> For the complete documentation index, see [llms.txt](https://docs.baas.sh/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.baas.sh/baas-sdk/resources/exported-types.md).

# Exported types

The SDK is written in TypeScript and ships with full type definitions. No extra `@types` package is needed.

## Types

```ts
import type {
  // Client
  BaasClient,
  BaasClientOptions,
  // Auth & sessions
  BaasSession,
  AuthStateChangeCallback,
  BaasAuthClient,
  EIP1193Provider,
  // Chains
  BaasChain,
  BaasChainsClient,
  ChainChangeCallback,
  // User
  BaasUserClient,
  BaasUser,
  // Errors
  BaasErrorCode,
  BaasApiErrorLevel,
  // Smart contracts — fluent chain
  ContractStep,
  AddressStep,
  FunctionStep,
  TerminalStep,
  SendOptions,
  SimulateOptions,
  EstimateGasOptions,
  // Typed wrapper for overload disambiguation
  TypedValue,
  // Wallet
  BaasWallet,
  BaasTransaction,
  SendTransactionOptions,
  SignMessageOptions,
  GetBalanceOptions,
  // viem re-export
  TransactionReceipt,
} from '@baas/sdk';
```

{% hint style="info" %}
`TransactionReceipt` is re-exported from viem, so you can type the result of `tx.wait()` without installing viem yourself.
{% endhint %}

## Error classes

Error classes are exported as values, so you can use `instanceof`:

```ts
import {
  BaasError,
  BaasAuthError,
  BaasWalletError,
  BaasNetworkError,
  BaasApiError,
} from '@baas/sdk';
```

## Helpers

```ts
import { Typed, Units } from '@baas/sdk';
```

* `Typed` provides ABI type wrappers for disambiguating Solidity overloads when JavaScript can't distinguish scalar types (e.g. `Typed.uint8(100)` vs `Typed.uint256(100)`). See [Disambiguating overloaded functions](/baas-sdk/blockchain/smart-contracts.md#disambiguating-overloaded-functions).
* `Units` converts between human amounts and raw on-chain values (wei, token base units). See [Unit conversion](/baas-sdk/blockchain/units.md).

## Next

* [API reference](/baas-sdk/resources/api-reference.md) — every method, option, and signature.
* [Error handling](/baas-sdk/resources/error-handling.md) — the typed error hierarchy.
* [Integration guides](/baas-sdk/integrations.md) — TypeScript setup and supported environments.


---

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