AlterLab

Why AlterLab Instead of WebFetch or Browser MCP?

Claude's built-inWebFetchtool and open-source browser MCP servers fail on most real-world websites. They cannot bypass Cloudflare, render JavaScript SPAs, or extract structured data.

AlterLab replaces broken fetch tools withone MCP serverthat actually works:

AlterLab uses a multi-tier scraping architecture. It automatically selects the cheapest method capable of fetching each URL:
- Curl($0.0002/req) — Direct HTTP for static pages, RSS feeds, public APIs
- HTTP($0.0003/req) — TLS fingerprint rotation for moderately protected sites
- Stealth($0.0005/req) — Browser impersonation for Cloudflare/DataDome-protected sites
- Light JS($0.0007/req) — Lightweight JS extraction from server-rendered HTML
- Browser($0.001/req) — Full headless Chromium for JavaScript-heavy SPAs

Auto mode starts at Tier 1 and escalates only when blocked. Most websites resolve at Tiers 1-2, so$1 gets you 1,000 to 5,000 scrapesdepending on the sites you target.

Add to your Claude config file (~/.claude.jsonfor Claude Code, or Settings for Claude Desktop):

{ "mcpServers": { "alterlab": { "command": "npx", "args": ](#install-in-claude-desktop--claude-code)["-y", "alterlab-mcp-server@latest"], "env": { "ALTERLAB_API_KEY": "sk_live_your_key_here" } } } }

Add to.cursor/mcp.jsonin your project root:

{ "mcpServers": { "alterlab": { "command": "npx", "args": ["-y", "alterlab-mcp-server@latest"], "env": { "ALTERLAB_API_KEY": "sk_live_your_key_here" } } } }

Add to Windsurf MCP settings (~/.codeium/windsurf/mcp_config.json):

{ "mcpServers": { "alterlab": { "command": "npx", "args": ["-y", "alterlab-mcp-server@latest"], "env": { "ALTERLAB_API_KEY": "sk_live_your_key_here" } } } }

npx -y @smithery/cli install alterlab-mcp-server --client claude

- Sign up free— $1 free balance on signup
- Go toDashboard → API Keysand copy your key
- Paste it into theALTERLAB_API_KEYfield in your MCP config

"Scrape https://www.amazon.com/dp/B0BSHF7WHW and summarize the product"

"Extract the product name, price, and rating from this Amazon page"

"Take a screenshot of our landing page at https://alterlab.io"

"How much would it cost to scrape linkedin.com?"

"Is my Amazon session still valid?"

User: "What's my Prime member price for this product?" Claude: [calls alterlab_list_sessions → finds Amazon session] Claude: [calls alterlab_scrape with session_id for authenticated pricing] Claude: "The Prime member price is $24.99 (public price: $34.99)"

Ask Claude to scrape and analyze websites in real-time:

- "Scrape the top 5 results from this Google search and summarize them"
- "Extract all product prices from this Amazon category page"
- "Compare the pricing pages of these 3 competitors"

Let Cursor or Windsurf fetch live data while building:

- "Scrape this API documentation page and generate TypeScript types from it"
- "Extract the color palette from this website and create a Tailwind config"
- "Screenshot this design and recreate it in React"

- "Scrape this blog post and suggest improvements for SEO"
- "Extract all FAQ entries from this help center and create a structured dataset"
- "Compare our landing page to the competitor's and identify gaps"

Build agentic workflows that watch the web:

- "Check if this product is back in stock"
- "Scrape this page daily and alert me when the price drops below $50"
- "Monitor this job board for new senior engineering positions"

No subscriptions. No monthly minimums. Add balance and use it whenever you need it.

$1 = 5,000 light scrapes.New accounts get $1 free balance on signup.

How do I add web scraping to Claude, Cursor, or Windsurf?

Install the AlterLab MCP server. For Claude Code, runclaude mcp add alterlab -- npx -y alterlab-mcp-server@latestand set yourALTERLAB_API_KEY. For Claude Desktop, Cursor, or Windsurf, add the JSON config block to your MCP settings file. Once configured, your AI assistant can scrape any URL, extract structured data, and take screenshots directly in conversation.

Can Claude scrape websites that are behind Cloudflare or anti-bot protection?

Yes. AlterLab automatically handles Cloudflare, DataDome, PerimeterX, Akamai, and other anti-bot systems. It uses a multi-tier approach that starts with the cheapest method and escalates only when blocked. You don't need to configure anything — anti-bot bypass is fully automatic.

What is an MCP server and how does it work with Claude?

MCP (Model Context Protocol) is Anthropic's open standard for connecting AI assistants to external tools and data sources. An MCP server is a small program that exposes tools — like web scraping — that Claude, Cursor, or Windsurf can call during a conversation. The AlterLab MCP server gives your AI assistant 23 tools: scrape, extract, screenshot, crawl, search, map, batch scraping, session management, beta features, and more.

How is AlterLab different from Firecrawl, ScrapingBee, or Apify MCP servers?

AlterLab starts at $0.0002 per request — 5-20x cheaper than most scraping APIs — because it only uses expensive browser rendering when a site actually requires it. Smart tier escalation means you pay for what each site needs, not the maximum. AlterLab also includes built-in structured data extraction with pre-built profiles (product, article, job posting, etc.) at no extra cost.

Can I scrape Amazon, Walmart, and other e-commerce sites from Claude?

Yes. AlterLab handles all major e-commerce anti-bot protection. Use thealterlab_extracttool withextraction_profile: "product"to get structured JSON: product name, price, currency, rating, review count, availability, and images — ready for analysis, comparison, or data pipelines.

Can Cursor scrape documentation and generate code from it?

Yes. With AlterLab MCP installed in Cursor, you can ask it to scrape API documentation, library docs, or any reference page and generate TypeScript types, API clients, or component code from the live content. This is more reliable than relying on the LLM's training data, which may be outdated.

Does AlterLab MCP work with JavaScript-heavy sites (React, Angular, Vue)?

Yes. Userender_js: trueor setmode: "js"to enable full headless Chromium rendering. AlterLab renders the complete page including all JavaScript, waits for dynamic content to load, then extracts content from the fully rendered DOM. This works for React, Angular, Vue, Next.js, and any other JavaScript framework.

What output format is best for AI and LLM context windows?

Use markdown (the default). It preserves document structure — headings, tables, lists, links — while being 60-80% smaller than raw HTML. Claude, GPT-4, and other LLMs process markdown significantly better than HTML. AlterLab's markdown output is specifically optimized for LLM context windows.

Free-tier accounts have rate limits. Adding any balance removes rate limits. The MCP server includes automatic retry with exponential backoff for transient rate limit errors (429).

Can I use this MCP server for large-scale scraping?

Yes. For parallel scraping, usealterlab_batchto scrape up to 100 URLs in a single request — much faster than sequential calls. For crawling entire domains, usealterlab_crawl. You can also build agentic workflows that scrape many URLs sequentially, or use the[n8n integrationfor workflow automation.

The MCP server returns helpful error messages with suggested next actions: