Page speed scored with Lighthouse,
not YSlow
Pingdom's page speed monitor still grades pages with YSlow, a Yahoo methodology from the late 2000s. Modern web performance is measured by Google Lighthouse. The gap matters when your client asks why their Lighthouse score does not appear in your report.
Also evaluating Oh Dear, UptimeRobot, StatusCake, or Site24x7? See those comparisons, or browse all alternatives.
Pingdom still scores page speed with YSlow
Pingdom's Page Speed Monitoring product page (linked below) describes its grading using YSlow, a methodology released by Yahoo in 2007. Most agencies evaluating Pingdom side-by-side with newer tools are surprised by this, because YSlow scores are not what PageSpeed Insights shows them today.
"Understand your page's overall load time, number of requests, size and how it ranks according to Yslow's performance matrix."
YSlow is a page-speed grading system originally released by Yahoo in 2007. The hosted YSlow API was retired in 2014. The browser extensions were discontinued. The methodology has not been meaningfully updated in over a decade. By contrast, Google Lighthouse was released in 2016 and is the modern industry standard for web performance scoring (Performance, Accessibility, SEO, Best Practices, plus lab Core Web Vitals LCP and CLS, and the TBT proxy for interactivity).
For an agency, the practical difference is what you can show a client. A YSlow letter grade is unrecognisable to most non-developers today. A Lighthouse score is what Google's own PageSpeed Insights returns, what every Chrome DevTools panel surfaces, and what the client likely already knows the score of.
Source: pingdom.com/product/page-speed. Verified .
Quick verdict
Both tools are good at the jobs they were built for. The decision comes down to who you are and what you need to deliver.
Enterprise teams already on SolarWinds, or anyone who needs RUM
Enterprise IT teams whose procurement requires a large, long-established vendor, teams already running on the SolarWinds Observability platform, or anyone who needs Real User Monitoring on a high-traffic site (Pingdom's RUM captures actual visitor sessions, which synthetic checks cannot replicate).
Also a good fit if you need multi-step transaction monitoring, 100+ global probe servers, SMS alerts on every plan, and integrations with PagerDuty / OpsGenie / Splunk On-Call out of the box.
Agencies monitoring client sites
Your monthly client deliverable depends on a recognisable Lighthouse score (the current standard, not a 2007 YSlow grade), day-over-day visual change detection on inner pages, and a branded report that lands in your inbox ready to forward. The AI classifier filters cosmetic noise so the alerts that reach your inbox fire on real breakage, not on a deploy that swapped the hero image.
SiteLetter is shaped and priced for that job. $5/site flat at every portfolio size, no Quantity slider, no separately-billed RUM or Transaction product to unlock the agency feature set.
Where Pingdom does not fit the agency deliverable
Pingdom covers infrastructure monitoring well: uptime, RUM, transactions, global probes. The things below are not listed on Pingdom's published pricing and product pages as of May 2026, and they are the table-stakes of the agency monthly deliverable.
Lighthouse scoring, not a 2007 YSlow grade
Pingdom's page-speed product reports load time, request count, total page size, and a YSlow-style performance grade - a 2007 Yahoo framework whose hosted API was retired in 2014, superseded by Google Lighthouse. There is no Performance, Accessibility, SEO, or Best Practices score in the product, and Core Web Vitals (LCP, INP, CLS) only show up if you buy RUM as a separate subscription. SiteLetter runs Google's current Lighthouse on every monitored page across every client site, daily, and pre-warms DNS, TLS, and CDN caches before each audit so the score is stable enough to ship to a client as a real trend.
Daily screenshot diffs, not single-load filmstrips
Pingdom's "filmstrip" captures one page load in 500-millisecond increments to visualise paint progression - a useful single-session debugging artefact, not a change-detection tool. It does not compare today's render against yesterday's. SiteLetter captures a full-page screenshot of every monitored page on mobile and desktop every day, and runs an AI classifier over every diff big enough to matter. A new hero banner, a cookie notice variant, a rotating ad gets dismissed as cosmetic noise. A genuine content update lands in the next scheduled report. A broken layout - a deploy hiding the cart icon, a CDN config dropping product images, a 404'd stylesheet - is emailed after the next daily scan.
