UptimeRobot says it's up.
Prove you're keeping it that way.
UptimeRobot is a great uptime monitor: it tells you the moment a client site goes down. What it does not do is prove, month after month, that you are keeping the site fast, unbroken, and looked after. SiteLetter adds Lighthouse on every page, daily visual checks across all 15 pages, and a branded report in your inbox ready to forward - the deliverable UptimeRobot was never built to produce.
Also evaluating Oh Dear or StatusCake? See those comparisons, or browse all alternatives.
Uptime is the floor, not the deliverable
Most agencies reach for UptimeRobot to know the moment a client site goes down. That is worth having, and its free tier allows client use per their published terms as of June 19, 2026, so it is a fine place to start. But "the homepage was up" is not what a client pays a retainer for. What they pay for is proof the site is fast, unbroken, and looked after - and that proof is a different product.
Stay on UptimeRobot
If your client deliverable starts and ends at "the homepage is up," UptimeRobot is a solid pick. The free tier covers basic uptime at zero cost and is cleared for client use per their published terms as of June 19, 2026; paid tiers from EUR 9/mo billed annually add 60-second checks, more monitors, and full status pages. You keep the product you already know.
See UptimeRobot pricing →Switch to SiteLetter
SiteLetter at $5/site covers what most agencies actually owe their clients each month: uptime, SSL, Lighthouse on every monitored page, visual regression, and a branded weekly or monthly email report. One tool, one bill, no stack to assemble.
Start free 14-day trial →Quick verdict
Both tools are good. The decision comes down to who you are and what you need to deliver.
Personal sites, infrastructure, or pure-uptime use cases at scale
Hobby sites, open source projects, or anyone monitoring their own infrastructure. Also: ops teams who need ping, TCP/UDP port, DNS, cron heartbeat monitors, and far more probe vantage points, with SMS, voice, or PagerDuty alerts. UptimeRobot ships those well today; SiteLetter does not ship most of them at all.
Per UptimeRobot's published terms as of June 19, 2026, the free tier allows commercial and client use, so for plain uptime on a handful of sites it is hard to beat at zero cost.
Agencies monitoring client sites
Your monthly client deliverable is more than "the homepage was up." When a deploy shifts the contact form behind a hero image, a product photo starts 404ing, or the pricing page's Lighthouse drops from 88 to 41, you want to know before the client does. SiteLetter monitors that across every page on every site, settled in a single billing line. Pick what is worth an alert once, at agency level, and every client site inherits it.
$5/site covers every monitored page across every service, plus a branded weekly or monthly client email - the report the recipient opens without logging into anything.
"Monitor anything! Uptime, SSL, ports, cron, and more in real time."
"Website monitoring for agencies, delivered by email."
What UptimeRobot does not do (that agencies need)
UptimeRobot is excellent at what it was built for: uptime, SSL, status pages, ping, ports, crons. The gaps below are a mix: some are capabilities their published feature documentation does not list at any tier, including their quote-only Enterprise plan, as of the verification date below; others follow from metering by monitor rather than by site. All of them are built into SiteLetter at every tier, because the agency deliverable depends on them.
Lighthouse scoring UptimeRobot does not ship at any tier
UptimeRobot's monitor catalogue is uptime, SSL, port, ping, DNS, and cron heartbeat. Performance scoring is not in any of them, at any rung of their published ladder. SiteLetter runs Google Lighthouse (Performance, Accessibility, SEO, Best Practices) on every monitored page across every client site, daily, and pre-warms DNS/TLS/CDN caches before each audit so the score is stable enough to ship to a client as a trend. Cold-cache Lighthouse moves run-to-run on an unchanged page, which is what makes most third-party Lighthouse data unusable for a client report.
Daily screenshots and AI-classified diffs
UptimeRobot publishes a free website change detection tool that screenshots a page hourly and emails a before/after when it spots a difference, but it sits outside the monitoring plans, is not one of the monitor types on their website-monitoring page, and the alert is a raw diff. SiteLetter takes a fresh screenshot of every monitored page every 24 hours and runs an AI classifier across each diff big enough to matter. A rotating hero, a sale banner, a date stamp gets auto-dismissed as cosmetic noise. A genuine content update lands in the next scheduled client report. A broken layout - a deploy that shifts the contact form behind a hero image, a CDN config that drops product photos, a stylesheet that 404s - is emailed after the next daily scan.
