A high-performance website crawler built for serious SEO audits. Targets 1M+ URLs on a single machine, with a dense Screaming Frog–style UI, 150+ SEO issue checks, and zero native dependencies.

✨ What FreeCrawl Does

FreeCrawl crawls your website and checks it for SEO problems — a free, desktop alternative to Screaming Frog. It handles very large sites (1M+ URLs on one machine) and streams the results into a fast, dense table while the crawl is still running.

It runs 150+ SEO checks across 32 tabs — page titles, meta descriptions, headings, duplicate content, broken links, redirects, canonicals, hreflang, structured data, security headers, readability, and more. It can also render JavaScript pages with a real headless browser to capture the final DOM, screenshots, and Core Web Vitals.

Every link type — images, CSS, JavaScript, media, canonicals, pagination, hreflang, AMP, iframes — has its own Crawl and Store switch, so you decide exactly what gets fetched and what gets reported. Right-click any table selection to copy cells, rows, or columns straight to the clipboard.

Pull in real data from Google Search Console, Analytics 4, PageSpeed Insights, and Chrome UX Report, check spelling and grammar with LanguageTool — with a bundled offline dictionary for languages LanguageTool has no rules for, such as Turkish — and run your own AI prompts on each page (OpenAI, Claude, or Ollama). Open several projects side by side, each in its own window running its own crawl, and manage them from a Projects dialog with search, tags, and starter templates.

Export to Excel, CSV, JSON, XML, an HTML report, sitemaps, Google Sheets, or BigQuery, save each project as one compressed file (or a password-protected encrypted file), and export any URL Details sub-table on its own. A built-in MCP server (100+ tools) lets AI agents like Claude drive crawls live and read every result — every action a human can take in the desktop is callable from an agent, and several agents can run in parallel, each in its own isolated crawl session. Everything runs fully local — no telemetry, no cloud, MIT-licensed.

🛠 Tech Stack

Layer	Choice
🟢 Runtime	Node.js 22 LTS+ (ESM-first)
📘 Language	TypeScript 5.7+ strict
🪟 Desktop shell	Electron 41
⚡ Build	electron-vite 5 / Vite 7
🎨 UI	React 19 + Tailwind 3.4 + Zustand 5
📊 Tables	`@tanstack/react-table` + `@tanstack/react-virtual`
🌐 HTTP	undici 8
🔎 HTML parse	cheerio (htmlparser2 fast path)
📥 Queue	p-queue 8
🤖 robots	robots-parser 3
💾 Storage	`node:sqlite` + WAL — zero native deps
📦 Distribution	electron-builder 26

🚀 Quick Start

Tip

End users: download the prebuilt installer from the Releases page — no setup required.

🪟 Windows — easiest path is the .bat launcher

Double-click FreeCrawl-SEO-Tool-Start.bat at the repo root. It verifies Node.js, runs npm install on first launch, then starts the app with npm run dev.

Don't want to install? Grab the portable .exe from the Releases page — runs without installation.

Or manually:

git clone https://github.com/kemalai/FreeCrawl-SEO-Tool.git
cd FreeCrawl-SEO-Tool
npm install
npm run dev

🍎 macOS — Apple Silicon + Intel

Easiest path is the FreeCrawl-SEO-Tool-Start.sh launcher at the repo root — same one-click flow as the Windows .bat (verifies Node, prompts to install on first run, then starts the app).

chmod +x FreeCrawl-SEO-Tool-Start.sh
./FreeCrawl-SEO-Tool-Start.sh

Or manually:

# 1. Install prerequisites (skip any you already have)
brew install node@22 git
xcode-select --install      # Command Line Tools — required once

# 2. Clone and run
git clone https://github.com/kemalai/FreeCrawl-SEO-Tool.git
cd FreeCrawl-SEO-Tool
npm install
npm run dev

If macOS Gatekeeper blocks an unsigned local build ("App is damaged"):

xattr -cr "/Applications/FreeCrawl SEO.app"

🐧 Linux — Debian / Ubuntu / Fedora / Arch

Easiest path is the FreeCrawl-SEO-Tool-Start.sh launcher at the repo root (same as macOS).

Prebuilt installers are available for all three families: .AppImage (universal), .deb (Debian / Ubuntu), and .rpm (Fedora / RHEL).

