> For AI agents: the documentation index is at https://sdk.nimbusprivacy.xyz/llms.txt, and every page is available as Markdown at its URL with .md appended. # Glossary (/resources/glossary) Terms are in alphabetical order. Each has its own link, so you can point to it from your own docs. The [protocol glossary](https://docs.nimbusprivacy.xyz/resources/glossary) goes deeper. ### Account signature The one message a user's wallet signs to open their private account. Every key of the account is derived from it, so the SDK treats it as a secret. ### Commitment A value that fixes some data without revealing it. Each new note's commitment is published on chain, while the note itself stays encrypted. The `commitment` option is something else: Solana's confirmation level. ### Committee The services that check and sign every payment before the pool accepts it: the guardian nodes, the screener, the fee enclave and the data endorser. Their signatures are combined into one. ### Context The object a payment runs in, made from a session by `createDepositContext` and its siblings. It picks the pool and the committee nodes the payment uses. ### Coordinator A service that can make a payment's requests to the committee and the relayer on the browser's behalf. The SDK uses it only with `route: "coordinator"`. ### Deposit Moving tokens from a user's wallet into a private balance, theirs or another user's. ### Gateway token The token that lets your app use Nimbus's services on mainnet. A session sends it to the gateway's services and nowhere else. To get one, email [dev@umbraprivacy.com](mailto:dev@umbraprivacy.com) or reach out to any Umbra team member. ### Identity A user's registered entry in the pool: one value that commits to their keys and their platform wallet. Registering publishes it. ### Indexer The service a sync reads new notes and spends from. ### Intent The device's record of a payment it has started. These docs call it a payment in progress. It stays until the payment lands or can no longer land. ### Lease The hold a payment in progress puts on the notes it spends, so no other payment spends them too. Leased notes count as `reserved`. ### Merge A Private Send to the user's own account that combines several notes into one. The SDK runs merges first when the three largest notes cannot cover a payment. ### Note The unit of a private balance: an amount of one token, owned by one private account. A private balance is the sum of its unspent notes. ### Nullifier A value a payment publishes to mark a note spent. Nobody can tell which note it marks without the owner's keys. ### Pending Funds paid to a user that cannot be spent yet. A new deposit is pending until Solana finalizes it. ### Platform wallet A second Solana address the SDK derives from the account signature. Registration binds it to the user's wallet, and deposits pass through it. ### Pool The Solana program that holds every deposited token, under the rules it enforces. Pools are numbered, and the SDK uses the highest open one by default. ### Private account Everything a user holds in Nimbus. The account signature unlocks it on a device. ### Private balance What a user holds in Nimbus, kept on their device. The SDK reads it with `readBalances`. ### Private Send A payment from one private balance to another. The chain shows neither the sender, the recipient, nor the amount. ### Proof A zero-knowledge proof the device builds for each registration and payment. It shows the payment follows the pool's rules without revealing its private details. ### Proving keys The large circuit files the device needs to build proofs. The SDK downloads them once, checks each one's SHA-256, and caches them. ### Registration The one Solana transaction a wallet sends before its first deposit. It publishes the user's identity in the pool. ### Relayer A service that submits withdrawals and Private Sends to Solana and pays their network fee. The user's wallet signs neither. ### Reserved Funds held by a payment in progress. They come back once the payment can no longer land, or when `releaseReservedNotes` frees them. ### Seed The 64-byte secret the SDK derives from the account signature. Every key of the private account comes from it, and closing the session zeroes it. ### Session A private account opened on this device by `openNimbusSession`. It holds the user's keys in memory until `closeNimbusSession`. ### Settlement Where a relayed payment ended up: `landed`, `failed`, `pending` or `not-followed`. By default the SDK follows each payment until it lands. ### Sync Reading the chain and the indexer into the device, so its private balance is current. Only a sync changes what `readBalances` returns. ### Transaction version The Solana transaction format a wallet signs. Payments use version 1 by default, and version 0 for wallets that cannot sign version 1. ### Withdraw Moving tokens from a private balance to any Solana address. ### Zone A numbered group of notes whose own signer must approve payments into or out of it. Zone 0 has no signer, and every payment uses it by default. ## Next - [Don't confuse](https://sdk.nimbusprivacy.xyz/resources/dont-confuse): Six pairs that sound alike and behave differently. - [Types](https://sdk.nimbusprivacy.xyz/reference/types): Every type the SDK exports. Last updated 21 October 2026