One billing unit covers a site, not a URL
UptimeRobot meters by monitor and each URL is a separate monitor. A typical client site needs uptime on the cart, the contact form, the FAQ, and the top product page - that is 4 monitors per site, counted against your plan cap. On the Solo plan (EUR 9/mo billed annually, and UptimeRobot prices in euros), one such client uses 4 of your 10 monitors before you have added Lighthouse, SSL, or anything else. SiteLetter meters by site: $5/site covers up to 15 pages - Lighthouse, screenshots, SSL, domain and broken-asset checks daily, uptime every minute on the homepage and every 15 minutes on sub-pages, sitemap re-synced weekly. No per-page tax.
Reports clients open, not status pages clients visit
UptimeRobot's client-facing surfaces are a public status page and an account-level monthly uptime email. Going by their published feature documentation as of the verification date below, neither is a per-client branded deliverable whose sections, cadence, and recipients you control. Agencies need that second shape: a scheduled report carrying your agency logo, brand colour, and reply-to address. SiteLetter is built around that flow end to end. The finished report lands in your inbox on your cadence, you forward it, and your client opens it with no SiteLetter login screen and no account creation.
A builder for the client email, not the status page
UptimeRobot lets you style a status page, and their monthly uptime email is an account-level summary rather than a per-client report you can restyle or schedule per client, going by their published feature documentation as of the verification date below. SiteLetter ships a drag-and-drop builder for the scheduled email: reorder Page Scores, Uptime, Visual Changes, Site Status, and Broken Links & Images; toggle individual metrics on or off; set weekly, bi-weekly, monthly, or quarterly cadence per client. Most agencies leave the default; the builder is there for the client who asks for a specific shape.
Setup that ends after the URL
Adding a client site to UptimeRobot is several decisions: one URL for uptime, separate SSL and domain monitors, alert rules per monitor, status page config. Adding the same client to SiteLetter is pasting one URL. The sitemap is auto-fetched, the 15 most important pages are picked by depth + sitemap priority + recency, every monitoring service turns on, and the report template is pre-built. Alert rules are agency-level: pick what you want to be told about once, and every client and every site inherits it, this one included. You add recipients and you are done.
To replicate this on UptimeRobot, you would need a stack
UptimeRobot covers one slice of the agency monitoring deliverable. The other slices come from separate tools that each carry their own subscription, account, and integration cost.
- 1 UptimeRobot (paid tier sized to your portfolio)Uptime, SSL, public status pages
- 2 A separate Lighthouse SaaSPer-page performance, accessibility, SEO scoring
- 3 A separate visual regression toolDaily screenshots, change classification
- 4 A custom report pipelineBranded weekly client emails (typically built in-house)
Three subscriptions, three accounts, plus the in-house glue to email a branded report on schedule. SiteLetter is one tool, $5/site, all of it included.
Feature-by-feature comparison
The full picture, grouped by category. Some of these are wins for SiteLetter (per-page services, branded reports). Some are wins for UptimeRobot (alert channels, infrastructure layer). The honest answer is "both."