# 1. Install Node.js 22 LTS (Debian / Ubuntu via NodeSource)
curl -fsSL https://deb.nodesource.com/setup_22.x | sudo -E bash -
sudo apt install -y nodejs git

# Fedora / RHEL : sudo dnf install nodejs:22 git
# Arch          : sudo pacman -S nodejs npm git

# 2. Clone and run
git clone https://github.com/kemalai/FreeCrawl-SEO-Tool.git
cd FreeCrawl-SEO-Tool
npm install
npm run dev

Some headless / minimal distros also need GTK/X11 runtime libs for Electron: sudo apt install -y libgtk-3-0 libnss3 libasound2t64

⌨ CLI (headless crawl)

npx tsc -b apps/cli     # builds the CLI + its workspace packages
node apps/cli/dist/index.js https://example.com --depth 2 --max 500 --out out.csv
node apps/cli/dist/index.js --list urls.txt --out out.json     # list mode + JSON

# Log file analysis — parse an access log into the project for crawl × log reporting
node apps/cli/dist/index.js analyze-logs samples/apache-access.txt --project crawl.seoproject
node apps/cli/dist/index.js analyze-logs access.log --format iis-w3c --verify-bots --json

Sample logs ship in samples/ (apache-access.txt, iis-access.txt) so you can try the Log File Analyzer immediately — in the desktop app, open Log Analyzer → Open Log Analyzer Window… and import one.

CI / CD recipes — ready-to-use GitHub Actions and GitLab CI examples that crawl your site on a schedule, fail the build when broken-URL count exceeds a threshold, and upload the crawl as an artifact. See the CI/CD guide for the exit-code contract and a regression-gate recipe.

📦 Production build (per-platform installers)

npm run build                                  # all packages + desktop + CLI
npm --workspace apps/desktop run build:win     # Windows installer (NSIS) + portable .exe
npm --workspace apps/desktop run build:mac     # macOS DMG (arm64 + x64)
npm --workspace apps/desktop run build:linux   # AppImage / .deb / .rpm

🤖 MCP server — query AND drive crawls from Claude / any MCP client

FreeCrawl ships an MCP (Model Context Protocol) server that exposes the active .seoproject to AI agents over stdio. Two capabilities in one server:

Read-only data access to the SQLite project — runs alongside the desktop app without contention (WAL allows concurrent readers).
Live crawl control — when the desktop app is open, an agent can start / pause / resume / stop crawls and poll progress in real time. This goes through a localhost-only HTTP bridge (127.0.0.1, ephemeral random port, 32-byte Bearer token auth, discovery file written to <userData>/mcp-bridge.json on app launch).

100+ tools — every action a human can take in the desktop is callable from an agent, plus multi-agent session management so several agents can work in parallel. Representative groups:

Group	Tools
📊 Top-level data	`get_summary`, `get_overview_counts`, `top_issues`, `query_urls`, `get_url_detail`
🔬 Per-URL detail sub-tabs	`get_url_source` (raw + rendered + screenshot paths), `get_url_inlinks`, `get_url_outlinks`, `get_url_images`, `get_url_headers`, `get_url_duplicates`, `get_url_analytics`, `get_url_cert`
🧩 Integration rows	`query_gsc`, `query_ga4`, `query_pagespeed`, `query_crux`, `query_spelling`, `get_url_spelling`, `query_ai`, `query_seo`
🔎 Specialised queries	`query_images`, `query_broken_links`, `list_duplicate_clusters`
📈 Reports	`report_status_code_histogram`, `report_indexability_distribution`, `report_content_kind_distribution`, `report_depth_histogram`, `report_response_time_histogram`, `report_inlinks_histogram`, `report_word_count_histogram`, `report_url_length_histogram`, `report_top_urls_by`, `report_top_anchor_texts`, `report_external_domain_health`, `report_image_weight_per_page`, `report_link_position_breakdown`, `report_pages_per_directory`, `report_word_count_per_directory`, `report_sitemap_orphans`, `report_orphan_cross_source`, `report_analytics_coverage`, `report_server_header_breakdown`, `report_query_string_variants`, `report_sitemap_priority_mismatch`, `report_top_words`
📤 Exports & mutations	`export_csv`, `export_json`, `export_xml`, `export_html_report`, `export_tabular`, `export_bulk`, `export_broken_links`, `export_images`, `sitemap_generate`, `sitemap_validate`, `robots_test`, `robots_validate`, `compare_load`, `crawl_add_url`, `respider_urls`, `remove_urls`, `data_delete_by_domain`, `graph_snapshot`, `get_crawl_path`, `url_rewrite_preview`, `extraction_preview`
🔐 Project files	`project_save_as`, `project_save_encrypted`, `project_open_encrypted`
🔌 Integration fetch	`google_auth_status`, `gsc_list_sites`, `gsc_fetch`, `ga4_list_properties`, `ga4_fetch`, `pagespeed_run`, `crux_run`, `spelling_run`, `ai_run`, `seo_run`, `get_fetch_progress`, `cancel_fetch`
⚙ Config & schedule	`get_crawl_config`, `set_crawl_config`, `schedule_get`, `schedule_set`
📁 Project management	`list_projects`, `set_project`, `current_project`
🕷 Crawl control (desktop must be open)	`start_crawl`, `stop_crawl`, `pause_crawl`, `resume_crawl`, `clear_crawl`, `get_crawl_progress`, `get_desktop_project`
🧑‍🤝‍🧑 Agent sessions (parallel agents)	`session_create`, `session_close`, `session_save`, `session_list`, `session_status`

