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

# SDK authentication

The SDK does not use Bloxchain API keys. Authentication means **how your app connects to Ethereum** and **which wallet signs** governed operations.

## Read-only vs write access

| Client                | Use for                                |
| --------------------- | -------------------------------------- |
| `PublicClient` (viem) | Reading contract state, receipts, logs |
| `WalletClient` (viem) | Signing and sending transactions       |

Most SDK wrappers accept a `PublicClient` for reads and require a `WalletClient` for writes.

## Wallet and signer setup

**Development**

```bash
RPC_URL=https://...
PRIVATE_KEY=0x...   # never commit; use a dedicated test key
ACCOUNT_ADDRESS=0x...  # your AccountBlox (or clone) address
```

**Production**

* Use a secure secret store (HSM, KMS, vault)—not `.env` in source control
* Prefer hardware or institutional signing for high-value operations
* Run separate keys for requester, approver, and broadcaster roles when policy requires separation

## Role alignment

The connected wallet must hold the on-chain role your action requires (Owner, Broadcaster, or a custom RuntimeRBAC role). The SDK cannot grant permissions off-chain.

Check effective permissions on-chain or use [My access](/platform-bloxchain.app/overview/my-access.md) in bloxchain.app for the same contract.

## Meta-transactions (EIP-712)

Approvers sign structured data off-chain; a **Broadcaster** wallet submits on-chain. The SDK provides EIP-712 helpers that must match the contract domain—see [Core patterns](/developers/sdk-core-patterns.md) and [Meta-transactions](/protocol/meta-transactions.md).

## bloxchain.app sign-in

Hosted app sign-in (email, optional 2FA) is separate from SDK integration. The app does not expose API keys for contract calls; operators use wallet connection in the browser.

## Next steps

* [Installation](/getting-started/installation.md)
* [Quickstart](/getting-started/quickstart.md)
* [Core patterns](/developers/sdk-core-patterns.md)


---

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