| Feature | SiteLetter | UptimeRobot |
|---|---|---|
| Pricing model | ||
| Pricing unit | 1 site (up to 15 pages) | 1 URL = 1 monitor |
| Cheapest paid plan | $5/site (15 pages monitored) | EUR 9/mo billed annually, EUR 10/mo month to month, Solo with 10 monitors. UptimeRobot prices in euros. |
| Free tier for client work | 14-day free trial of paid features | Yes - 50 monitors, 5-min checks; commercial/client use allowed per their published terms as of June 19, 2026 |
| Monitoring data retention | 2 years (730 days) for Lighthouse, screenshots, asset checks and reports, uniform across every subscriber; raw uptime check samples roll off after 7 days, with incidents kept alongside the rest of the history | Tiered: Free 3 months / Solo 12 months / Team and Scale 24 months |
| Per-page services on a client site | ||
| Uptime checking | Homepage every 1 min + 14 subpages every 15 min | Each URL = 1 monitor at fixed cadence; 5 min (Free) / 60 sec (Solo) / 30 sec (Team) / 15 sec (Scale) |
| Lighthouse audits | Every monitored page, daily | Not offered |
| AI visual regression | Every monitored page, daily, classified | Change detection published as a separate free tool (hourly screenshot, before/after email, unclassified); not a monitor type inside the paid plans (checked August 21, 2026) |
| Broken asset detection | Every monitored page, daily | Not offered |
| Hostname-level services | ||
| SSL certificate expiry alerts | Yes | Yes |
| Domain expiry alerts | Yes | Yes |
| Sitemap auto-discovery | Yes (weekly sync) | No (every URL added manually) |
| Public status page | Not available | Yes (basic on free, full on paid) |
| Infrastructure monitoring | ||
| Ping (ICMP) monitor | No | Yes |
| TCP / UDP port monitor | No | Yes |
| DNS record / heartbeat (cron) monitor | No | Yes |
| Custom HTTP methods (POST/PUT for APIs) | No | Yes |
| 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 | Multiple worldwide regions |
| Reports your clients read | ||
| Scheduled client-facing email report | Yes (weekly, bi-weekly, monthly, quarterly) | No (status pages only) |
| Per-client branding (logo, color, reply-to) | Yes | No |
| Agency branding on every report | Yes (your logo, brand color, reply-to address, and your agency name as the sender) | Limited - "Whitelabeled status page" removes UptimeRobot branding from status pages on Team and Scale, but no branded client report is in their published docs (checked August 21, 2026) |
| Drag-and-drop report builder | Yes | No |
| Recipients view without a login | Yes (a branded email you forward; no account for the recipient) | No |
| Channels and integrations | ||
| Alert channels | Email, Slack | 15+ channels (Email, SMS, Voice, Push, Slack, Teams, Discord, PagerDuty, Telegram, etc.) |
| Public REST API | Not available | Yes (all plans) |
| Native mobile app | No | Yes (iOS, Android) |
Sources: uptimerobot.com/advanced-features, pricing, api. Verified .
Cost at your portfolio size
UptimeRobot's free tier covers basic homepage uptime; this compares the paid coverage you would need to match SiteLetter's full per-page deliverable. Drag the slider to your client portfolio size. Numbers update live.
UptimeRobot prices in euros, so every figure here is EUR and nothing is converted to dollars. These are their annual rates, the ones their pricing page shows beside the struck-through monthly price, checked August 21, 2026. Month to month the same rungs are EUR 41 Team and EUR 77 Scale. Their published ladder stops at 500 monitors (EUR 149/mo billed annually); above that they quote on request rather than listing a price.
Reading these numbers honestly
SiteLetter wins on cost-per-deliverable. SiteLetter at $5/site includes Lighthouse on every monitored page, AI visual regression, and a branded weekly or monthly client report. Matching them on UptimeRobot means adding two more tool subscriptions on top of it, a Lighthouse service and a visual-regression service, each with its own bill and account, plus the in-house glue to email a branded report on schedule.
UptimeRobot wins on uptime-only cost at scale. If your need genuinely is uptime-only at high volume, UptimeRobot's Scale tier is cheaper per monitor. SiteLetter is not hiding that. But the calculator number alone is not the comparison agencies are making.
Cost at common portfolio sizes
UptimeRobot's free tier can cover basic homepage uptime; the paid tiers below are sized to match SiteLetter's per-page coverage. Either way, the UptimeRobot column does not include Lighthouse or a branded client report, and page-change detection is a separate free tool rather than part of these plans.
| Client sites | SiteLetter | UptimeRobot: matching coverage (15 monitors/site), in EUR | UptimeRobot: homepage only (free tier, 1 monitor/site) |
|---|---|---|---|
| 5 | $25/mo | EUR 35/mo | Free |
| 10 | $50/mo | EUR 65/mo | Free |
| 20 | $100/mo | EUR 149/mo | Free |
Source: uptimerobot.com/pricing, verified .
Where UptimeRobot genuinely wins
UptimeRobot has been around since 2010 and the product depth shows. If you only need uptime (no Lighthouse, no classified day-over-day visual regression, no branded client report), or you are not running an agency where monitoring is part of a client deliverable, UptimeRobot is the better fit. The wins below are real and SiteLetter does not currently match them.
