Crawl Lab vs Spider-Lens

Crawl Lab is a free web toolbox for analyzing server logs and AI crawler activity. It accepts Apache and Nginx common or combined logs, including compressed.gz files, and reports crawled pages, crawl frequency, wasted crawl budget, and bot errors. The analyzer recognizes GPTBot, OAI-SearchBot, ClaudeBot, PerplexityBot, Google-Extended, Bytespider, Amazonbot, and other crawlers, checking their authenticity against official IP ranges. Processing occurs in the browser, so log files and IP addresses stay on your machine and are not uploaded or stored. No registration is required. Streaming reads allow analysis of several gigabytes or a full month of logs without a server-imposed size limit. Crawl Lab targets technical SEO practitioners concerned with SEO and generative-engine visibility. Its results show what crawlers fetched, not whether pages were indexed or how they rank. An llms.txt generator and AI citation audit are listed as coming soon. The free plan costs nothing, with no paid tier.

Spider-Lens is a free, open-source application for analyzing Apache and Nginx server logs. It monitors traffic, HTTP errors, crawler bots and server performance through a dashboard covering requests, human visits, error rates, HTTP status trends, bot distribution and 12-week patterns. Crawler monitoring detects 16 or more bots and shows crawl budget and crawler volume. Performance reports include Time to First Byte by URL, configurable slow thresholds and CSV or Excel export. A sitemap crawler follows internal links and records titles, H1 headings, word counts, canonicals, robots directives and crawl depth. SMTP alerts and webhooks can report 404 spikes, server errors, missing Googlebot and weekly summaries. The project documents Discord, Slack and an MCP server integration. It runs as a Node.js application or native WordPress plugin, with no Node.js required for the plugin. Node deployment requires Node.js 18+, npm 9+ and log access. The interface lists 16 languages and automatic browser-language detection. Nova uses Gemini when configured.