One flat price, not a Quantity slider
Pingdom's Synthetic plan starts at $16.50/mo for 10 uptime checks; the Quantity slider scales the same product up: 100 monitors at ~$136/mo, 200 at ~$265/mo, 300 at ~$386/mo. To match SiteLetter's per-page coverage on a 5-client portfolio you need ~75 monitors (~$136/mo); on a 20-client portfolio, ~300 monitors (~$386/mo). And that is uptime only - Lighthouse equivalents, day-over-day visual diffing, and branded reports are not in that bill. SiteLetter is $5/site flat at every portfolio size, with the full feature set included.
Reports your client opens, not dashboards they have to visit
Pingdom's "shareable reports" and public status pages are URLs your client has to open in a browser to see anything. Pingdom does not publish a scheduled monthly report carrying your agency logo, brand colour, and reply-to address, as of August 2026 per pingdom.com's published reporting documentation. SiteLetter is built around the opposite shape: on the cadence you set the finished report lands in your inbox in your branding, you forward it, and your client reads it with no SiteLetter login screen and no account to create.
Agency-shaped branding, not vendor-shaped
Pingdom's status pages take a logo, brand colours and your own domain. What Pingdom does not publish is a scheduled, per-client branded email report: no per-client reply-to on anything Pingdom sends, and no setting that removes the Pingdom name from a delivered report, as of August 2026 per pingdom.com's published status page and reporting documentation. SiteLetter ships all of that as standard - logo, colour, and reply-to per client, plus an agency-branding toggle that removes "SiteLetter" from the report - on every scheduled report that goes out.
One URL to set up a client, not two Pingdom products and four setup flows
Onboarding a client on Pingdom means two separately-billed products and several setup flows inside them: Synthetic (uptime checks, page speed, and advanced/transaction checks, each defined per URL) and Real User Monitoring, billed on its own pageview ladder. Onboarding the same client on SiteLetter is pasting one URL. The sitemap is auto-fetched, the 15 most important pages are picked, every monitoring service turns on, and the report template is pre-built. One set of alert rules, written once at agency level, covers the lot: every client, every site, and every site you add after.
Feature-by-feature comparison
The full picture, grouped by category. Some of these are SiteLetter wins (per-page services, agency-shaped reports). Some are Pingdom wins (RUM, multi-region probes, channel breadth). The honest answer is "both."
| Feature | SiteLetter | Pingdom |
|---|---|---|
| Pricing model | ||
| Pricing unit | 1 site (up to 15 pages) | Per-check (Synthetic) + per-pageview (RUM), separate products |
| Cheapest commercial plan | $5/site (15 pages monitored, all services) | $16.50/mo annual Synthetic entry tier (10 uptime + 1 advanced + 50 SMS); RUM is a separately-billed product |
| Free trial | 14 days, 1 site | 30 days, full Synthetic + RUM |
| Pricing shape | Linear $5/site at every size, all features included | Quantity slider on Synthetic scales price with check count; RUM scales separately by pageview tier; Enterprise (500K+ pageviews) requires sales contact |
| Per-page services on a client site | ||
| Uptime checking | Homepage every 1 min + 14 subpages every 15 min | 1 check per URL; intervals 1 min and up depending on tier |
| Google Lighthouse audits (Performance / Accessibility / SEO / Best Practices) | Every monitored page, daily, with cache warmup | Not offered (page-speed grading uses YSlow performance matrix) |
| AI visual regression (day-over-day) | Every monitored page, daily, classified | Not offered (filmstrip is during single page load, not day-over-day) |
| Core Web Vitals (LCP, CLS) plus lab interactivity (TBT) | Yes (via Lighthouse, every monitored page) | Available via RUM (separate $16.50/mo subscription), based on real visitor data not lab measurement |
| Broken asset detection | Every monitored page, daily | Not offered |
| Site-level services | ||
| SSL certificate expiry alerts | Yes | Yes |
| Domain expiry alerts | Yes | No |
| Sitemap auto-discovery | Yes (weekly sync) | No (every URL added manually) |
| Public status page | Not available | Yes |
| Multi-step transaction monitoring | No | Yes (Advanced check on Synthetic) |
| Real User Monitoring (RUM) | No | Yes (separate product, $16.50/mo for 100K pageviews and up) |
| Monitoring data retention | 2 years (730 days) for Lighthouse, screenshots, asset checks and reports; uptime incidents retained, raw uptime check samples 7 days | Uptime: shown since check creation (long history); page speed: ~7 days overview, 2 weeks detailed; RUM: 13 months on current plans |
| Reports your clients read | ||
| Scheduled client-facing email report | Yes (weekly, bi-weekly, monthly, quarterly) | Shareable reports + public status pages (dashboards your client visits, not branded scheduled emails) |
| Per-client branding (logo, color, reply-to) | Yes | No |
| Report branding at agency level | Yes (the SiteLetter name is removed from the report, and your agency name is the sender) | No |
| Drag-and-drop report builder | Yes | No |
| Recipients view reports without a login | Yes (a branded email you forward; the recipient needs no account) | Public status pages are accessible without login; scheduled report-side delivery for clients is not in the product |
| Probes, channels, and platform | ||
| Multi-region probes | 3 regions (EU primary + US verifier + AP tiebreaker), monitoring data stored in the EU; screenshots go to OpenAI in the US under SCCs | 100+ servers worldwide |
| Alert channels | Email, Slack | Email, SMS (50 credits on entry), PagerDuty, OpsGenie, Splunk On-Call, Slack, webhooks |
| Public REST API | Not available | Yes (all plans) |
| Native mobile app | No | No (no Pingdom app currently listed in Apple App Store or Google Play) |
Sources: pingdom.com/pricing, page-speed, synthetic-monitoring, real-user-monitoring. Verified .
