Sitebulb vs WebPageTest in 2026: Full-site crawler vs single-page performance diagnostics
Sitebulb crawls a whole site for 300+ prioritized SEO hints starting at $18 a month. WebPageTest is free, open source, and tests one page at a time with a filmstrip and full request waterfall that no crawler produces.
Sitebulb
WebPageTest- WebPageTest's public instance is free with no account required; Sitebulb has no permanent free tier, only a 14-day trial on paid plans starting at $18/month.
- Sitebulb crawls an entire site for 300+ prioritized technical SEO hints; WebPageTest tests one URL at a time with filmstrip and waterfall diagnostics rather than crawling for structural issues.
- WebPageTest runs tests through real browser instances across 30-plus global locations; Sitebulb crawls a site directly and has no multi-location testing feature.
- JavaScript rendering is included on every Sitebulb plan including the $18/month Lite tier, with no separate JS crawling charge.
- WebPageTest's No-Code Experiments let you test the impact of a hypothetical change, like removing a third-party script, before touching a codebase; Sitebulb has no equivalent experimentation feature.
- Sitebulb produces customized branded PDF reports on Pro and Cloud plans; WebPageTest has no built-in client-report generation, its output is diagnostic data.
Sitebulb and WebPageTest solve different problems that both happen to fall under technical SEO. Sitebulb crawls an entire site and returns over 300 prioritized hints on broken links, duplicate content, and structural issues, with JavaScript rendering included on every plan from $18 a month. WebPageTest does not crawl a site at all. It runs a single URL through a real browser at one of 30-plus global locations and hands back a frame-by-frame filmstrip, a full request waterfall, and Lighthouse scores, and the public instance is free with no account required. If the question is "what is wrong across this whole site," Sitebulb answers it. If the question is "why is this one page slow," WebPageTest goes deeper than almost anything else available.
The tools at a glance
Sitebulb
Website crawler for technical SEO audits with prioritized hints and visual reporting
Sitebulb crawls a site and converts the results into more than 300 prioritized Hints, each ranked by severity with educational context so a less experienced team member understands the why, not just the what. JavaScript rendering is included on every plan, including the $18/month Lite tier, which several competing crawlers charge extra for or gate behind an enterprise upgrade.
Reporting is where Sitebulb differentiates itself further: Pro and Cloud plans generate branded PDF exports and data visualizations built for handing off to a client, and Cloud scales crawls up to 10 million URLs with scheduled recurring audits and team collaboration built in.
None of that overlaps with what WebPageTest does. Sitebulb has no waterfall view, no filmstrip, and no per-request timing breakdown; it tells you what is structurally wrong across a crawl, not why one specific page is slow to render.
| Feature | Lite $18/month | Pro $42/month | Cloud From $125/month |
|---|---|---|---|
| URLs per audit | 10,000 | 500,000 | Up to 10 million |
| SEO Hints | 100+ | 300+ | 300+ |
| JavaScript crawling | Yes | Yes | Yes |
| Scheduled audits | No | Yes | Yes |
| Customized PDF reports | No | Yes | Yes |
| Free trial | 14 days | 14 days | 14 days |
WebPageTest
The open-source gold standard for deep web performance diagnostics, trusted by engineers at Google, Mozilla, and every serious web team.
WebPageTest runs a single URL through a real Chrome, Firefox, or Edge instance at one of 30-plus global test locations and returns a full request waterfall, showing connection, DNS, SSL, and response timing for every asset on the page, not just a score. The filmstrip view adds a frame-by-frame record of what a user actually sees as the page loads, which is genuinely hard to get from any other free tool.
The core product has been free for over fifteen years, maintained now by Catchpoint after its original creation by AOL engineer Patrick Meenan, and is still the benchmark that commercial performance tools measure themselves against. Every run can include a full Lighthouse audit alongside the waterfall, and No-Code Experiments let you quantify the effect of a hypothetical change, such as removing a third-party script, before involving engineering time.
