Calibre vs ContentKing in 2026: Performance monitoring vs 24/7 technical SEO health monitoring
One is laser-focused on Core Web Vitals from RUM, synthetic tests, and Google CrUX, priced openly from $75 a month. The other crawls your entire site around the clock for broken redirects and canonical changes, but only sells through a sales call.
Calibre
ContentKing- Calibre publishes transparent pricing from $75/month. ContentKing (now Conductor Monitoring) requires a sales conversation for every tier, including the entry-level Essentials plan.
- Calibre's Starter plan is capped at 5,000 RUM sessions per month, tight for any site with real traffic. ContentKing doesn't sell by session count; it monitors by page volume, up to 100,000 pages on Essentials.
- ContentKing keeps 60 months of snapshot history for every monitored page. Calibre's RUM data retention tops out at 2 years on the Company plan.
- Calibre unifies RUM, synthetic testing, and Google CrUX field data in one dashboard. ContentKing's core strength is continuous crawling for structural SEO issues, not RUM.
- ContentKing's Enterprise tier adds log file analysis covering AI crawlers like GPTBot and ClaudeBot. Calibre has no crawler log analysis of any kind.
- Calibre's Automation API and CLI are included on every tier, even Starter. ContentKing's Data API is locked to Enterprise only.
- ContentKing ranks detected issues by business impact automatically. Calibre's dashboard shows performance budgets and trends but does not rank issues by revenue impact.
Calibre and ContentKing get compared because both promise to catch problems before they cost you traffic, but they are watching for different things. Calibre is a performance specialist: real user monitoring, synthetic tests, and Google CrUX field data, unified in one dashboard with pricing you can see on the website. ContentKing, now sold as Conductor Monitoring after Conductor's acquisition of the product, crawls your whole site continuously and flags structural issues, broken redirects, changed canonicals, missing meta tags, the moment they happen, but you will not find a price anywhere without talking to sales. The right pick depends on whether the problem you are solving is page speed or full-site technical health.
The tools at a glance
Calibre
Web performance monitoring platform that unifies real user monitoring, Google CrUX data, and synthetic page speed tests for teams serious about site speed.
Calibre's entire premise is that performance teams should not have to reconcile exports from three separate tools to answer one question: is the site actually fast for real users. It combines real user monitoring captured via a lightweight JS snippet, scheduled synthetic tests, and Google's own CrUX field data in a single dashboard with a consistent date range and filter set across all three.
The Automation API and CLI are the feature that pulls development teams in specifically. Performance checks can be triggered from CI/CD pipelines, and builds can fail automatically when a configured performance budget is exceeded, all without custom webhook infrastructure. It is the kind of tooling that treats performance as a gate in the deployment process, not a monthly report someone reads after the fact.
The friction shows up in the pricing ladder. The Starter plan's 5,000 monthly RUM sessions get eaten quickly by any site with meaningful traffic, and the jump from Team at $150/month to Company at $1,500/month leaves nothing in between for a growing team that has outgrown Starter but is nowhere near enterprise scale.
| Feature | Starter $75/month | Team $150/month | Company $1,500/month |
|---|---|---|---|
| Real User sessions per month | 5,000 | 10,000 | 1,000,000 |
| Synthetic tests per month | 5,000 | 15,000 | 50,000 |
| Google CrUX data | Yes | Yes | Yes |
| Team seats | 3 | 10 | 50 |
| API and CLI access | Yes | Yes | Yes |
| RUM data retention | 90 days | 1 year | 2 years |
ContentKing
24/7 website monitoring that catches AEO and SEO technical issues before they cost you traffic
ContentKing was one of the first tools to move technical SEO auditing from weekly crawls to continuous monitoring, and that model survived its acquisition by Conductor. The product now runs as Conductor Monitoring, but the core mechanic is unchanged: your site is crawled around the clock, so a broken redirect, a dropped canonical, or a changed meta robots directive gets flagged the moment it happens rather than at the next scheduled audit.
Two things separate it from a standard crawler. Every detected issue is automatically ranked by business impact, weighing factors like the traffic value of the affected page, so teams work the highest-ROI fix first instead of triaging a flat list manually. And the platform keeps 60 months of snapshot history per site, useful for root-cause tracing, compliance evidence, and correlating technical changes with traffic over long time horizons, well beyond the 30-to-90-day window most competitors offer.