Cost at your portfolio size
Drag the slider to your client portfolio size. Numbers update live. Pingdom prices come from their published Synthetic Monitoring Quantity tiers.
Pingdom pricing in USD annual rate (Synthetic Monitoring only; Real User Monitoring is a separate Pingdom product, not relevant to per-page uptime). Sourced from the published Quantity tiers at pingdom.com/pricing. The per-page monitors priced here are uptime checks only; Pingdom's page-speed checks are a separate monitor type and are not counted in these figures.
Reading these numbers honestly
Pingdom wins on homepage-only cost. The 10-monitor entry tier at $16.50/mo covers up to 10 client sites of homepage uptime. SiteLetter at that size is $50/mo. For pure-uptime use cases at small portfolios, Pingdom is cheaper.
SiteLetter wins on per-page coverage shape. To match SiteLetter's 15-page coverage, Pingdom needs 15 separate uptime monitors per site. That pushes Pingdom to roughly 5.4x SiteLetter's price at 5 sites, easing to about 3.9x at 20 sites as the Quantity tiers get cheaper per monitor. And Pingdom's per-page service is uptime only: Lighthouse, AI visual regression, and branded client reports are not in the product. SiteLetter at $5/site includes all of that.
Cost at common portfolio sizes
"Matching coverage" assumes one uptime monitor per page (15 monitors per site, the shape required to get per-page visibility on Pingdom). "Homepage only" is one uptime monitor per site.
| Client sites | SiteLetter | Pingdom: matching coverage (15 monitors/site) | Pingdom: homepage only (1 monitor/site) |
|---|---|---|---|
| 5 | $25/mo | $136/mo | $17/mo |
| 10 | $50/mo | $265/mo | $17/mo |
| 20 | $100/mo | $386/mo | $36/mo |
Source: pingdom.com/pricing (Synthetic Monitoring Quantity tiers, annual rate), verified .
Where Pingdom genuinely wins
Pingdom has been around since 2007 and the product depth shows. If you need true Real User Monitoring on a high-traffic site, multi-region synthetic probes from 100+ servers, or you already run on SolarWinds, Pingdom is the better fit. The wins below are real and SiteLetter does not currently match them.
Real User Monitoring is a mature product
Pingdom RUM ($16.50/mo annual for 100,000 pageviews; Enterprise scales to 5M+) captures actual visitor sessions in real browsers, geographic distribution, browser and device breakdowns, and live performance from real traffic. Synthetic monitoring cannot replicate that. SiteLetter does not ship RUM. If you need true visitor-side performance data on high-traffic client sites, Pingdom is the better tool today.
100+ global probe servers (vs SiteLetter's 3)
Pingdom probes from 100+ servers worldwide (their own wording) and has done so for years. Useful for catching regional outages, CDN edge issues, and BGP routing problems specific to a part of the world. SiteLetter runs a 3-region triangulation (EU primary + US verifier + AP tiebreaker). Monitoring data is stored in the EU. Screenshots go to OpenAI in the US for visual change classification, under EU Standard Contractual Clauses. That is enough to catch regional outages and suppress false positives, but at lower geographic granularity than 100+ vantage points.
