# Glossary

> Every LOPW term in one place, from stake and terms to predicates, epochs and key versions, with links to where each is specified.

*LOPW documentation · Start here.* Canonical page: https://lopw.com/docs/start/glossary.html · This Markdown twin: https://lopw.com/docs/start/glossary.md · Index of all pages: https://lopw.com/llms.txt · Everything in one file: https://lopw.com/llms-full.txt

Short definitions, alphabetical. Each links to the page where the term is defined precisely.

- **Active**: Service state: stake is at or above `min_stake`. The only state in which offers are issued and the buyer SDK pays. [States](https://lopw.com/docs/protocol/bond-registry.html#states)
- **allowed_status**: P4 parameter: the HTTP statuses the seller may charge for. A receipt with any other status proves a breach. [P4](https://lopw.com/docs/protocol/predicates.html#p4)
- **Bond Registry**: The contract that holds stake per service and stores each service’s terms versions and signing keys. Only the Claims contract may slash. [Reference](https://lopw.com/docs/protocol/bond-registry.html)
- **Buyer**: The agent or app that pays per request. The receipt names the buyer, and any payout goes to that address.
- **Chain binding**: The chain-specific parts of LOPW: encoding, signature scheme, contract functions and the payment-rail binding. Stellar is the first. [Bindings](https://lopw.com/docs/protocol/bindings.html)
- **Claim**: One transaction submitting a signed offer and receipt (plus a second receipt for P1) to the Claims contract. Outcome: paid, rejected, or an error with nothing recorded. [Claims](https://lopw.com/docs/protocol/claims.html)
- **Claim window**: Seconds after `served_at` during which a claim may be filed. Part of the terms; at most 24 hours, at most one hour when P6 is offered.
- **Claims contract**: Verifies evidence, applies the seven checks, calls the validator, and pays or rejects. [Claims](https://lopw.com/docs/protocol/claims.html)
- **Closed**: Service state after a full withdrawal. No offers, no claims. Final.
- **data_as_of**: Receipt field: Unix seconds the data was true as of; 0 when not applicable. Drives P3.
- **Domain separation**: The type tag, network ID and registry address hashed in front of every signed body, so a signature is valid for one type, one network and one deployment only. [Hashing and signing](https://lopw.com/docs/protocol/hashing-and-signing.html)
- **Epoch (slash epoch)**: A period one unbonding delay long during which total slashes may not exceed 50% of the stake held at its start. [Slash rate limit](https://lopw.com/docs/protocol/bond-registry.html#slash-rate-limit)
- **Facilitator**: The x402 service that verifies and settles the payment. Unchanged by LOPW.
- **Fee (protocol fees)**: A one-off registration fee and an annual fee on stake, in the stake token, paid to a treasury. Both may be zero. [Fees](https://lopw.com/docs/protocol/bond-registry.html#fees)
- **Key version**: Index of a service’s Ed25519 signing key. Rotation retires the old version with a timestamp; receipts served before it stay verifiable. [Rotate a key](https://lopw.com/docs/guides/rotate-key.html)
- **max_claim**: Offer field: the most a single receipt can pay out. The payout is `min(max_claim, stake remaining)`, and never above the launch limit `max_payout` if one is set.
- **min_stake**: A service parameter set at registration: the stake below which the service is Suspended. At least 100 USDC.
- **NotProven / NotVerifiable**: The two reasons a validator can give for not proving a breach. Both are recorded on-chain as a rejected claim; neither penalises anyone.
- **Offer (warranty offer)**: The seller’s signed promise for one call, carried in the 402 response under `extensions.lopw`. [Fields](https://lopw.com/docs/protocol/offer-and-receipt.html#offer)
- **offer_nonce**: 32 random bytes that make every offer hash unique. The buyer SDK refuses to pay an offer it has already paid.
- **Oracle (SEP-40)**: An on-chain price feed with `price(asset, timestamp)` and `decimals()`. P6 reads one named in the terms. [P6](https://lopw.com/docs/protocol/predicates.html#p6)
- **payment_reference**: Receipt field: the settlement transaction hash. Together with `service_id` it keys the one-paid-claim-per-payment rule.
- **Pending**: Service state after registration until deposits reach `min_stake`. No offers can exist, so stake can be withdrawn at once.
- **Predicate**: One breach condition a contract can decide from the evidence alone. Six exist: P1 Equivocation, P2 Terms mismatch, P3 Stale data, P4 Bad status, P5 Size limit, P6 Oracle deviation. [Predicates](https://lopw.com/docs/protocol/predicates.html)
- **Receipt (service receipt)**: The seller’s signed statement of what it served and under which offer, carried in `PAYMENT-RESPONSE` under `extensions.lopw`. [Fields](https://lopw.com/docs/protocol/offer-and-receipt.html#receipt)
- **request_hash / response_hash**: SHA-256 bindings of the request (method, path with query, body hash) and of the response body. The buyer SDK recomputes both.
- **Seller**: Runs a paid API, stakes the bond, signs offers and receipts with a dedicated signing key.
- **Service**: One registered API with its own stake, terms versions, signing keys and state, identified by a 32-byte `service_id`.
- **Signing key**: An Ed25519 key separate from the seller’s account. It signs offers and receipts and cannot move stake.
- **Slash**: The registry transferring part of a service’s stake to a buyer on a proven claim. Callable only by the Claims contract.
- **Stake (bond)**: USDC a seller locks per service in the Bond Registry. The only money a claim can pay from; a service’s total payouts can never exceed it.
- **Suspended**: Service state when a slash or a fee takes stake below `min_stake`. No new offers; claims still paid while stake remains.
- **Terms**: A service’s list of predicates with parameters plus a claim window. Hashed into `terms_hash`; old versions stay readable so old receipts can still be claimed. [Fields](https://lopw.com/docs/protocol/offer-and-receipt.html#terms)
- **Time lock**: The 26-hour delay on admin changes to who may slash, which validator decides a predicate, fees and loosened limits, so every seller can withdraw first. [Time locks](https://lopw.com/docs/protocol/bond-registry.html#time-locks)
- **Unbonding**: Service state while a full exit waits out the unbonding delay: the largest claim window ever registered plus one hour. Stake stays slashable.
- **Untrusted response**: The buyer SDK’s verdict on a receipt that fails verification (bad signature, wrong offer, buyer, payment, hashes or status). Not claimable.
- **Validator**: A contract with one function, `validate(terms, offer, receipt, extra)`, that decides one predicate. The Claims contract keeps an allowlist of validators by predicate ID.
- **x402**: The HTTP payment protocol LOPW extends. The offer and receipt travel in its v2 extension slot named `lopw`; verify and settle are unchanged. [x402 extension](https://lopw.com/docs/protocol/x402.html)