A genuinely generous free tier
Fifty monitors at a 5-minute cadence, free, and explicitly cleared for commercial and client use per their published terms as of June 19, 2026. If all you need is a simple up/down alert on a handful of sites, that is hard to beat at zero cost. SiteLetter has a 14-day trial but no permanent free tier.
Faster check intervals on paid tiers
UptimeRobot monitors from four regions (North America, Europe, Asia, Australia), verifies failures from a secondary region before opening an incident, and probes as often as every 30 seconds from their Team plan up, or every 15 seconds on Scale (their published pricing, checked August 2026). SiteLetter checks the homepage every minute from the EU and re-verifies any failure from a US region before opening an incident, with an AP region breaking ties. Sub-pages are swept every 15 minutes. Monitoring data is stored in the EU. Screenshots go to OpenAI in the US for visual change classification, under EU Standard Contractual Clauses. The two-region-verification pattern is similar in shape, but UptimeRobot has many more vantage points and sub-minute cadence. If you need that level of geographic granularity or 30-second resolution on production infrastructure, UptimeRobot wins clearly.
Alert channel breadth + native mobile app
Email, SMS, voice call, native iOS / Android push, Telegram, Slack, Teams, Discord, PagerDuty, Splunk On-Call, plus webhooks. SiteLetter ships email and Slack. Other alert channels and a mobile app are not available.
Infrastructure-layer monitors + public REST API
Cron heartbeats, ping (ICMP), TCP and UDP port checks, DNS record monitoring, custom HTTP methods and headers for Basic Auth and authenticated APIs - plus a public REST API on every tier. SiteLetter monitors public-facing pages only. A public API is not available.
For DevOps teams, infrastructure operators, hobby and personal sites, open source projects, and any single-purpose uptime use case, UptimeRobot 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. Per-page coverage, 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 built in.
Pure-uptime ops at scale
DevOps, SREs, and infrastructure teams running their own services. Cron heartbeats, ping/TCP/UDP, DNS records, custom HTTP methods, many more probe locations, 30-second intervals, SMS and PagerDuty paging. UptimeRobot ships these well; SiteLetter does not ship most of them.
Personal, hobby, or small + simple
Personal sites, side projects, or a few low-stakes client sites where a simple up/down alert is the whole job. UptimeRobot's free tier covers this at zero cost and allows client use per their published terms as of June 19, 2026. SiteLetter is built around the client report, so it is overkill here; UptimeRobot is the right pick.
SiteLetter vs UptimeRobot: FAQ
No. UptimeRobot briefly restricted its free plan to non-commercial use in late 2024, but it reversed that change. The current Terms of Service and Fair Use Policy state UptimeRobot is "available for any use, including commercial and business use," and the help center explicitly welcomes "freelancers and small businesses keeping a handful of client or company sites online" on the free plan. So if you remember the old ban, it no longer applies: an agency can monitor client uptime on the free tier today. The reason to look past UptimeRobot is not its terms, it is that uptime alone is not the agency deliverable. Source: uptimerobot.com/terms-fair-use.
Not the ones that make up a client deliverable. UptimeRobot prices in euros, and their paid tiers (Solo at EUR 9/mo billed annually for 10 monitors or EUR 19/mo billed annually for 50, Team at EUR 35/mo billed annually for 100, Scale at EUR 65/mo billed annually for 200 or EUR 149/mo billed annually for 500) buy you more monitors, faster check intervals, and full-featured status pages. What they do not add at any tier is Lighthouse audits, classified day-over-day visual regression, or a scheduled branded client report. Those are a different category of product, and they are what an agency actually bills a care plan for. SiteLetter at $5/site covers uptime plus all of that in one tool.
No. UptimeRobot tracks uptime and response time on each monitor but does not run Google Lighthouse audits, so there is no Performance, Accessibility, SEO, or Best-Practices score in the product. SiteLetter audits every monitored page on every site daily, with DNS/TLS/CDN cache warmup so scores are stable enough to show clients as a real trend.