Multi-step transaction monitoring
Pingdom's transaction monitoring lets you script a multi-step flow (sign-in, add-to-cart, checkout) and alert when any step fails. Useful for ecommerce checkout flows or login funnels. SiteLetter monitors pages individually but does not script multi-step user journeys.
30-day free trial
Pingdom's free trial is 30 days and covers both Synthetics and RUM. SiteLetter's trial is 14 days and covers one site. If you want a longer evaluation window with the full product surface, Pingdom's trial is more generous.
Public REST API, SMS alerts, integrations breadth
Pingdom ships a public REST API on all plans, SMS alert credits in the Synthetic base subscription (50 SMS on entry), and native integrations with PagerDuty, OpsGenie, Splunk On-Call, and Slack. SiteLetter has email and Slack alerts today; the public API is on the post-launch roadmap, not live yet.
Backed by SolarWinds
Pingdom has been part of SolarWinds since 2014, which means it is not going to disappear. Enterprise procurement teams often need vendor-continuity assurance that an independent product cannot match. If your buyer requires a large, long-established supplier with a track record measured in decades, that is a real win for Pingdom.
For enterprise IT teams, infrastructure operators with RUM requirements, and anyone whose buyer requires a SolarWinds-backed vendor, Pingdom remains the better tool today. I say that because I mean it.
When to pick which
Three honest scenarios.
Agencies, any size
From your first client to your fiftieth. Lighthouse on every monitored page (the score your client actually recognises), AI visual regression, branded reports, and the recipient flow are designed for the agency job: making monitoring a deliverable clients can see. SiteLetter is one tool, $5/site, with the full agency feature set in the base price.
Enterprise ops with RUM needs
Infrastructure teams running high-traffic production sites where Real User Monitoring (actual visitor sessions, geography, device breakdown) is part of the requirement. Pingdom's RUM is mature and operates at enterprise pageview scale; SiteLetter does not ship RUM.
Already on the SolarWinds platform
Teams running SolarWinds Observability, APM, or Log Management already. Pingdom integrates into that single-pane-of-glass and procurement is one renewal. Standalone tools (including SiteLetter) add another vendor; for some buyers that is a non-starter.
SiteLetter vs Pingdom: FAQ
Yes. Pingdom's own page-speed product page (pingdom.com/product/page-speed/) states the product reports how each page "ranks according to Yslow's performance matrix." YSlow is a Yahoo project originally released in 2007; the hosted YSlow API was retired in 2014, the browser extension was discontinued, and the methodology has not been meaningfully updated in a decade. Google Lighthouse is the modern industry standard for web performance scoring (Performance, Accessibility, SEO, Best Practices, plus Core Web Vitals: LCP, INP, CLS). SiteLetter runs full Lighthouse audits on every monitored page daily, with DNS/TLS/CDN cache warmup so scores are stable enough to show your client as a real trend.
No. Pingdom's page-speed monitor returns load time, request count, size, a YSlow-style grade, and a waterfall breakdown of resources. It does not produce Lighthouse scores for Performance, Accessibility, SEO, or Best Practices, and it does not report Core Web Vitals. If your client deliverable depends on a recognisable Lighthouse score, Pingdom does not produce one.
No. Pingdom's "Filmstrip" feature captures screenshots every 500 milliseconds during a single page load (visualising how quickly the page paints), but it does not screenshot pages once a day and compare them to yesterday's screenshots to detect visual changes. There is no day-over-day visual regression in the product. SiteLetter takes a daily screenshot of every monitored page, diffs it against the previous day, and uses AI to classify each diff as noise (rotating banners), intentional updates (logged in the weekly report), or real breakage (missing images, layout collapse, emailed after that day's check).
Pingdom offers "shareable reports" and public status pages, which are dashboards your client visits. It does not ship a scheduled, per-client branded email report with your agency logo, brand color, custom reply-to address. SiteLetter is built around exactly that flow: weekly, bi-weekly, monthly, or quarterly reports, per-client branding, and an optional agency-branding toggle that removes the SiteLetter name from the report body and the sender display name.
