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

# Set up a TypeScript project

> The project every guide here starts from.

<Steps>
  <Step title="Create the project">
    ```bash theme={null}
    mkdir bridg-app && cd bridg-app
    npm init -y
    npm install @kernlog/bridg-sdk viem dotenv
    npm install -D typescript tsx @types/node
    npx tsc --init
    ```

    `viem` signs on EVM chains. Guides that start from Solana add `@solana/web3.js` and `bs58`.
  </Step>

  <Step title="Add a .env">
    ```bash .env theme={null}
    EVM_PRIVATE_KEY=0x…
    EVM_RPC_URL=https://mainnet.base.org
    ```

    Bridg itself needs no key. The private key is only for signing the transactions Bridg builds; never commit it.
  </Step>

  <Step title="Create the client and a signer">
    ```typescript src/evm.ts theme={null}
    import 'dotenv/config';
    import { createClient, type BuildStep } from '@kernlog/bridg-sdk';
    import { createPublicClient, createWalletClient, http, type Hex } from 'viem';
    import { privateKeyToAccount } from 'viem/accounts';
    import { base } from 'viem/chains';

    export const bridg = createClient();
    export const account = privateKeyToAccount(process.env.EVM_PRIVATE_KEY as Hex);

    const wallet = createWalletClient({ account, chain: base, transport: http(process.env.EVM_RPC_URL) });
    const chain = createPublicClient({ chain: base, transport: http(process.env.EVM_RPC_URL) });

    /** Sign one EVM step from a build and wait for it to be mined. */
    export async function signEvmStep(step: BuildStep): Promise<Hex> {
      if (step.vm !== 'evm') throw new Error(`expected an EVM step, got ${step.vm}`);
      const hash = await wallet.sendTransaction({
        to: step.to as Hex,
        data: step.data as Hex,
        value: BigInt(step.value),
      });
      await chain.waitForTransactionReceipt({ hash });
      return hash;
    }
    ```

    Bridg returns unsigned steps; this is the only place a key is used. Run any script with `npx tsx src/<file>.ts`.
  </Step>
</Steps>

The SDK ships ESM and CommonJS with type declarations. Every type used in the guides is exported: `import type { QuoteResponse, BuildStep, Transfer } from '@kernlog/bridg-sdk'`.