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. That is easy to miss when comparing tools side by side, because a YSlow grade is not what PageSpeed Insights returns 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 not a number the client can look up anywhere. 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; a synthetic check runs from a probe machine and carries none of them).
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 white-label report that lands in your inbox ready to forward. The AI classifier filters cosmetic noise, so what lands in the dashboard and in that report is real breakage, not a deploy that swapped the hero image.
SiteLetter is shaped and priced for that job. $4.80/site a month with every monitor on, at every portfolio size, no Quantity slider, and no separately-billed RUM or Transaction product.
What the monthly client report needs beyond uptime and RUM
Pingdom covers infrastructure monitoring well: uptime, RUM, transactions, global probes. The things below are what SiteLetter puts in the monthly client report, and as of August 31, 2026 they are not listed on Pingdom's published pricing and product pages.
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 flagged in the dashboard on the next daily scan and called out in that report.
Priced per site at every portfolio size, 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. On uptime the entry rung already carries a small agency: SiteLetter probes one page per site, the homepage, so a 5-client portfolio is 5 checks and a 20-client portfolio is 20, a rung or two up that slider. Uptime is not where the two tools part company. Lighthouse equivalents, day-over-day visual diffing, and branded reports are not in that bill at any check count. SiteLetter is $4.80/site a month with every monitor on, at every portfolio size, and the white-label report comes with every site at no separate rate.
A report that arrives, not a dashboard 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 white-label report lands in your inbox, you forward it, and it opens with no SiteLetter login screen and no account to create.
White-label per client, 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 - white-label reports with 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 monitor 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 |
| Every monitor on | $4.80/site a month (15 pages monitored); less per site if it runs fewer of them | Cheapest commercial plan: $16.50/mo annual Synthetic entry tier (10 uptime + 1 advanced + 50 SMS); RUM is a separately-billed product |
| Free start | 14 days on 1 site, no card | 30 days, full Synthetic + RUM |
| Pricing shape | Per site, the same rate table at every size: $4.80/site a month with every monitor on | 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 from the EU, confirmed from a second region on failure; every monitored page reached daily by the scan | 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 280 days | Uptime: shown since check creation (long history); page speed: ~7 days overview, 2 weeks detailed; RUM: 13 months on current plans |
| Client-facing reports | ||
| 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: white-label, with the SiteLetter name removed from the report and your agency name as the sender | No |
| Drag-and-drop report builder | Yes | No |
| Recipients view reports without a login | Yes - the white-label report renders inside the email, and every report carries a public link that opens without an 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 .
Which job are you buying for?
Comparing monitor counts flatters whoever wrote the comparison. These are the two questions that actually decide it, at 10 client sites.
For uptime alone, Pingdom is a complete answer
Pingdom's entry Synthetic tier covers ten uptime monitors, which is ten client homepages, and their probe network is far larger than SiteLetter's. If uptime with wide geographic spread is the job, they are a serious answer at a modest price.
SiteLetter can be bought that way too, since uptime is a line item you can switch on without the rest. But uptime alone is not the job this page is about, and pretending otherwise would mean pricing around a comparison you can run yourself in a minute.
Lighthouse, visual change detection, a branded report
Pingdom's page-speed check uses YSlow methodology rather than Lighthouse, so the four scores a client's own PageSpeed run shows are not what you would be reporting. There is no day-over-day visual change detection and no scheduled branded per-client report at any tier.
10 client sites with every monitor on, covering up to 150 monitored pages. Prepaid, nothing recurring.
Pingdom figures are the ones that vendor publishes, in the currency they publish them. 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. A synthetic check runs from a probe machine on a schedule, so it carries none of 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 starts you with 14 days of full monitoring on 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, and no public API today.
Backed by SolarWinds
Pingdom has been part of SolarWinds since 2014, which means it is not going to disappear. If your buyer requires a large, long-established supplier with a track record measured in decades, that is a real win for Pingdom.
When to pick which
Three honest scenarios.
Agencies with a portfolio of client sites
Many client sites, on any platform. Lighthouse on every monitored page (Google's own score, under its own name), AI visual regression, white-label reports, and the recipient flow are designed for the agency job: making monitoring a deliverable clients can see. SiteLetter is one tool, $4.80/site a month with every monitor on, with reports and branding included with every site, at no separate rate.
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 last good capture, normally the previous day's, and uses AI to classify each change big enough to matter as noise (rotating banners), intentional updates (logged in the weekly report), or real breakage (missing images, layout collapse, flagged in the dashboard and called out in the report you forward).
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: white-label reports on a weekly, bi-weekly, monthly, or quarterly schedule, with 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 which of two questions you are asking. If homepage uptime is all you need, Pingdom's 10-monitor Synthetic entry tier is $16.50/mo annual and covers 10 client homepages from their probe network, and that is a fair answer to that question. If you want Lighthouse on every monitored page, day-over-day visual change detection and a branded client report, none of those is in the Pingdom product at any tier, so there is no Pingdom plan to price against. SiteLetter at 10 client sites with every monitor on is $48.00/month, covering 150 monitored pages.
Pingdom's Real User Monitoring is a mature product: it captures actual visitor sessions from real browsers at scale, and a synthetic check, running from a probe machine on a schedule, carries none of them. 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. Their free trial is 30 days and covers both products; SiteLetter starts you with 14 days of full monitoring on one site instead, with no card. 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). White-label 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 monitor turns on for them (Pingdom is per-check manual definition). $4.80/site a month with every monitor on, for up to 15 pages, 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 white-label 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 packs into 7 SiteLetter sites when every site is filled to the 15-page cap, and more than that as the same pages spread across more domains. That arithmetic 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 monitor switched on, 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, and broken assets once, and every site inherits it, including the ones you migrate last. New accounts get 14 days of full monitoring on one site with no card, so you can validate the full experience on one client site before bringing the rest over.
Still have questions? Get in touch.
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.
You set up care-plan reporting once.
After that it runs without you.
SiteLetter is the kind of tool you forget you're using, until your client thanks you for the report you didn't write.
- ✓ Just add a domain. SiteLetter auto-discovers pages, starts monitoring, schedules reports. You pick your alert rules and who gets each report.
- ✓ No scripts to install. SiteLetter monitors from the outside, like a real visitor.
- ✓ Nothing recurring. No subscription, no contract. You buy credits when you want them and each site spends its own.