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

# Overview

> Pure runtime bytecode without constructor or metadata

## Type Definition

[Branded](/getting-started/branded-types) [`Uint8Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array) representing pure runtime bytecode without constructor logic or compiler metadata.

```typescript theme={null}
import type { brand } from '@tevm/voltaire/brand';

export type RuntimeCodeType = Uint8Array & {
  readonly [brand]: "RuntimeCode";
};
```

Runtime code is the actual bytecode executed when calling a contract after deployment. It excludes:

* Constructor logic
* Solidity compiler metadata
* Creation-time initialization

## Quick Reference

<Tabs>
  <Tab title="Create">
    ```typescript theme={null}
    import * as RuntimeCode from '@tevm/voltaire/RuntimeCode';

    // From hex string
    const code = RuntimeCode.from("0x6001600155");

    // From Uint8Array
    const code = RuntimeCode.from(new Uint8Array([0x60, 0x01, 0x60, 0x01, 0x55]));
    ```
  </Tab>

  <Tab title="Compare">
    ```typescript theme={null}
    // Compare runtime codes
    if (RuntimeCode.equals(code1, code2)) {
      console.log("Runtime codes match");
    }

    // Convert to hex
    const hex = RuntimeCode.toHex(code);
    ```
  </Tab>
</Tabs>

## API Methods

### Constructors

* [`from(value)`](./from) - Create from hex string or Uint8Array
* [`fromHex(hex)`](./fromHex) - Parse hex string (with or without 0x prefix)

### Utilities

* [`toHex(code)`](./toHex) - Convert to hex string
* [`equals(a, b)`](./equals) - Compare equality

## Usage Patterns

### Contract Verification

```typescript theme={null}
import * as RuntimeCode from '@tevm/voltaire/RuntimeCode';
import * as ContractCode from '@tevm/voltaire/ContractCode';

// Get deployed code and strip metadata
const deployed = ContractCode.from(await provider.getCode(address));
const deployedRuntime = ContractCode.stripMetadata(deployed);

// Compare with compiled runtime code
const expectedRuntime = RuntimeCode.from(compiledRuntimeCode);

if (RuntimeCode.equals(deployedRuntime, expectedRuntime)) {
  console.log("Contract verified: runtime code matches");
} else {
  console.log("Verification failed: runtime code differs");
}
```

### Bytecode Analysis

```typescript theme={null}
import * as RuntimeCode from '@tevm/voltaire/RuntimeCode';
import * as Bytecode from '@tevm/voltaire/Bytecode';

const runtime = RuntimeCode.from(runtimeBytecode);

// Analyze runtime code
const analysis = Bytecode.analyze(runtime);
console.log(`Instructions: ${analysis.instructions.length}`);
console.log(`Valid: ${analysis.valid}`);
console.log(`Jump destinations: ${analysis.jumpDestinations.size}`);

// Pretty print
const disassembly = Bytecode.prettyPrint(runtime, {
  showGas: true,
  showStack: true,
});
console.log(disassembly);
```

### Comparing Contract Versions

```typescript theme={null}
import * as RuntimeCode from '@tevm/voltaire/RuntimeCode';

// Compare different versions of a contract
const v1 = RuntimeCode.from(contractV1RuntimeCode);
const v2 = RuntimeCode.from(contractV2RuntimeCode);

if (!RuntimeCode.equals(v1, v2)) {
  console.log("Runtime code changed between versions");
  console.log(`v1 hex: ${RuntimeCode.toHex(v1)}`);
  console.log(`v2 hex: ${RuntimeCode.toHex(v2)}`);
}
```

## Related

* [ContractCode](/primitives/contract-code) - Full deployed bytecode
* [InitCode](/primitives/init-code) - Creation bytecode
* [Bytecode](/primitives/bytecode) - Bytecode analysis tools
* [Metadata](/primitives/metadata) - Compiler metadata

## Specification

* [Ethereum Yellow Paper](https://ethereum.github.io/yellowpaper/paper.pdf) - EVM execution model
* [EVM Opcodes](https://www.evm.codes/) - Instruction reference
* [Solidity Internals](https://docs.soliditylang.org/en/latest/internals/layout_in_storage.html) - Contract structure