Spider - High-Performance Web Crawler and Scraper in Rust
Get web data for AI agents and LLMs with a concurrency-first, streaming crawler that renders JavaScript on demand.
Evidence shows: configuration options (with_limit, with_delay, with_respect_robots_txt) indicate some least privilege control; but no user confirmation mechanism (e.g., confirmation dialogs or approval flows). Data flow transparency: README describes page streaming and configuration, but does not detail data flow or processing details. Sensitive data handling: no explicit mention of handling sensitive data (e.g., API keys), but examples use API keys without secure storage advice. Dependency security: cargo-audit workflow exists, with explicit ignore of a known vulnerability (RUSTSEC-2026-0187), but only reachable via optional feature, no mitigation. External effects: crawler makes requests to external sites, but no explicit default robots.txt or rate limiting (though with_respect_robots_txt option exists). Rollback: no rollback mechanism mentioned. Source attribution: no explicit statement on content source or copyright.
Evidence shows: README and configuration examples are consistent, code structure clear, good self-consistency. Dependency availability: dependencies managed via crates.io, Cargo.lock likely present, but no offline or mirror solution. Failure messages: no detailed error handling or failure message examples.
Evidence shows: README explicitly targets AI agents and LLMs, provides multiple use cases (RAG, monitoring, export). Capability boundaries: describes HTTP-first, on-demand JS rendering, but no explicit limits or boundaries. Trigger precision: no explicit trigger conditions or precise control. Environment fit: supports Rust, Node, Python, MCP, adaptable to multiple environments.
Evidence shows: clear information architecture, README, docs links, examples directory. Install notes detailed, covering multiple languages. Naming stability: crate names and API naming consistent. Examples and FAQ: 50+ examples, but no FAQ. Known limitations: not explicitly listed. License: MIT, copyright notice clear. Versioning and changelog: version numbers present, but no changelog. Maintenance responsibility: SECURITY.md and contributing guide, but no explicit maintainers.
Evidence shows: output usability: supports multiple output formats (Markdown, JSON, WARC), page streaming. Marginal value: high-performance crawler and cloud service integration, unique value. Cost-benefit: local free, cloud has cost, but no detailed cost analysis.
Evidence shows: performance claims in README lack benchmark data or test results. Cross-source verification: no third-party verification. Fact-inference separation: README mixes facts and inferences without clear distinction.
- No user confirmation mechanism, may automatically execute crawling operations.
- Sensitive data handling (e.g., API keys) lacks secure storage advice.
- Known dependency vulnerability (RUSTSEC-2026-0187) is ignored without mitigation.
- Performance claims lack benchmark data support.
- No changelog provided, version update information opaque.
What does this agent do, and when should you use it?
Spider is a concurrency-first web crawling engine written in Rust, designed to quickly crawl and stream web data. It prioritizes HTTP requests and only launches headless Chrome when a page requires JavaScript, improving efficiency. The project offers a Rust library, CLI, Node.js and Python packages, and supports managed crawling via Spider Cloud. The engine includes built-in concurrency, rate limiting, retries, proxies, and stealth features, and can scale from a single script to a distributed fleet. Spider is suitable for building data pipelines for LLM and RAG, monitoring, data export, and AI browsing agents.
Spider asynchronously crawls websites, automatically discovering links and respecting crawl boundaries. It uses HTTP clients first and launches headless Chrome when JavaScript is needed. Pages are streamed back as soon as they are fetched, and users can subscribe to receive them. Configuration options include concurrency limit, crawl depth, delay, robots.txt respect, subdomain handling, user agent, and stealth mode. It can export content in Markdown, JSON, or WARC formats. It runs locally or via Spider Cloud, which provides proxy and auto-unblocking. All operations are performed through the Rust API or CLI.
- AI/LLM developers extracting web data from large volumes of pages to feed vector stores for RAG pipelines.
- SEO teams monitoring website changes, tracking rankings, or watching competitor updates.
- Price monitoring systems that regularly scrape product pages and compare prices.
- Researchers or analysts exporting web content as Markdown or JSON for processing or archiving.
- AI browsing agents driving headless Chrome to interact with dynamic websites.
- Teams needing high-concurrency crawling, scaling from a single script to a distributed cluster without code changes.
What are this agent's strengths and limitations?
- Concurrency-first design delivers high throughput and performance.
- Streams pages as they are fetched, enabling real-time processing.
- Built-in anti-bot measures, proxies, rate limiting, and retries.
- Multi-language support: Rust, Node.js, Python, CLI.
- Flexible deployment: local or managed via Spider Cloud.
- Primarily for Rust developers; other languages may have limited features.
- JavaScript rendering requires headless Chrome, adding resource overhead.
- For complex anti-bot scenarios, may rely on Spider Cloud's paid unblocking feature.
- Documentation is extensive but some advanced configs require reading Rust docs.
- Legal compliance for web scraping is the user's responsibility.
How do you install or deploy this agent?
To use as a Rust library, run cargo add spider in your project. For JavaScript rendering, enable the 'chrome' feature in Cargo.toml. Alternatively, install the CLI with cargo install spider_cli, use Node.js via npm i @spider-rs/spider-rs, or Python via pip install spider_rs.
How do you use this agent?
In Rust code, create a Website instance, set the target URL and configuration (such as concurrency and depth), then call crawl() or crawl_smart() to start crawling. Subscribe to receive streamed page data. Example:
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();
}