Node.js Built-in APIs

Deno provides comprehensive support for Node.js built-in modules and globals, enabling seamless migration of Node.js applications and libraries. These APIs follow Node.js specifications and provide familiar functionality for developers transitioning from Node.js.

Key Features Jump to heading#

• Built-in Module Support: Access Node.js modules using node: prefix (e.g., import fs from "node:fs")
• Global Objects: Node.js global objects available in npm package scope
• Compatibility Layer: Seamless interoperability with existing Node.js code
• Performance: Native implementations optimized for Deno runtime

Core Modules Jump to heading#

File System Jump to heading#

• node:fs - File system operations (read, write, watch, stats)
• node:fs/promises - Promise-based file system API
• node:path - Cross-platform path utilities

Network & HTTP Jump to heading#

• node:http - HTTP server and client functionality
• node:https - HTTPS server and client with TLS support
• node:http2 - HTTP/2 server and client implementation
• node:net - TCP networking utilities
• node:dns - DNS resolution and lookup functions

Process & System Jump to heading#

• node:process - Process information and control
• node:os - Operating system utilities and information
• node:child_process - Spawn and manage child processes
• node:cluster - Multi-process clustering support

Crypto & Security Jump to heading#

• node:crypto - Cryptographic functionality (hashing, encryption, certificates)
• node:tls - TLS/SSL secure communication layer

Data & Streams Jump to heading#

• node:stream - Stream interfaces (readable, writable, transform)
• node:buffer - Binary data handling with Buffer class
• node:zlib - Data compression and decompression
• node:string_decoder - Decode buffers to strings

Utilities Jump to heading#

• node:util - Utility functions (promisify, inspect, types)
• node:events - Event emitter pattern implementation
• node:url - URL parsing and formatting utilities
• node:querystring - Query string utilities
• node:assert - Assertion testing support

Development & Testing Jump to heading#

• node:vm - Virtual machine contexts for code execution
• node:repl - Read-Eval-Print Loop functionality
• node:inspector - V8 inspector integration for debugging

Global Objects Jump to heading#

Node.js global objects are available in the npm package scope and can be imported from relevant node: modules:

• Buffer - Binary data manipulation
• process - Process information and environment
• global - Global namespace object
• __dirname / __filename - Module path information
• Web Standards - fetch, URL, TextEncoder, crypto, and more

Usage Examples Jump to heading#

Basic Module Import Jump to heading#

import fs from "node:fs";
import { readFile } from "node:fs/promises";
import path from "node:path";

// Synchronous file reading
const data = fs.readFileSync("file.txt", "utf8");

// Asynchronous file reading
const content = await readFile("file.txt", "utf8");

// Path manipulation
const fullPath = path.join("/users", "documents", "file.txt");

HTTP Server Jump to heading#

import http from "node:http";

const server = http.createServer((req, res) => {
  res.writeHead(200, { "Content-Type": "text/plain" });
  res.end("Hello from Node.js API in Deno!");
});

server.listen(3000, () => {
  console.log("Server running on port 3000");
});

Crypto Operations Jump to heading#

import crypto from "node:crypto";

// Generate hash
const hash = crypto.createHash("sha256");
hash.update("Hello World");
const digest = hash.digest("hex");

// Generate random bytes
const randomBytes = crypto.randomBytes(16);

Compatibility Jump to heading#

Node compatibility is an ongoing project. Most core Node.js APIs are supported with high fidelity. For detailed compatibility information:

• View our Node.js compatibility guide
• Check Node.js test results for specific test coverage
• Report compatibility issues on GitHub

Migration from Node.js Jump to heading#

When migrating from Node.js to Deno:

1. Update imports: Use node: prefix for built-in modules
2. Check compatibility: Verify your dependencies work with Deno
3. Use npm specifiers: Import npm packages with npm: prefix
4. Review permissions: Configure Deno's permission system as needed

For more guidance, see our migration guide.