> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/zhcndoc/bun/llms.txt
> Use this file to discover all available pages before exploring further.
# Bun APIs
> Explore Bun's built-in APIs for common JavaScript tasks
Bun provides a set of built-in APIs that make common JavaScript tasks faster and easier. These APIs are available globally without imports and are optimized for performance.
## Core APIs
High-performance HTTP server with WebSocket support
Fast file I/O operations with streaming support
Write files, sockets, or stdout with automatic type conversion
Launch child processes with full control over stdio
## Database & Storage
Fast SQLite database with prepared statements
Unified SQL API for PostgreSQL, MySQL, and SQLite
High-performance Redis client
S3-compatible object storage client
## Utilities
JavaScript bundler with tree-shaking
Transpile TypeScript and JSX to JavaScript
Call native C/C++/Rust/Zig code from JavaScript
Fast hashing functions (wyhash, xxHash, CRC32, SHA)
## Performance Features
All Bun APIs are designed for speed:
* **Zero-copy operations**: File reads and writes use efficient memory operations
* **Streaming support**: Handle large files without loading into memory
* **Native implementations**: Written in Zig for maximum performance
* **Optimized allocations**: Smart memory management reduces garbage collection
## Example: Using Multiple APIs
Here's an example that combines several Bun APIs:
```typescript server.ts theme={null}
import { Database } from "bun:sqlite";
const db = new Database("mydb.sqlite");
db.run("CREATE TABLE IF NOT EXISTS visits (count INTEGER)");
db.run("INSERT INTO visits VALUES (0)");
Bun.serve({
port: 3000,
async fetch(req) {
// Increment visit counter
const result = db.query("UPDATE visits SET count = count + 1 RETURNING count").get();
// Read HTML file
const html = Bun.file("index.html");
// Return response with counter
return new Response(await html.text().replace("{{count}}", result.count), {
headers: { "Content-Type": "text/html" }
});
},
});
console.log("Server running at http://localhost:3000");
```
## Global Objects
Bun extends the global namespace with several utility objects:
### Bun
The main `Bun` namespace contains most APIs:
```typescript theme={null}
Bun.version // Bun version string
Bun.revision // Git commit SHA
Bun.env // Environment variables
Bun.main // Path to entrypoint file
Bun.sleep(ms) // Sleep for milliseconds
Bun.sleepSync(ms) // Synchronous sleep
Bun.which(bin) // Find executable in PATH
Bun.peek(promise) // Check promise status without awaiting
```
### import.meta
Enhanced with Bun-specific properties:
```typescript theme={null}
import.meta.dir // Directory of current file
import.meta.file // Filename of current file
import.meta.path // Full path to current file
import.meta.main // Is this the entrypoint?
import.meta.url // File URL of current module
import.meta.resolve(specifier) // Resolve module path
```
See [import.meta documentation](/api/utils#importmeta) for more details.
## Node.js Compatibility
Bun implements most Node.js built-in modules. See [Node.js Compatibility](/runtime/nodejs-compat) for details.
## Web APIs
Bun implements web standards like fetch, WebSocket, and Streams. See [Web APIs](/runtime/web-apis) for details.
## Next Steps
Build high-performance web servers
Read and write files efficiently
Work with SQLite databases
Browse all runtime APIs