Spider is a concurrency-first crawling engine written in Rust. It streams pages as they arrive, renders JavaScript only on pages that need it, and scales from a single script to a distributed fleet without changing your code. The same engine runs Spider Cloud, so you can prototype locally and move to managed infrastructure with one config change.
Start in the cloud
The hardest part of crawling at scale isn't the code. It's the proxies, headless browsers, and constant anti-bot churn. Spider Cloud runs all of that for you behind the same API.
Get a free API key → (no card required)
[dependencies]
spider = { version = "2", features = ["spider_cloud"] }
use spider::configuration::{SpiderCloudConfig, SpiderCloudMode};
use spider::website::Website;
let cloud = SpiderCloudConfig::new("sk-...")
.with_mode(SpiderCloudMode::Smart); // proxy by default, stealth scrape when blocked
let mut website = Website::new("https://example.com")
.with_spider_cloud_config(cloud)
.build()?;
Smart mode routes through proxies first and escalates to a stealth /scrape only on pages that fight back, so you pay for bypass only where it's needed.
Or run it locally
No key, no service. Just the crawler.
[dependencies]
spider = "2"
use spider::{tokio, website::Website};
#[tokio::main]
async fn main() {
let mut website = Website::new("https://example.com");
let mut rx = website.subscribe(16);
tokio::spawn(async move {
while let Ok(page) = rx.recv().await {
println!("{} {}", page.status_code, page.get_url());
}
});
website.crawl().await;
website.unsubscribe();
}
Pages stream in as they're fetched. The crawler finds the links, stays inside the limits you set, and stops on its own.
How it works
Spider runs HTTP-first and launches headless Chrome only when a page needs JavaScript. Both the HTTP and Chrome paths stream, so pages come back as they're fetched instead of batching at the end. The same API drives one async task or a distributed worker fleet, and the concurrency model doesn't change between them. Proxies, retries, rate limiting, and stealth are built in.
Install
| You want… | Run |
|---|---|
| Rust library | cargo add spider |
| Command-line tool | cargo install spider_cli |
| Node.js package | npm i @spider-rs/spider-rs |
| Python package | pip install spider_rs |
| MCP server (Claude, Cursor, …) | cargo install spider_mcp |
| Managed crawling | spider.cloud |
Configuration
Every option has a sensible default, so set only what you need.
let mut website = Website::new("https://example.com")
.with_limit(50) // concurrent requests
.with_depth(10) // how deep to follow links
.with_delay(500) // pause between requests (ms)
.with_respect_robots_txt(true)
.with_subdomains(true)
.with_user_agent(Some("MyBot/1.0"))
.with_stealth(true)
.build()
.unwrap();
Full reference in the Configuration docs.
For JavaScript-heavy sites, enable features = ["chrome"] and call crawl_smart(). Spider tries HTTP first and only launches Chrome on pages that need it.
Use cases
Teams use Spider to feed the open web into vector stores for LLM and RAG pipelines, monitor sites for SEO and price changes, export pages as Markdown, JSON, or WARC, and drive headless Chrome for AI browsing agents. There are 50+ runnable examples to start from.
Learn more
- Guides for recipes and integrations
- API docs for every option and method
- Discord for questions and ideas
- Issues for bugs and feature requests
Contributing
PRs welcome. See CONTRIBUTING.md.
cargo test -p spider # unit tests
RUN_LIVE_TESTS=1 cargo test # live network tests
License
MIT.