--- title: "Screaming Frog vs BlackSEOAnalyzer: Why I Built My Own Crawler" description: "Screaming Frog is great until you hit a million JS-rendered URLs and your laptop starts begging for mercy. Here's why I stopped fighting the desktop ceiling and built BlackSEOAnalyzer instead." image: "https://cdn.blackseoanalyzer.com/blog-images/screaming-frog-alternative-for-modern-audits.jpg" canonical: "https://www.blackseoanalyzer.com/en/blog/screaming-frog-alternative-for-modern-audits" language: "en" --- # Screaming Frog Alternative for Modern Audits By [Seth Black](https://www.blackseoanalyzer.com/en/about) · Published December 21, 2025 · Updated September 16, 2026 ![Screaming Frog Alternative for Modern Audits](https://cdn.blackseoanalyzer.com/blog-images/screaming-frog-alternative-for-modern-audits.jpg) I like Screaming Frog. Used it for years, paid for licenses, shipped real fixes because of it. I also hit the same three walls enough times that I eventually just built something else. ## Where the Frog starts slipping The first crack shows up around the half-million URL mark. Your laptop fan spins up, memory balloons, and you start playing the “close Chrome and hope” game. You can tune the JVM, point it at a bigger database, and throw an M-series machine at it. It works. Sort of. The second crack is JavaScript rendering. Frog added headless Chrome years ago, and it’s fine for a handful of templates. Turn it on for a million-page SPA and go make dinner. Come back and it’s still chewing. The third crack is the export. You end up with a pile of CSVs and no context. Internal links here, canonicals there, response codes in that folder. Stitching them back into a story takes longer than the crawl did. None of this is Frog’s fault. It’s a JVM desktop app, and there’s only so far you can tune one. The ceiling just got in my way. ## Why I built BlackSEOAnalyzer I wanted a crawler that could get through a big site on the machine I already own without eating all of its memory. I wanted JS rendering that holds up across a whole site, not just a handful of templates. And I wanted the output to look like an audit, not a zip file of homework. I built it to fix the specific things that annoyed me, so the feature list is basically a list of complaints: - No URL cap and no “upgrade your license” popup at 500k pages. - Add `--spa` and every page goes through headless Chrome, so a React or Vue site gets crawled after its JavaScript runs, not as an empty shell. - Every page is written to a local SQLite database as it’s crawled, so memory doesn’t balloon and you can regenerate reports without crawling again. - Every issue carries a severity, and `--aggregate-warnings` rolls them up by issue type with counts and affected URLs. You get a list of fixes, not a list of URLs. - Every crawl is kept. Compare this week’s database against last week’s with a few lines of SQL, and if somebody pushed a change that broke 40k canonicals overnight, you’ll know which deploy did it. If you’re coming from a tool like Lumar and want the same depth without the enterprise contract, [BSA is built as a one-time-license Lumar alternative](https://www.blackseoanalyzer.com/en/blog/lumar-alternative-without-enterprise-bs) with JavaScript rendering included. ## The kind of stuff it actually catches On one site I ran through it last month, BSA flagged a client-side redirect chain that only fired for logged-out users on mobile. Frog rendered the final page and moved on. BSA caught the chain, and the fix was a four-line change in a Next.js middleware file. That’s the kind of surgical output I want from a crawler. A quick query against the same crawl data also turned up a pagination loop where `rel="next"` pointed back to page one after page 47. Small bug, thousands of wasted crawl budget hits, invisible unless you’re looking at the whole graph. If you want to dig into link-level issues without running a full-site crawl first, you can also [extract and validate all links on a single page](https://www.blackseoanalyzer.com/en/blog/how-to-quickly-see-all-links-on-a-webpage) to sanity-check templates before you commit to a full run. ## Should you switch If you audit small brochure sites and you love your current workflow, keep using Frog. Honestly. It’s a great tool, the team ships updates regularly and actually responds to bug reports, which is more than I can say for a lot of software I pay for. If you’re auditing anything over a couple hundred thousand URLs, anything JS-heavy, or anything where the client wants a report instead of a pile of exports and no context, give BSA a shot. The free trial runs 14 days with every feature and no page limit, and it doesn’t ask for a credit card, which I insisted on because I hate that pattern in every other tool I’ve ever signed up for. Go try it at [blackseoanalyzer.com](https://www.blackseoanalyzer.com/free-trial). Break it, email me about what broke, and I’ll probably fix it that week. The upside of building your own tools is that the roadmap is basically whatever broke last Thursday. Mine’s a long list. If you’re shopping for a Screaming Frog replacement, run the same audit in BSA. [Free 14-day trial](https://www.blackseoanalyzer.com/free-trial) — no credit card. -Sethers About the author [Seth Black](https://www.blackseoanalyzer.com/en/about) Seth is a software engineer and engineering leader who builds bseoa, a Rust-based technical SEO crawler with a GUI and CLI. He writes about the crawling, rendering and indexing problems he runs into on real sites. [LinkedIn](https://www.linkedin.com/in/seth-black-tx/) · [GitHub](https://github.com/sethblack) · [YouTube](https://www.youtube.com/@SethBlack) [Back to Blog](https://www.blackseoanalyzer.com/en/blog) ## Discover hundreds of SEO Issues in Seconds Without Monthly Subscriptions Comprehensive technical SEO analysis powered by ML and 16 specialized modules. Optional AI-powered insights from Claude, GPT-4, or Gemini. Get actionable insights in seconds, and never pay monthly fees again. [Download Free Trial](https://www.blackseoanalyzer.com/en/free-trial) I use AI to generate images for my posts and for general editing, updates, and ironically SEO purposes. I used to draw all of the images for my personal blog (taleas) myself, but as the volume of content I produce has increased, I've turned to AI tools to help create visuals that complement my writing. I go out of my way to generate images that look strange, and don't represent real people. 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