> ## Documentation Index
> Fetch the complete documentation index at: https://sdk.umbraprivacy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Types & Interfaces

> SDK type system (V18): branded types U64/U128/U256, Bn254FieldElement, X25519PublicKey. Integration with @solana/kit Address and TransactionSignature. Function types via the named subpath of each operation family.

## Anza Solana Kit Types

The SDK is built on top of `@solana/kit` and shares its core types directly. You do not need to import `@solana/kit` yourself — these types flow through the SDK's own types naturally — but it helps to know where they come from:

* [`Address`](https://github.com/anza-xyz/solana-web3.js/blob/main/packages/addresses/src/address.ts) — a base58-encoded public key string. Every `mint`, `destinationAddress`, and user-address parameter in the SDK is an `Address`.
* [`TransactionSignature`](https://github.com/anza-xyz/solana-web3.js/blob/main/packages/transaction-messages/src/transaction-message.ts) — a base58-encoded signature string. Returned by every operation that submits a transaction.
* `SignableTransaction` / `SignedTransaction` — the versioned transaction types passed to `IUmbraSigner.signTransaction`.
* `GetLatestBlockhash`, `GetEpochInfo` — RPC function types used in the `deps` of most factory functions.

If you are writing unit tests or building a custom RPC layer, the [`@solana/kit` documentation](https://github.com/anza-xyz/solana-web3.js) is the primary reference for these types.

## Function Types

Every returned function has a named type exported from the **same subpath** as its factory. There is no separate `@umbra-privacy/sdk/interfaces` re-export in V18 — types ship alongside their factories.

```typescript theme={null}
import type {
  // Deposit family
  ATAIntoETADirectDepositorFunction,
  ATAIntoReceiverBurnableStealthPoolNoteCreatorFunction,
} from "@umbra-privacy/sdk/deposit";

import type {
  // Withdrawal family
  ETAIntoATAWithdrawerFunction,
} from "@umbra-privacy/sdk/withdrawal";

import type {
  // Burn family
  BurnableStealthPoolNoteScannerFunction,
  ReceiverBurnableStealthPoolNoteIntoETABurnerFunction,
  SelfBurnableStealthPoolNoteIntoETABurnerFunction,
  SelfBurnableStealthPoolNoteIntoATABurnerFunction,
} from "@umbra-privacy/sdk/burn";

import type { UserRegistrationFunction } from "@umbra-privacy/sdk/registration";
import type {
  QueryUserAccountFunction,
  QueryEncryptedBalanceFunction,
} from "@umbra-privacy/sdk/query";
```

This is useful when you build a factory function once and store it in React state or a context:

```typescript theme={null}
import { useState, useEffect } from "react";
import type { ATAIntoETADirectDepositorFunction } from "@umbra-privacy/sdk/deposit";
import { getATAIntoETADirectDepositorFunction } from "@umbra-privacy/sdk/deposit";

const [deposit, setDeposit] =
  useState<ATAIntoETADirectDepositorFunction | null>(null);

useEffect(() => {
  if (client) {
    setDeposit(() => getATAIntoETADirectDepositorFunction({ client }));
  }
}, [client]);
```

The full inventory of factory + function types mirrors the operation families above. See the [Reference](/reference/overview) for the complete list.