WebPageTest does not crawl a site or detect structural SEO issues. There is no hint system, no meta tag checking, and no duplicate content detection; the tool exists entirely to diagnose why one page is slow, in more depth than a crawler would ever surface.
| Feature | Free Free | Pro API (Starter) $9.89/month |
|---|---|---|
| On-demand tests | Shared queue | Priority access |
| Global test locations | 30+ | 30+ |
| Filmstrip and video replay | Yes | Yes |
| API access | No | Yes |
| Continuous monitoring | No | Yes |
Head-to-head feature comparison
| Feature | Sitebulb | WebPageTest |
|---|---|---|
| Core function | Full-site technical SEO crawling with 300+ prioritized hints | Deep single-page performance diagnostics through real browser testing |
| Full-site crawling / technical issue detection | Yes, 300+ hints across categories, ranked by severity | No, not a site crawler, tests are run URL by URL |
| Single-URL deep performance diagnostics | No, Sitebulb audits a whole site rather than diagnosing one page load | Yes, this is the core product |
| Real browser testing across global locations | Not applicable, Sitebulb crawls the site directly rather than testing from regional locations | Yes, 30+ locations on real Chrome, Firefox, or Edge instances |
| Filmstrip / full request waterfall | No, data is presented as hints and visualizations, not a waterfall | Yes, filmstrip, video replay, and full request waterfall |
| JavaScript rendering | Yes, included on every plan including Lite | Yes, real browser rendering, not headless emulation |
| Scheduled / continuous monitoring | Yes, scheduled crawls on Pro and Cloud | No on the free tier; Pro API supports programmatic scheduling |
| Branded PDF / custom reporting | Yes, customized PDF reports on Pro and Cloud | No, not documented |
| API access | Not publicly documented | No on the free tier; Yes on Pro API |
| Free tier | No (14-day free trial only) | Yes, public instance is free with no account required |
| Starting paid price | $18/month | $9.89/month for Pro API |
Which should you choose?
SitebulbWebPageTestWebPageTestWebPageTestSitebulbSitebulbThe overlap between these two tools is smaller than the shared "technical SEO" label suggests. Sitebulb produces a prioritized list of what is structurally wrong across a whole site; WebPageTest produces a forensic breakdown of why one page is slow. Neither substitutes for the other, and a team doing serious technical SEO work will likely want both in rotation rather than picking one and dropping the other.
Bottom line
Use WebPageTest for one-off diagnostic work on specific slow pages, since the public instance is free and the waterfall and filmstrip data go deeper than anything a crawler produces. Use Sitebulb's 14-day trial to evaluate its crawl output if the immediate need is a prioritized list of structural technical SEO issues across an entire site, since JavaScript rendering is included from the $18/month Lite plan. Pair the two if the work involves both fixing structural issues and proving a specific page got faster afterward.
Frequently asked questions
Do Sitebulb and WebPageTest solve the same problem?
No, they solve different problems despite both being technical SEO tools. Sitebulb crawls an entire site to surface 300+ prioritized structural issues, while WebPageTest tests one URL at a time and returns deep performance diagnostics like a filmstrip and full request waterfall that a crawler does not produce.
Is WebPageTest really free, unlike Sitebulb?
Yes, the public WebPageTest instance at webpagetest.org is free with no account required, and the paid Pro API at $9.89/month only adds priority queuing and programmatic access. Sitebulb has no permanent free plan, only a 14-day trial on paid tiers starting at $18/month.
Can WebPageTest crawl a whole site the way Sitebulb does?
No, WebPageTest tests one URL at a time and has no crawling or site-wide issue detection built in. Teams that need to audit an entire site for broken links, duplicate content, or redirect chains need a crawler like Sitebulb instead.
Which tool gives deeper data on why a page is slow?
WebPageTest gives significantly deeper performance data, including a frame-by-frame filmstrip and a full request-level waterfall with connection, DNS, and SSL timing. Sitebulb has no performance diagnostics at all; its focus is structural and content-based technical SEO issues.
Does Sitebulb test from multiple global locations like WebPageTest?
No, Sitebulb crawls a site directly rather than running tests from regional locations. WebPageTest runs real browser tests from 30-plus global locations, which is useful for understanding how a page performs for users in different regions.
Which tool should an agency use for client reporting?
Sitebulb is the stronger fit for client-facing reporting, since Pro and Cloud plans generate branded, customized PDF exports built for handing off findings. WebPageTest has no report branding or client-delivery feature; its output is raw diagnostic data meant for a technical audience.