. Rate limits and fair use

14.1. Each key has rate limits (requests per second, burst, WebSocket connections, subscriptions, webhook endpoints) that depend on its tier, plan or throughput level, as shown in the documentation and in GET /accounts/agent/me. Calls over the limit are refused (HTTP 429) or connections closed. Unauthenticated access (demo passes, keyless MCP, unpaid x402 challenges) is limited per network address.

14.2. You must not try to circumvent limits, for example by spreading load over several keys or Accounts, or by rotating network addresses.

15. Acceptable use

You must not:

• resell or redistribute the Data: you may build applications, analytics, trading tools and agents on the Data and show results derived from it to your own users. You may not resell, sublicense, redistribute or make available the Data in raw or substantially raw form (for example a feed, a mirror, a dump, or an API that replicates our endpoints), nor give access to your key, to third parties, unless your plan or a written agreement with Femtos expressly allows it;
• use the Services for unlawful purposes, market manipulation, fraud, sanctions evasion or money laundering;
• use the named-wallet data to identify, track, harass, threaten or expose private individuals;
• attack, probe, overload or reverse engineer the Services, bypass authentication or limits, or use the Services to attack others (including through webhook URLs pointing at systems you do not control);
• share your API key publicly, or use another Customer's key;
• misrepresent your relationship with Femtos or use the Femtos name and marks without permission.

You represent that you are not subject to sanctions of the European Union, France, the United Nations or other applicable authorities, and that you do not pay from funds or addresses linked to such sanctions.

16. Webhooks

16.1. You may register HTTPS endpoints that receive signed events. You must control those endpoints; we deliver at least once, with retries, and keep a delivery log for 7 days. An endpoint that answers HTTP 410 or fails repeatedly for more than 24 hours is disabled.

16.2. You are responsible for verifying signatures, for the security of your endpoint and of its signing secret, and for what your systems do with the events.

17. Suspension and termination

17.1. By you. You may stop using the Services and delete your Account at any time (sections 8.5 and 11.5).

17.2. By us. We may freeze or suspend a key or an Account, with notice when practicable, if: you breach these terms (in particular sections 4.4, 14 and 15); a payment turns out to be invalid; your key appears to be compromised; or this is needed to protect the Services, other Customers or third parties, or to comply with the law. We lift the measure once its cause is gone. We may terminate for serious or repeated breach after notice by email (or, without an email, by an answer of the API), or without notice where the law allows. Prepaid amounts are not refunded on a termination for your breach, except for Consumers where the law requires.

17.3. We may end the Services, or the free tier, with 30 days' notice; unused paid balances are then refunded.

18. Data "as is", no investment advice

18.1. The Data is provided "as is" and "as available". It is derived from blockchains and third-party sources that may be incomplete, delayed, reorganised or wrong, and from our own processing, which may contain errors. We do our best to keep it accurate, complete and timely, but we do not warrant that it is.

18.2. No investment advice. The Data and the Services are information only. Nothing in them is investment, financial, legal or tax advice, a recommendation, or an offer to buy or sell any crypto-asset or financial instrument. You alone decide how to use the Data, in particular for trading or automated decisions, and you bear the risks of those decisions. Trading crypto-assets and derivatives involves a high risk of loss.

18.3. You must check the Data before relying on it for any decision with financial or legal consequences.

19. Availability and support

19.1. We aim for continuous availability, but the Services are provided without any service level agreement (SLA) or uptime commitment, whatever the plan or throughput level.

19.2. The Services may be interrupted for maintenance, upgrades, incidents, or events at third parties (networks, hosting, Internet). We announce planned maintenance and changes when practicable on the website and in the changelog (femtos.xyz/changelog).

19.3. Support: contact@femtos.xyz, on a best-effort basis.

20. Intellectual property

20.1. Femtos keeps all rights in the Services, the software, the documentation, the Femtos name and marks, and its databases (including the database producer's rights of articles L341-1 et seq. of the French Intellectual Property Code). Facts recorded on public blockchains belong to no one.

20.2. Subject to these terms and to paying for your usage, we grant you a non-exclusive, non-transferable, worldwide right to use the Data for your own purposes, and to show results derived from it to your users, within the limits of section 15. This right survives termination for Data obtained while your Account was active, except for any redistribution right granted by a plan, which ends with the plan.

20.3. If you send us feedback, we may use it freely.

21. Liability

21.1. [B2B] Femtos is liable only for direct damage proven to result from its breach. Femtos is not liable for indirect damage, including loss of profit, trading losses, loss of opportunity, loss of data or reputational damage. Femtos's total liability, all causes together, is limited to the amounts you paid to Femtos in the 12 months before the event that caused the damage (or EUR 100 for free use). These limits do not apply to gross negligence, wilful misconduct, or where the law forbids them.

21.2. [B2C] Femtos is liable under the law for damage caused by its breach of the contract. It is not liable where the damage results from your own fault, from a third party unconnected with the Services (in particular the networks in section 5.2), or from force majeure, nor for the outcome of investment decisions you make with the Data, which is information only (section 18).

21.3. Force majeure. Neither party is liable for a failure caused by force majeure within the meaning of article 1218 of the French Civil Code. Failures of third-party networks and infrastructure outside our control (section 5.2, hosting providers' regional outages) are treated as such where they meet that definition.

21.4. [B2B] You indemnify Femtos against claims of third parties arising from your breach of section 15.

22. Personal data

We process personal data as described in the privacy policy (femtos.xyz/privacy).

23. Changes to these terms

We may amend these terms. We publish the new version with its date and, for material changes, notify Customers with an email address (and, where practicable, the API) at least 30 days before they apply. If you do not agree, you may cancel your plan and stop using the Services before that date; Consumers may also ask for the refund of their unused balance. Changes required by law or by a third-party network may apply sooner. Adding the seller's legal identity once the company is registered (section 1) is not a material change.

24. Governing law, disputes and mediation

24.1. These terms are governed by French law. [B2C] This does not deprive Consumers living in another EU country of the protection of the mandatory rules of that country.

24.2. Before any legal action, please write to contact@femtos.xyz so that we can try to settle the dispute amicably.

24.3. [B2C] Consumer mediation. If the dispute is not settled within a reasonable time after your written complaint, you may refer it free of charge to a consumer mediator (articles L611-1 et seq. of the French Consumer Code). The name and contact details of our consumer mediator will be published here together with the seller's legal identity (section 1).

24.4. [B2B] Any dispute is submitted to the exclusive jurisdiction of the competent courts of the place of Femtos's registered office, including for summary proceedings or multiple defendants.

24.5. [B2C] You may bring proceedings before the courts of your place of residence or any other court competent under the law.

25. Miscellaneous

If a clause is held invalid, the others remain in force. Our failure to enforce a clause is not a waiver. You may not assign the contract without our consent. These terms, the pricing page in force at the time of purchase and, where applicable, a signed order form or written agreement (which prevails on the points it covers) form the whole agreement.

26. Contact

Femtos. Email: contact@femtos.xyz.