Performance intelligence
Your Client's Homepage Was 1.2MB. Now It's 6.3MB. Nobody Noticed.
Three plugin updates. A gallery redesign. An unoptimised hero image. Each change adds a few hundred kilobytes — and nobody's watching the total. Sitewatch tracks the total download weight of every monitored page on every check. When a page crosses 5MB or a single asset crosses 2MB, a medium-severity incident is created automatically.
- Total page weight tracked on every full-page check
- Medium-severity incident at 5MB page or 2MB single asset — no manual thresholds to tune
- Portfolio-wide visibility — catch bloat across all client sites
Page weight exceeded
Total page weight
- PAGE_WEIGHT_EXCEEDED: 6.3MB total (limit: 5MB)2:00 PM
- hero-background-2x.jpg — 2.8MB (single asset limit: 2MB)2:00 PM
- 147 resources loaded — resource count elevated2:00 PM
- All scripts and stylesheets loading normally2:00 PM
01The monitoring gap
Most tools don't track what your site weighs
| Scenario | Uptime monitoring tools | Sitewatch |
|---|---|---|
| Total page weight tracking | Not monitored | Tracked on every check |
| Per-asset size checks | Not monitored | Content-Length per asset |
| Alerting on weight bloat | No | Medium-severity incident at 5MB / 2MB |
| Resource count detection | Not monitored | Low-severity incident at 100+ resources |
| Portfolio-wide weight visibility | No | Every site on every check |
| Automatic, no manual audits | Requires manual Lighthouse or DevTools | Continuous — no action required |
Total page weight tracking
- Uptime monitoring tools:
- Not monitored
- Sitewatch:
- Tracked on every check
Per-asset size checks
- Uptime monitoring tools:
- Not monitored
- Sitewatch:
- Content-Length per asset
Alerting on weight bloat
- Uptime monitoring tools:
- No
- Sitewatch:
- Medium-severity incident at 5MB / 2MB
Resource count detection
- Uptime monitoring tools:
- Not monitored
- Sitewatch:
- Low-severity incident at 100+ resources
Portfolio-wide weight visibility
- Uptime monitoring tools:
- No
- Sitewatch:
- Every site on every check
Automatic, no manual audits
- Uptime monitoring tools:
- Requires manual Lighthouse or DevTools
- Sitewatch:
- Continuous — no action required
02Why it matters
Page weight creep is invisible — until your clients notice.
Mobile abandonment starts here
Page weight is the single strongest predictor of mobile abandonment. Every megabyte beyond the first significantly increases bounce rate on mobile connections. Your clients' visitors are on phones — a 6MB homepage is not acceptable.
CMS plugins are the culprit
WordPress and Shopify sites are especially vulnerable. Every plugin adds scripts, stylesheets, and sometimes images. Three months after launch, a page that was optimised at 800KB might be 4MB without a single developer touching it.
Weight grows invisibly
Nobody audits page weight after launch. It climbs through content updates, unoptimised image uploads, and plugin additions. By the time a client says "the site feels slow," the damage has been accumulating for months.
Portfolio-scale detection
Agencies managing 50 client sites cannot open DevTools on each one weekly. Sitewatch tracks page weight automatically across your entire portfolio and fires incidents when any site crosses the threshold.
Proactive, not reactive
Sitewatch doesn't wait for a client complaint or a Lighthouse audit. Weight is tracked on every check cycle. A site that goes from 2MB to 5MB over three months triggers a medium-severity incident the moment it crosses the threshold.
Combined with resource count
Page weight and resource count (total HTTP requests) paint the complete front-end health picture. A 6MB page with 200 resources has two separate problems: download cost and request overhead. Sitewatch tracks both.
03Under the hood
How page weight monitoring works
- 01
Fetch the page
Sitewatch fetches your monitored page over HTTP and parses the HTML to identify every linked asset — scripts, stylesheets, images, fonts, and other resources.
- 02
Measure with Content-Length
Each file is checked and its size recorded, without downloading the whole thing — so the measurement is accurate and costs your server almost nothing.
- 03
Total and per-asset thresholds
Sitewatch sums all asset weights and compares against the 5MB page threshold. Individual assets are checked against the 2MB single-asset limit. Either breach triggers an incident.
- 04
Medium-severity incident
When a threshold is exceeded, a PAGE_WEIGHT_EXCEEDED incident is created at medium severity. Your team is alerted with the total weight, heaviest assets, and the threshold crossed.
04What you get
Outcomes, not a feature list.
Catch the upload that made the page four times heavier.
Page weight creeps up one uploaded image at a time, and nobody notices until a client on mobile complains that the site feels slow. Sitewatch measures the full size of every page on each check and flags the jump that caused it.
5MB
Total page weight threshold
2MB
Single asset threshold
Every check
Monitoring frequency
You haven't audited your clients' page weight in months. Sitewatch already has.
Free plan. No credit card. 2-minute setup.
05FAQ
Frequently asked questions
Sitewatch fetches your page, parses the HTML to identify all linked assets, then checks each asset's reported size without downloading it. Total page weight is the sum of every file on the page, including the HTML body. This approach is efficient and accurate without downloading every asset in full.
A PAGE_WEIGHT_EXCEEDED incident is created when total page weight exceeds 5MB or when any single asset exceeds 2MB. Both fire at medium severity. The 5MB total threshold aligns with the point where mobile performance visibly degrades across most real-world connections.
They serve different purposes. Lighthouse and PageSpeed measure performance at a point in time and require manual runs. Sitewatch monitors weight continuously and alerts when thresholds are crossed. Use both: Lighthouse for one-time audits and Sitewatch for ongoing detection of weight creep.
All assets referenced in the page HTML — scripts, stylesheets, images, fonts, and other resources. The HTML document body itself is also included. Third-party assets are included in the total unless they lack a Content-Length header.
Yes. Page weight monitoring is included on all plans — Free, Starter, and Pro. No configuration required.
06Explore more