# web_techstack Tech stack — detect what a website is built with. Fetches a public URL and fingerprints the web technologies it is built with — a BuiltWith / Wappalyzer-style detector. Returns a list of detected technologies, each with its categories, a confidence (high, medium, low), an optional version, and the evidence that matched. Covers JavaScript frameworks and libraries (React, Vue.js, Angular, Svelte, jQuery), web frameworks / static site generators (Next.js, Nuxt.js, Gatsby, Remix, SvelteKit, Astro, Hugo), CMS and website builders (WordPress, Drupal, Joomla, Ghost, Wix, Squarespace, Webflow), e-commerce (Shopify, WooCommerce, Magento, BigCommerce), analytics, ad pixels, and tag managers (Google Analytics, Google Tag Manager, Meta Pixel, LinkedIn, Bing, TikTok/Pinterest/Reddit pixels, Segment, Hotjar, Microsoft Clarity), CDNs, UI frameworks and fonts, payments (Stripe, PayPal, Klarna), live chat, marketing automation, A/B testing, consent management, CAPTCHAs (reCAPTCHA, hCaptcha, Turnstile), video, and search. It also inspects response headers (from a plain HTTP fetch) to identify the web server (nginx, Apache, IIS), the CDN / hosting provider (Cloudflare, CloudFront, Fastly, Vercel, Netlify), and the server-side language / framework (PHP, ASP.NET, Ruby on Rails, Django, Laravel, Express). Results are directional, not exhaustive. The render fetch strategy is one of browser (headless browser that executes JavaScript — the default, so client-injected scripts like analytics, tag managers and pixels are detected), auto (Chrome-impersonated HTTP, escalating to a real browser only when blocked or JS-rendered), or http (HTTP only, no JavaScript — fastest, but sees only the server HTML); defaults to browser. Only public pages are supported; respect each site's terms of use and robots directives. Agent View of the PolicyLayer registry record for `web_techstack`. HTML page: https://policylayer.com/tools/crawlora-mcp/web-techstack ## Facts - Tool: `web_techstack` - Server: Crawlora (`crawlora-mcp`) — https://policylayer.com/tools/crawlora-mcp.md - Install: `npx -y crawlora-mcp` - Homepage: https://www.npmjs.com/package/crawlora-mcp - Risk category: Read (Low risk) - Registry record: grade F, identity unverified - Server rate-limited: no - Parameters: 1 (1 required) - Recommended policy verdict: Allowed ## Parameters | Parameter | Type | Required | Description | | --- | --- | --- | --- | | `request` | object | yes | Target URL (and optional render strategy) | Parameters from the server's own tool schema. ## Example call (MCP tools/call, JSON-RPC 2.0) ```json { "jsonrpc": "2.0", "id": 1, "method": "tools/call", "params": { "name": "web_techstack", "arguments": { "request": {} } } } ``` ## Why web_techstack is rated Low Even though web_techstack only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing. ## Use case AI agents call web_techstack to retrieve information from Crawlora without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere. ## Recommended policy (PolicyLayer) Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Crawlora: ```json { "version": "1", "default": "deny", "tools": { "web_techstack": {} } } ``` ## Other tools on Crawlora (727) - `anime_title` — Execute — https://policylayer.com/tools/crawlora-mcp/anime-title.md - `coingecko_new_coins` — Execute — https://policylayer.com/tools/crawlora-mcp/coingecko-new-coins.md - `justwatch_discover` — Execute — https://policylayer.com/tools/crawlora-mcp/justwatch-discover.md - `justwatch_new` — Execute — https://policylayer.com/tools/crawlora-mcp/justwatch-new.md - `manga_title` — Execute — https://policylayer.com/tools/crawlora-mcp/manga-title.md - `steam_charts_top_releases` — Execute — https://policylayer.com/tools/crawlora-mcp/steam-charts-top-releases.md - `yahoo_finance_ticker_history` — Execute — https://policylayer.com/tools/crawlora-mcp/yahoo-finance-ticker-history.md - `airbnb_host` — Read — https://policylayer.com/tools/crawlora-mcp/airbnb-host.md - `airbnb_host_listings` — Read — https://policylayer.com/tools/crawlora-mcp/airbnb-host-listings.md - `airbnb_host_reviews` — Read — https://policylayer.com/tools/crawlora-mcp/airbnb-host-reviews.md - `airbnb_room` — Read — https://policylayer.com/tools/crawlora-mcp/airbnb-room.md - `airbnb_room_calendar` — Read — https://policylayer.com/tools/crawlora-mcp/airbnb-room-calendar.md - `airbnb_room_reviews` — Read — https://policylayer.com/tools/crawlora-mcp/airbnb-room-reviews.md - `airbnb_search` — Read — https://policylayer.com/tools/crawlora-mcp/airbnb-search.md - `amazon_product` — Read — https://policylayer.com/tools/crawlora-mcp/amazon-product.md - `amazon_search` — Read — https://policylayer.com/tools/crawlora-mcp/amazon-search.md - `amazon_suggest` — Read — https://policylayer.com/tools/crawlora-mcp/amazon-suggest.md - `anime_character` — Read — https://policylayer.com/tools/crawlora-mcp/anime-character.md - `anime_character_search` — Read — https://policylayer.com/tools/crawlora-mcp/anime-character-search.md - `anime_rankings` — Read — https://policylayer.com/tools/crawlora-mcp/anime-rankings.md - `anime_search` — Read — https://policylayer.com/tools/crawlora-mcp/anime-search.md - `anime_title_characters` — Read — https://policylayer.com/tools/crawlora-mcp/anime-title-characters.md - `anime_title_recommendations` — Read — https://policylayer.com/tools/crawlora-mcp/anime-title-recommendations.md - `anime_title_staff` — Read — https://policylayer.com/tools/crawlora-mcp/anime-title-staff.md - `apple_podcasts_charts` — Read — https://policylayer.com/tools/crawlora-mcp/apple-podcasts-charts.md - `apple_podcasts_episodes_search` — Read — https://policylayer.com/tools/crawlora-mcp/apple-podcasts-episodes-search.md - `apple_podcasts_search` — Read — https://policylayer.com/tools/crawlora-mcp/apple-podcasts-search.md - `apple_podcasts_show` — Read — https://policylayer.com/tools/crawlora-mcp/apple-podcasts-show.md - `apple_podcasts_show_episodes` — Read — https://policylayer.com/tools/crawlora-mcp/apple-podcasts-show-episodes.md - `appstore_app` — Read — https://policylayer.com/tools/crawlora-mcp/appstore-app.md - …and 697 more: https://policylayer.com/tools/crawlora-mcp.md ## For agents This record is a snapshot. Live verdicts and the full registry: - Check every server in your MCP config at once: `npx -y policylayer stack` - Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md) - Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events` --- Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=crawlora-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/crawlora-mcp