start_crawl accepts a startUrl plus optional whitelisted overrides (scope, maxDepth, maxUrls, maxConcurrency, maxRps, crawlDelayMs, requestTimeoutMs, respectRobotsTxt, followRedirects, crawlExternal, userAgent, include/excludePatterns) — anything you don't override keeps the desktop user's saved value. Crawls launched via MCP go through the same code path as the UI's Start button, so progress shows up in the desktop app live as the agent drives it. Call clear_crawl first when you want a fresh BFS after a completed crawl with the same seed URL (otherwise the crawler treats the re-start as a resume and exits because every URL is already in the DB).

Several agents at once. Multiple MCP clients can drive one running desktop app safely. Crawl control is a lease: start_crawl returns a crawlId you own, a second start against a busy session fails with crawl-in-progress (or, with onBusy: "queue", waits its turn — or "takeover" to replace it), and stop/pause/resume refuse to touch a crawl owned by another client unless you pass force: true. clear_crawl won't wipe the desktop window's project when it has unsaved work. For full isolation, call session_create to get your own headless session inside the same app — its own database, crawler and worker pool — so each agent crawls its own project without seeing the others; the MCP read tools automatically repoint to it. session_create({ mode: "open", projectPath }) reopens a saved .seoproject to keep working on it (PageSpeed, spelling, exports, re-crawl), and session_save / session_close({ save: true }) persist it — so the data no longer disappears when the session that produced it ends. Sessions are capped and idle ones are auto-closed (saving first if they have a document).

1. Build it once:

npm run build:mcp

This produces apps/mcp-server/dist/index.js.

2. Register it with your MCP client.

Claude Desktop

Edit your Claude Desktop config:

Platform	Path
Windows	`%APPDATA%\Claude\claude_desktop_config.json`
macOS	`~/Library/Application Support/Claude/claude_desktop_config.json`
Linux	`~/.config/Claude/claude_desktop_config.json`

{
  "mcpServers": {
    "freecrawl": {
      "command": "node",
      "args": ["/absolute/path/to/FreeCrawl-SEO-Tool/apps/mcp-server/dist/index.js"]
    }
  }
}

Restart Claude Desktop. The freecrawl server appears under the tool 🔌 icon.

Claude Code (CLI)

claude mcp add freecrawl -- node /absolute/path/to/FreeCrawl-SEO-Tool/apps/mcp-server/dist/index.js

Other MCP clients

Run the binary directly with stdio transport:

node apps/mcp-server/dist/index.js

The server speaks newline-delimited JSON-RPC 2.0 — point any MCP-compatible client at it.

3. Try it. Ask your agent things like:

"Crawl https://example.com with maxDepth 3 and watch the progress." "Show the 10 URLs with the longest response time in my last crawl." "What are the top 5 issue categories with the most affected pages?" "List every URL with a missing meta description." "Pause the running crawl, then resume it once I've checked the first 1000 URLs."