It depends on what shape of monitoring you need. Pingdom wins on homepage-only cost at small scale: the 10-monitor Synthetic entry tier is $16.50/mo annual, covering up to 10 client sites of homepage uptime; SiteLetter at that size is $50/mo. For matching SiteLetter's 15-page-per-site coverage, Pingdom needs 15 uptime monitors per site, which pushes them up the Quantity tier ladder: 5 sites = 75 monitors (Pingdom 100-monitor tier at $136/mo, 5.4x SiteLetter at $25), 10 sites = 150 monitors (Pingdom 200-monitor tier at $265/mo, 5.3x), 20 sites = 300 monitors (Pingdom 300-monitor tier at $386/mo, 3.9x). And even at the matched price, Pingdom's per-page service is uptime only; Lighthouse, AI visual regression, and branded client reports are not in the product at any tier. SiteLetter at $5/site includes all of that.
Pingdom's Real User Monitoring is a mature product: it captures actual visitor sessions from real browsers at scale, which synthetic checks cannot replicate. It also has 100+ global probe locations (vs SiteLetter's 3-region triangulation: EU primary + US verifier + AP tiebreaker, monitoring data stored in the EU; screenshots go to OpenAI in the US under SCCs), multi-step transaction monitoring with custom flows, an established public REST API, SMS alerts on every tier, integrations with PagerDuty, OpsGenie, Splunk On-Call, Slack, and the broader SolarWinds Observability stack. The free trial is 30 days vs SiteLetter's 14. If you need RUM on high-traffic sites, 100+ vantage points for geographic diversity, or you already run on SolarWinds, Pingdom is the better fit.
Google Lighthouse on every monitored page daily with DNS/TLS/CDN cache warmup (Pingdom's Page Speed Monitoring product page describes its grading using YSlow, the late-2000s methodology that predates Lighthouse). AI day-over-day visual regression that classifies each diff big enough to matter as noise / intentional / breakage (Pingdom's filmstrip screenshots a single page load to show paint progression; it does not compare a page against yesterday's render). Branded scheduled per-client email reports with per-client logo, brand color, reply-to (Pingdom email is incident alerts, not scheduled per-client deliverables). Sitemap auto-discovery: add a domain, SiteLetter picks the 15 most important pages and every monitoring service turns on for them (Pingdom is per-check manual definition). $5/site flat for up to 15 pages, every service, with your branding on every report.
Tenure cuts both ways. Pingdom has been around since 2007 and was acquired by SolarWinds in 2014. That brings stability (it is not going anywhere) and a robust legacy product. The trade-off agencies often cite: Pingdom's Page Speed Monitoring product page still describes its grading using YSlow (per pingdom.com/product/page-speed/), the late-2000s methodology that predates Google Lighthouse. If you want a stable enterprise vendor backed by an established enterprise vendor (SolarWinds), that is a real win for Pingdom. If you want modern Google Lighthouse on every monitored page, AI visual classification, and branded client reports, SiteLetter is the better fit.
Yes, and the SiteLetter setup is shorter than the original Pingdom one. Each SiteLetter site covers up to 15 pages automatically (sitemap-discovered and ranked by depth, sitemap priority, and recency), so a 100-check Pingdom Synthetic setup typically collapses into 7-10 SiteLetter sites. That figure assumes those checks are extra pages of domains you already cover: the collapse is per domain, not per check. A hundred checks sitting on a hundred separate client homepages stays a hundred SiteLetter sites. Add each unique site once and SiteLetter handles the rest: page selection, every monitoring service enabled, weekly and monthly client report templates pre-built. Alert rules are agency-level: define what should reach you for uptime, SSL and domain expiry, Lighthouse scores, visual changes, and broken assets once, and every site inherits it, including the ones you migrate last. The 14-day free trial includes one site so you can validate the full experience on one client site before bringing the rest over.
Still have questions? Contact us
Comparison based on publicly available Pingdom pricing and product page documentation, last verified . Pingdom is a registered trademark of SolarWinds Worldwide, LLC, used here for identification and comparison purposes only. SiteLetter is independent and not affiliated with, sponsored by, or endorsed by Pingdom or SolarWinds. For the most current Pingdom pricing and feature information, see pingdom.com.
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SiteLetter is the kind of tool you forget you're using, until your client thanks you for the report you didn't write.
- ✓ 2-minute setup. Add a URL. SiteLetter auto-discovers pages, starts monitoring, schedules reports. You pick your alert rules and confirm each client address once.
- ✓ No scripts to install. SiteLetter monitors from the outside, like a real visitor.
- ✓ Cancel anytime. No credit card to start, no contract.