# Lelantos SDK

> Client SDK for the Lelantos Multi-Asset Shielded Pool — shielded transfers, swaps, and client-side proving on EVM. TypeScript, published as `@lelantos-org/sdk` (this documentation describes v0.47.0).

Every page below is plain markdown. Start with Concepts and Quickstart; the whole guide is also available as a single file at https://docs.lelantos.xyz/llms-full.txt. Every TypeScript example is typechecked against this SDK version at build time; lines under `// setup` are scaffolding (`declare`d inputs standing in for your own values), the rest is the usage being shown. Import from the subpath an example uses — subpaths are part of the API.

## Getting started

- [Installation](https://docs.lelantos.xyz/guide/installation.md): `@lelantos-org/sdk` is published to **GitHub Packages**, not the public npm registry.
- [Quickstart](https://docs.lelantos.xyz/guide/quickstart.md): This page runs a complete round trip in one script: shield, transfer, and unshield.

## Concepts

- [Concepts](https://docs.lelantos.xyz/guide/concepts.md): The SDK hides the cryptography, but four concepts determine how its API behaves.
- [How it fits together](https://docs.lelantos.xyz/guide/system.md): The SDK communicates with **contracts** on an EVM chain and three **backend services** that index and relay transactions.
- [Glossary](https://docs.lelantos.xyz/guide/glossary.md): Terms used throughout this guide and the API reference.

## Wallet

- [Connecting a wallet](https://docs.lelantos.xyz/guide/wallet.md): `connect(options)` returns a `WalletApi`: a frozen object of bound methods (`deposit`, `transfer`, `withdraw`, `quoteSwap`, `sync`, `balance`, `state`, …).
- [Networks](https://docs.lelantos.xyz/guide/networks.md): A network preset contains the deployment details `connect()` needs: chain id, pool and relayer addresses, service URLs, and the circuit's tree depth.
- [Addresses](https://docs.lelantos.xyz/guide/addresses.md): A shielded address is a **bech32m** string with the human-readable prefix `lelantos` and a 112-byte payload, `d || pk_d || pk || ck_d`.
- [Amounts and assets](https://docs.lelantos.xyz/guide/amounts.md): A value can be held in three unit spaces.

## Transactions

- [Deposit](https://docs.lelantos.xyz/guide/deposit.md): A deposit moves tokens from a public ERC-20 balance into the shielded pool.
- [Transfer](https://docs.lelantos.xyz/guide/transfer.md): A transfer moves value between shielded addresses.
- [Withdraw](https://docs.lelantos.xyz/guide/withdraw.md): A withdrawal spends shielded notes and pays a public EVM address.
- [Swap](https://docs.lelantos.xyz/guide/swap.md): A swap exchanges one shielded asset for another in a single atomic operation:
- [Names](https://docs.lelantos.xyz/guide/names.md): A handle is a short name, such as `alice`, that publishes one of an account's shielded addresses.
- [Fees](https://docs.lelantos.xyz/guide/fees.md): An operation can incur three separate costs, each charged by a different party.

## Notes & sync

- [Syncing](https://docs.lelantos.xyz/guide/sync.md): A note is spendable only when the wallet has three things locally: the note, the Merkle tree containing it, and the nullifier set showing whether it is spent.
- [Balances and state](https://docs.lelantos.xyz/guide/state.md): A wallet exposes what it knows two ways: `balance(asset)`, an async read that splits one asset's value by what a spend can reach, and `state()`, a synchronous immutable snapshot for rendering without polling.
- [Note management](https://docs.lelantos.xyz/guide/notes.md): The pool stores notes, not balances.
- [Watch-only wallets](https://docs.lelantos.xyz/guide/watch-only.md): A viewing key gives read access to a shielded account without the ability to spend.

## Privacy

- [Denominations](https://docs.lelantos.xyz/guide/denominations.md): A withdrawal publishes its gross amount, `publicOut`.
- [Privacy checklist](https://docs.lelantos.xyz/guide/privacy.md): The pool hides which notes a transaction spends, who receives a transfer, and transfer amounts.

## Integration

- [Package subpaths](https://docs.lelantos.xyz/guide/subpaths.md): `@lelantos-org/sdk` publishes eleven typed entry points.
- [x402 payments](https://docs.lelantos.xyz/guide/x402.md): x402 uses HTTP `402 Payment Required` as a protocol: the server answers an unpaid request with the terms it accepts, the client pays, and the request is repeated with a receipt attached.
- [Browser usage](https://docs.lelantos.xyz/guide/browser.md): The SDK runs in browsers with the same API as on Node.
- [Node usage](https://docs.lelantos.xyz/guide/node.md): `connect()` detects Node and configures the prover, scanner, and HTTP clients for it.
- [Custom storage](https://docs.lelantos.xyz/guide/storage.md): The wallet persists three kinds of state, each through its own interface:
- [Pluggable interfaces](https://docs.lelantos.xyz/guide/interfaces.md): Every external dependency of a wallet is an interface with a working default.
- [Chain adapters](https://docs.lelantos.xyz/guide/chain-adapter.md): The chain port is the SDK's only interface to the chain.

## Operations

- [Errors](https://docs.lelantos.xyz/guide/errors.md): Every wallet method rejects with a `WalletError`, or with the `reason` of an `AbortSignal` you passed.
- [Logging](https://docs.lelantos.xyz/guide/logging.md): The SDK emits no log output by default.
- [Troubleshooting](https://docs.lelantos.xyz/guide/troubleshooting.md): Common symptoms, their causes, and fixes.
- [Benchmarks](https://docs.lelantos.xyz/guide/benchmarks.md): Proof generation is the most expensive client-side operation.

## Internals

- [Architecture](https://docs.lelantos.xyz/guide/architecture.md): The SDK is organized in tiers.
- [Building transactions manually](https://docs.lelantos.xyz/guide/primitives.md): The wallet API covers every operation on this page.

## API reference

Generated from the package's type declarations, one page per export.

- [@lelantos-org/sdk/advanced](https://docs.lelantos.xyz/reference/advanced/index.md)
- [@lelantos-org/sdk](https://docs.lelantos.xyz/reference/index/index.md)
- [@lelantos-org/sdk/internal](https://docs.lelantos.xyz/reference/internal/index.md)
- [@lelantos-org/sdk/primitives](https://docs.lelantos.xyz/reference/primitives/index.md)
- [@lelantos-org/sdk/protocol](https://docs.lelantos.xyz/reference/protocol/index.md)
- [@lelantos-org/sdk/prover](https://docs.lelantos.xyz/reference/prover/index.md)
- [@lelantos-org/sdk/services](https://docs.lelantos.xyz/reference/services/index.md)
- [@lelantos-org/sdk/watch](https://docs.lelantos.xyz/reference/watch/index.md)
- [@lelantos-org/sdk/workers/prover](https://docs.lelantos.xyz/reference/workers/prover/index.md)
- [@lelantos-org/sdk/workers/scanner](https://docs.lelantos.xyz/reference/workers/scanner/index.md)
- [@lelantos-org/sdk/x402](https://docs.lelantos.xyz/reference/x402/index.md)

## Optional

- [Full guide](https://docs.lelantos.xyz/llms-full.txt): every guide page above, concatenated
- [Reference index](https://docs.lelantos.xyz/reference/index.md)