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 the client's inbox - the deliverable UptimeRobot was never built to send.
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 now explicitly allows client use, 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; paid tiers from $7/mo add 1-minute 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 multi-region uptime probes with SMS, voice, or PagerDuty alerts. UptimeRobot ships those well today; SiteLetter does not ship most of them at all.
The free tier now allows commercial and client use, so for plain uptime on a handful of sites it is genuinely 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.
$$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 things below are not in the product at any tier - including Enterprise. They 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, including the $124/mo Enterprise tier. 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 can swing 15-20 points run-to-run, which is what makes most third-party Lighthouse data unusable for a monthly report.
Daily screenshots and AI-classified diffs
UptimeRobot does not screenshot a page or diff one against the previous day at any plan. SiteLetter takes a fresh screenshot of every monitored page every 24 hours and runs an AI classifier across each diff. 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 - gets emailed within the hour.
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 $7/mo Solo plan, 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 with every monitoring service running daily, no per-page tax.
Reports clients open, not status pages clients visit
UptimeRobot ships public status pages - useful, but they are URLs your client has to visit to see anything. Agencies need the opposite shape: a scheduled email that arrives in the client inbox carrying your agency logo, brand colour, custom CTA URL, and reply-to address. SiteLetter is built around that flow end to end. Recipients open the report straight from their inbox with no SiteLetter login screen and no account creation - new external addresses verify ownership once via a one-click link on first send; team members and returning recipients skip the step.
A builder for the client email, not the status page
UptimeRobot lets you style a status page. There is no scheduled monthly client report to style, because the product does not ship one. SiteLetter ships a drag-and-drop builder for the scheduled email: reorder Performance, Uptime, Visual Changes, SSL & Domain, Broken Assets, and Portfolio Overview; 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, alert rules seed themselves (SSL escalation 30/14/7/3/1 days, domain expiry, uptime retry verification, Lighthouse threshold), and the report template is pre-built. 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 (Team)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) | $7/mo Solo (annual, 10 monitors); $15/mo for 50 |
| Free tier for client work | 14-day free trial of paid features | Yes - 50 monitors, 5-min checks; commercial/client use now allowed |
| Monitoring data retention | 2 years (730 days), all data types, all subscribers | Tiered: Free 3 months / Solo 12 months / Team & Enterprise 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) / 1 min (Solo, Team) / 30 sec (Enterprise) |
| Lighthouse audits | Every monitored page, daily | Not offered |
| AI visual regression | Every monitored page, daily, classified | Not offered |
| 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 | Coming soon | 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), all data stored in EU | Multiple worldwide regions |
| Reports your clients receive | ||
| Scheduled client-facing email report | Yes (weekly, bi-weekly, monthly, quarterly) | No (status pages only) |
| Per-client branding (logo, color, reply-to) | Yes | No |
| Org-level white-label | Yes | No |
| Drag-and-drop report builder | Yes | No |
| Recipients view without a login | Yes (new external recipients confirm once; team members skip it) | No |
| Channels and integrations | ||
| Alert channels | Email, Slack | 15+ channels (Email, SMS, Voice, Push, Slack, Teams, Discord, PagerDuty, Telegram, etc.) |
| Public REST API | Coming soon | 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 pricing in USD, annual rate. Sourced from their public pricing page. Their published Enterprise ladder goes up to 1,000 monitors at $124/mo; above that is custom pricing.
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 2-3 separate tool subscriptions, each with its own bill, account, and integration cost.
UptimeRobot wins on uptime-only cost at scale. If your need genuinely is uptime-only at high volume, UptimeRobot's Enterprise 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, visual regression, or branded client reports - those are not in the product.
| Client sites | SiteLetter | UptimeRobot: matching coverage (15 monitors/site) | UptimeRobot: homepage only (1 monitor/site) |
|---|---|---|---|
| 5 | $25/mo | $29/mo | $7/mo |
| 10 | $50/mo | $54/mo | $7/mo |
| 20 | $100/mo | $69/mo | $15/mo |
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, visual regression, or branded client reports), 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 (per their current terms) explicitly cleared for commercial and client use. 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.
More probe regions + 30-second intervals
UptimeRobot monitors from multiple regions worldwide, verifies failures from a secondary region before opening an incident, and probes as often as every 30 seconds on Enterprise. SiteLetter confirms any down result across 3 AWS regions (EU primary + US verifier + AP tiebreaker, with all data stored in EU) on a flat 1-min cadence. 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 today; mobile app and channel breadth are on the post-launch roadmap.
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 and the API is post-launch roadmap.
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, multi-region probes, 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 now allows client use. 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. Paid tiers (Solo at $7/mo for 10 monitors or $15/mo for 50, Team at $29/mo for 100, Enterprise from $54/mo for 200 up to $124/mo for 1,000) buy you more monitors, faster check intervals, and full-featured status pages. What they do not add at any tier is Lighthouse audits, 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.
No. UptimeRobot does not screenshot pages or detect visual changes. SiteLetter screenshots every monitored page on every site daily, diffs them against yesterday, and uses AI to classify each diff 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 is emailed immediately.
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 scheduled email report sent to them. SiteLetter is built around the email report flow: per-client logo, brand color, custom CTA URL, custom reply-to address, optional org-level white-label that strips "SiteLetter" from the report. Recipients never see a SiteLetter login (new external addresses verify ownership once via a one-click link on first send; team members and returning recipients skip the step).
On pure uptime, no - UptimeRobot is comparable to SiteLetter at small portfolios and cheaper at larger ones. Their ladder runs $7/mo for 10 monitors, $15/mo for 50, $29/mo for 100, $54/mo for 200, $69/mo for 500, $124/mo for 1,000. At 20 client sites with 15 pages each (300 monitors) UptimeRobot is $69/mo on the 500-monitor Enterprise tier vs SiteLetter at $100/mo. The real difference is what each dollar covers - SiteLetter includes Lighthouse, visual regression, and branded client reports at that price; UptimeRobot covers uptime only, 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.
More probe locations across many worldwide regions (SiteLetter triangulates from 3: EU primary + US verifier + AP tiebreaker, with all data stored in EU), 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 on the Enterprise plan, 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 as noise / intentional / breakage (UptimeRobot does not screenshot pages or detect visual changes). Branded scheduled per-client email reports with per-client logo, brand color, reply-to, and a one-click confirm flow for new external recipients (UptimeRobot email is alert-only, not scheduled per-client deliverables). Sitemap auto-discovery: add a domain, SiteLetter picks the 15 most important pages and seeds monitoring rules (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. Add each unique site once and SiteLetter handles the rest: page selection, every monitoring service enabled, smart alert rules seeded (uptime, SSL and domain expiry escalations, Lighthouse threshold), weekly and monthly client report templates pre-built. 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, pricing, and feature documentation, last verified . 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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- ✓ 2-minute setup. Add a URL. SiteLetter auto-discovers pages, seeds alerts, schedules reports.
- ✓ No scripts to install. SiteLetter monitors from the outside, like a real visitor.
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