Not inside the monitoring plans. UptimeRobot publishes a free website change detection tool that screenshots a page hourly and emails a before/after image when it spots a difference, but it is a standalone free tool rather than one of the monitor types on their website-monitoring page, and the email is a raw diff you triage yourself. SiteLetter screenshots every monitored page on every site daily, diffs them against yesterday, and sends every meaningful diff to an AI classifier that labels it as noise (rotating ads or banners) which is auto-dismissed, intentional updates which are logged in your weekly report, or real breakage (missing images, layout collapse) which triggers an alert email as soon as that day's scan finishes.
Not in the agency-deliverable sense. UptimeRobot ships public status pages (basic on free, full-featured on paid), which are useful but are pages your client visits, not a branded report you can put in front of them. SiteLetter is built around the email report flow: per-client logo, brand color, custom reply-to address, and your agency name as the sender name, plus optional agency branding that takes "SiteLetter" out of the report body. The finished report lands in your inbox on your cadence and you forward it, so your client never sees a SiteLetter login and never creates an account.
On pure uptime, no - UptimeRobot is comparable to SiteLetter at small portfolios and cheaper at larger ones. They price in euros, and their annual ladder runs EUR 9/mo for 10 monitors, EUR 19/mo for 50, EUR 35/mo for 100, EUR 65/mo for 200 and EUR 149/mo for 500, above which they quote on request. At 20 client sites with 15 pages each (300 monitors) UptimeRobot is EUR 149/mo billed annually on the 500-monitor Scale tier vs SiteLetter at $100/mo. Those are different currencies and this page does not convert between them. The real difference is what each plan covers - SiteLetter includes Lighthouse, classified visual regression, and branded client reports at that price; UptimeRobot's plans cover uptime, so matching the agency feature set means adding 2-3 more tools on top of the UptimeRobot subscription. The cost calculator above lets you check specific portfolio sizes.
Probe locations across four regions, North America, Europe, Asia and Australia (their published pricing, checked August 2026) (SiteLetter triangulates from 3: EU primary + US verifier + AP tiebreaker, monitoring data stored in the EU; screenshots go to OpenAI in the US under SCCs), more alert channels (SMS, voice call, mobile push, PagerDuty, Splunk On-Call, Telegram, Discord, Microsoft Teams, Mattermost, Pushover, Pushbullet, in addition to email and Slack), 30-second monitoring intervals from the Team plan up, and 15-second on Scale, infrastructure-layer monitors (ping, TCP/UDP port, DNS records, cron heartbeats, custom HTTP methods for authenticated APIs), a public REST API on every plan including Free, and a native mobile app. If those are part of your buying criteria, UptimeRobot is the better tool today.
Per-page Google Lighthouse on every monitored page daily with DNS/TLS/CDN cache warmup (UptimeRobot is uptime + status pages, no Lighthouse audits). AI day-over-day visual regression that classifies each diff big enough to matter as noise / intentional / breakage (UptimeRobot's page-change detection is a separate free tool that emails an unclassified before/after). Branded scheduled per-client email reports with per-client logo, brand color, reply-to (UptimeRobot email is alert-only, 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 (UptimeRobot is per-monitor manual definition).
Yes, and the SiteLetter setup is usually shorter than the original UptimeRobot one. Each SiteLetter site covers up to 15 pages automatically (sitemap-discovered and ranked by depth, sitemap priority, and recency), so a 100-monitor UptimeRobot setup typically collapses into 7-10 SiteLetter sites. That figure assumes those monitors are extra pages of domains you already cover: the collapse is per domain, not per monitor. A hundred monitors 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. Migrating 100 monitors does not mean re-creating 100 alert configurations: alert rules are set once at agency level and inherited by every client and every site. The 14-day free trial includes one site so you can validate the full experience on one client site before bringing the rest over.
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Comparison based on publicly available UptimeRobot terms, Fair Use policy, and feature documentation, last verified . Pricing was read separately from their pricing page on August 21, 2026, which is the date the figures in the calculator carry. UptimeRobot is a trademark of its respective owner, used here for identification and comparison purposes only. SiteLetter is independent and not affiliated with, sponsored by, or endorsed by UptimeRobot. For the most current UptimeRobot pricing and feature information, see uptimerobot.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.