# Femtos Terms of Service and Terms of Sale

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 https://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 (https://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 (https://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
(https://femtos.xyz/accounts/pricing):

| Usage | Credits |
|---|---|
| one REST call | 1 |
| one WebSocket message delivered | 0.1 |
| one heavy call (listed on the pricing page, e.g. long fill or order histories, long candle spans, bridges, wallet endpoints) | 20 |
| one webhook delivery | 1 (plus 0.1 per extra event in the same delivery) |
| status, identity and OpenAPI endpoints | free |

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. **Counting periods.** Free credits, pay-as-you-go price bands and spending caps are counted per calendar month
in UTC. A plan's included credits are counted per paid period of the plan, from its start or renewal date to the next
one (section 11).

6.4. **Spending cap.** You may set a monthly spending cap. Once it is reached, usage is no longer charged that month,
your key's throughput falls back to the free level and heavy calls are refused (HTTP 402), until the next month or
until you raise the cap. A top-up does not lift 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; its
API key and management secret are given **only once, in the answer to that payment** (the same payment sent again is
served without them). **A later payment without a key from the same wallet credits the same Account and replaces its
API key** (the previous key stops working; the new key, too, is given only in the answer to that payment), since
paying from the wallet proves you control it. A key is replaced at most 5 times an hour: past that, the payment is
credited and the current key stays in force.

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 paid period (one
month from the plan's start or renewal date), 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
(https://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 (https://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.