Pointing at a non-default project:

By default the server reads <userData>/projects/default.seoproject (the same file the desktop app uses). Override with the FREECRAWL_PROJECT env var, or call the set_project tool mid-session:

{
  "mcpServers": {
    "freecrawl": {
      "command": "node",
      "args": ["/path/to/apps/mcp-server/dist/index.js"],
      "env": { "FREECRAWL_PROJECT": "/path/to/audit.seoproject" }
    }
  }
}

📋 Prerequisites

For developers / source builds

Component	Minimum	Where
Node.js	22 LTS (24 also OK)	nodejs.org
npm	10+ (ships with Node)	bundled
Git	any recent	git-scm.com

Why no Python / MSBuild / node-gyp? FreeCrawl uses Node 22's built-in node:sqlite instead of better-sqlite3. There are zero native dependencies — npm install never invokes a C++ compiler.

Verify your setup:

node --version    # v22.x.x or v24.x.x
npm --version     # 10+

Runtime requirements (any platform)

Outbound HTTPS access to the sites you crawl. Behind a corporate proxy? Set HTTPS_PROXY=http://your-proxy:port before launch, or enter a proxy URL in Settings → Network — HTTP/HTTPS proxies route through undici's ProxyAgent, and SOCKS5 / SOCKS4 proxies (socks5://…, including the h / 4a remote-DNS variants — handy for routing crawls through Tor / a SSH tunnel) are tunnelled automatically.
TLS root certificates. Node ships with the Mozilla CA bundle. If your antivirus or company proxy performs HTTPS inspection (Kaspersky, ESET, Zscaler, BlueCoat, …), set NODE_EXTRA_CA_CERTS=C:\path\to\corp-ca-bundle.crt — otherwise crawls fail with UNABLE_TO_GET_ISSUER_CERT_LOCALLY.

Disk + memory budget

Resource	Size
`node_modules` after `npm install`	~600 MB
Production Electron build	~150 MB
Peak RAM, 100K-URL crawl	~100 MB
1M-URL crawl	comfortably under 1 GB

📁 Project Structure

FreeCrawl-SEO-Tool/
├── 📄 FreeCrawl-SEO-Tool-Start.bat   # Windows one-click launcher
├── 📄 FreeCrawl-SEO-Tool-Start.sh    # macOS / Linux one-click launcher
├── 📄 CHANGELOG.md                   # versioned release notes
├── 📂 apps/
│   ├── 🪟 desktop/                   # Electron app (main + preload + renderer)
│   ├── ⌨  cli/                       # headless Node CLI
│   └── 🤖 mcp-server/                # MCP server for AI agents
└── 📂 packages/
    ├── 🔗 shared-types/              # IPC + domain types
    ├── 💾 db/                        # ProjectDb (node:sqlite) + migrations
    └── 🕷 core/                      # crawler engine (UI-agnostic)

Dependency graph

graph LR
  A[shared-types] --> B[db]
  B --> C[core]
  C --> D[desktop]
  C --> E[cli]
  B --> F[mcp-server]

📈 Status

Note

Active development — feature-complete for daily SEO audits. All 32 analysis tabs, 150+ issue checks, JavaScript rendering (screenshots, LCP candidate, Mobile Usability), multi-window projects, the link visualiser, every Google integration (Search Console / GA4 / PageSpeed / CrUX), LanguageTool spelling, AI per-URL prompts, SEO Authority providers, Google Sheets + BigQuery export, encrypted projects, the MCP server with live crawl control, and the standalone Log File Analyzer all ship today.

Cross-platform installers ship for Windows (.exe + portable), macOS (.dmg, arm64 + x64), and Linux (.AppImage / .deb / .rpm), with Playwright Chromium bundled so JS rendering works on first launch. The virtualized 1M-row table streams the first row in ~1 s, and long crawls are tuned for Apple Silicon (see docs).

Upcoming: Plugin system, Light theme, Code-signing + auto-update.

🤝 Contributing & Support


🐛 Found a bug?	Open an issue
💡 Have a feature idea?	Start a discussion
📦 Want the prebuilt app?	Download a release
🌐 Project website	freecrawl.net

📜 License

MIT — see LICENSE

_{Built with ❤ for SEO professionals who want a fast, free, open alternative to Screaming Frog.}

README.md Unescape Escape

FreeCrawl SEO Tool

Open-source desktop SEO crawler — a free, cross-platform alternative to Screaming Frog