The Enterprise tier adds log file analysis that now includes AI crawler traffic from GPTBot, ClaudeBot, and PerplexityBot, showing which pages those bots actually reach. None of this comes with a visible price tag, though: Essentials, Growth, and Enterprise all require a sales conversation, and several features, including that log file analysis and the Data API, are locked to the top tier specifically.
| Feature | Essentials Contact for pricing | Growth Contact for pricing | Enterprise Contact for pricing |
|---|---|---|---|
| Pages monitored 24/7 | Up to 100,000 | Up to 500,000 | Custom |
| Websites tracked | 3 | 5 | 10+ |
| Core Web Vitals | No | Yes | Yes |
| Log file analysis (AI crawlers) | No | No | Yes |
| Data API | No | No | Yes |
| SSO | No | Yes | Yes |
Head-to-head feature comparison
| Feature | Calibre | ContentKing |
|---|---|---|
| Real user monitoring (RUM) | Yes | No |
| Synthetic performance testing | Yes | No |
| Google CrUX field data | Yes | No (Core Web Vitals tracked via continuous crawl, not CrUX field data) |
| 24/7 continuous site crawling | No (scheduled synthetic tests, not continuous full-site crawling) | Yes |
| Broken redirect / canonical change detection | No (not a crawl-based SEO monitoring tool) | Yes |
| Issue prioritization by business impact | No | Yes |
| Log file analysis (AI crawler tracking) | No | Enterprise tier only |
| Snapshot history retention | Up to 2 years (Company plan) | 60 months |
| API access | Yes (every tier, including Starter) | Enterprise tier only (Data API) |
| CI/CD integration (CLI) | Yes (Automation API and CLI) | No (MCP server availability varies; confirm scope with sales) |
| SSO | Not documented | Growth and Enterprise |
| Published self-serve pricing | Yes ($75/mo Starter published openly) | No (contact for pricing on every tier) |
| Starting price | $75/month | Contact for pricing |
Which should you choose?
CalibreContentKingCalibreContentKingCalibreContentKingContentKingCalibreCalibre and ContentKing are not really solving the same problem. Calibre is a performance-metrics specialist: RUM, synthetic tests, and CrUX, with an API and CLI included from the cheapest tier, aimed at teams treating speed as an engineering discipline. ContentKing is a broader technical SEO health monitor, watching for structural breakage across a whole site around the clock, with pricing that only makes sense once you have talked to sales. If Core Web Vitals data is the actual requirement, Calibre gets there faster and cheaper. If the requirement is catching a broken canonical or a dropped noindex tag within hours on a large, frequently changing site, ContentKing is built for exactly that.
Bottom line
Start with Calibre at $75/month if Core Web Vitals and RUM/synthetic/CrUX data are the actual problem you're solving; the pricing is public and the Automation API works from the cheapest tier. Book a ContentKing demo only if you are running a large, frequently changing site where a broken redirect or a dropped canonical needs to be caught within hours rather than days. Budget for a sales process either way if AI crawler log data matters, that is locked to ContentKing's Enterprise tier.
Frequently asked questions
Is Calibre a good substitute for ContentKing's 24/7 site monitoring?
Not directly. Calibre monitors performance data, RUM sessions, synthetic tests, and Google CrUX field data, but it does not crawl your entire site continuously to catch broken redirects, changed canonicals, or missing meta tags, which is ContentKing's core function. If broad technical SEO health monitoring is the goal, ContentKing (now sold as Conductor Monitoring) covers that ground; Calibre stays focused on performance specifically.
Why doesn't ContentKing publish its pricing?
ContentKing has no published pricing on any of its three tiers, Essentials, Growth, or Enterprise all require contacting sales since the Conductor acquisition folded it into an enterprise-first go-to-market. Calibre, by contrast, lists Starter at $75/month, Team at $150/month, and Company at $1,500/month directly on its site.
Does Calibre track AI crawlers like GPTBot or ClaudeBot?
No, Calibre has no log file analysis or crawler tracking of any kind; its three data sources are real user sessions, synthetic tests, and Google CrUX. ContentKing added AI crawler log analysis at its Enterprise tier, letting you see how often GPTBot, ClaudeBot, and other AI indexers visit your pages, but that feature is locked well above Calibre's price range.
How many months of history do Calibre and ContentKing keep?
ContentKing keeps 60 months, five years, of snapshot history on every monitored page, which is unusually deep for this category. Calibre's RUM data retention tops out at 2 years on the Company plan, with the Starter plan limited to 90 days, so if long-range historical diagnosis or compliance evidence is the priority, ContentKing's retention window is considerably longer.
Can Calibre or ContentKing enforce performance budgets in a CI/CD pipeline?
Calibre is built for this: its Automation API and CLI are included on every tier including Starter, letting teams trigger tests from CI/CD and fail builds when performance budgets are exceeded. ContentKing is a continuous monitoring platform rather than a CI/CD tool; its Data API, Enterprise only, is designed for pulling monitoring data into other systems, not for gating deploys on performance thresholds.
Is ContentKing still called ContentKing?
The contentkingapp.com domain and brand still exist, but the product now operates as Conductor Monitoring after Conductor's acquisition of ContentKing, positioned as the technical health layer inside Conductor's broader AEO and SEO suite rather than as a standalone tool.