The Best Uptime Monitoring Tools for Web Agencies

There are two ways to find out a client’s site is down. The first is your uptime monitor alerting you. The second is the client calling you.

You want it to always be the first one.

Uptime monitoring is one of those unsexy, behind-the-scenes parts of agency life that nobody talks about until something goes wrong. When it’s working, it’s invisible. When it’s not — or when you don’t have it — the consequences show up in your inbox at the worst possible time.

We asked the members of The Admin Bar what uptime monitoring tools they use and why they trust them. The answers covered everything from polished SaaS platforms to self-hosted open-source tools to fully custom-built solutions — with a clear standout in each category.

Here’s what the community had to say.

The Most Mentioned Uptime Monitors

• UptimeRobot
• WP Umbrella
• Uptime Kuma
• HetrixTools
• BetterStack
• updown.io
• Other Tools Worth Knowing

Why Agencies Choose These Uptime Monitors

UptimeRobot

UptimeRobot is the tool most agencies started with — and for many, it’s still part of the stack even as they’ve added others alongside it.

Blake Whittle has built a custom ClickUp integration on top of it:

“Uptime Robot with keyword monitoring. It’s the best. I made a custom webhook integration to ClickUp that creates a task if a site goes down, and once it recovers, it posts a comment to the same task and auto closes it.”

Blake Whittle

Donovan Shores uses it for all sites with email alerts, and adds SMS notifications to himself and the server company if an IP ping fails — treating a server-level failure differently from a site-level failure. Wesley Peace uses a self-hosted Uptime Kuma instance as his primary and UptimeRobot as a backup layer.

The friction points that came up: pricing has increased as lists grow, the interface has gotten more complex over time, and the free tier was reduced. David Innes manages 100+ sites and finds it “annoyingly expensive” at that scale. Peter Melling left specifically because of the free tier reduction.

UptimeRobot does have one genuinely useful feature worth calling out: domain expiration warnings. For agencies whose clients own their own domains, getting a heads-up before a domain lapses — before the site disappears entirely — is a practical benefit that goes beyond pure uptime monitoring.

Best fit: agencies managing a moderate number of sites who want a reliable, well-supported SaaS monitor with keyword checking and good notification options; less cost-effective at 100+ sites.

WP Umbrella

WP Umbrella came up repeatedly from agencies who’d previously used UptimeRobot and dropped it once they realized their site management platform already covered uptime monitoring.

“I used Uptime Robot for a long time, but WP Umbrella’s monitoring has been really good so I’m down to just that one. It’s part of the subscription so it saves me from having a separate tool.”

Erica Martin, Shanda Lynn Watts, Dennis Gram, Marion Paolo Abagar, Irene Koukia, and Clayton Mayo are all in the same camp — using WP Umbrella’s built-in monitoring rather than maintaining a separate service. Norris Girdy is actively switching from ManageWP to WP Umbrella partly for this reason.

The appeal is consolidation: if you’re paying for a WordPress management platform anyway, having uptime monitoring included removes a line item and one fewer dashboard to check. The tradeoff is that you’re monitoring from within the same platform that manages the sites — Rob Watson’s point about triangulating between multiple monitors to rule out false positives or checker-side issues is worth keeping in mind.

Best fit: agencies already using WP Umbrella for WordPress site management who want uptime monitoring without a separate tool or subscription.

Uptime Kuma

Uptime Kuma is a self-hosted, open-source uptime monitor — and it has become the go-to recommendation for agencies who want full control without an ongoing per-site cost.

Aaron Hilson runs it with keyword monitoring. Jordan Trask called it “decently easy to set up these days.” Wesley Peace uses it as his primary monitor and pushes alerts to a Discord channel. Mark Rudder and Aditya Sharma both self-host it on their own servers. Vinny Alves is in the process of migrating from UptimeRobot to Uptime Kuma. Lumia Zee is another advocate.

Chris Hunter’s custom-built monitor (more on that below) takes the self-hosted concept further, but for agencies who want the self-hosted benefits without building from scratch, Uptime Kuma is the community’s recommended starting point.

The main requirement is a server to run it on — but if you’re already managing VPS infrastructure for clients, adding Uptime Kuma is a straightforward addition that costs nothing beyond the server resources.

Best fit: technically comfortable agencies who want a self-hosted monitor with no per-site fees and full control over alerting and check frequency.

HetrixTools

HetrixTools came up consistently as the most generous free tier in the category — and the members using it were unanimously positive.

Michel Santos called it “the most reliable I’ve found, with the most generous free plan.” Meddy Brai echoed the sentiment. Alex Celeste uses it for non-WordPress sites and for monitoring the MainWP dashboard itself — a smart use case, since you want something external watching the tool that manages everything else. Peter Kuipers uses it at the server level. Greg Mount is a straightforward advocate: “Without hesitation. Very happy with this tool.”

Rufo Reyes flagged an additional feature worth knowing: HetrixTools includes blacklist monitoring — checking whether your server’s IP or domain has ended up on email blacklists, which can affect deliverability and is easy to miss until a client notices their emails aren’t getting through.

Best fit: agencies who want a generous free tier with solid reliability; especially useful for non-WordPress sites or as an external monitor for your management infrastructure.

BetterStack

BetterStack (formerly Better Uptime) positions itself as a more developer-oriented monitoring platform — and the members using it tend to appreciate the depth of features alongside the pricing.

Abhi S recommended it and David Innes did the math: at roughly $0.20 per site per month, it’s an appealing option for agencies managing 100+ sites compared to per-seat or flat-rate alternatives. Zunaid Khan, Tim Dickinson, and Tommy Kokko are all BetterStack users. Adam Wright uses it for status pages as well as monitoring: “I can even create a nice status page that I typically monitor when on vacation.”

Status pages are worth calling out as a feature: a public-facing status page gives clients a place to check during an incident rather than emailing you, which reduces support noise during outages.

Best fit: agencies managing larger site portfolios who want competitive per-site pricing, or those who want public status pages as part of their client-facing offering.

updown.io

updown.io runs on a pay-per-check model rather than a flat monthly fee — you buy credits and spend them based on how many sites you monitor and how frequently.

Rob Marlbrough called it his favorite for the graphs: “Superb graphs.” Peter Melling switched from UptimeRobot specifically after the free tier was reduced and has been happy since — including a case where it caught an IPv6 issue that IPv4-only monitors would have missed, since it checks both protocols. Mark Cherry made the same switch and called it “great and cost effective.”

The credit model is unusual but has a real benefit at scale: agencies with a mix of critical and lower-priority sites can check high-traffic sites more frequently and reduce check frequency on simpler sites, rather than paying the same flat rate for everything.

Best fit: agencies who want fine-grained control over monitoring frequency and cost; especially appealing for larger portfolios where a flat per-site fee adds up quickly.

Other Tools Worth Knowing

These also came up in the thread:

• Pulsetic — Jaime Alnassim has been using it for nearly two years without issues; Rob Marlbrough also uses it as part of his multi-monitor stack
• Uptime Kuma on Raspberry Pi — Rose Newell mentioned installing it on a Raspberry Pi at her parents’ house; a fun reminder that self-hosted monitoring doesn’t require a VPS
• MonSpark — Gerson El uses it (via an AppSumo deal) for DNS monitoring, screenshots, server monitoring, and more beyond basic uptime. Luke Humble uses both MonSpark and UptimeRobot together, with escalation rules for calling technicians on server-level failures
• Netumo — Marleen Kiral and Holger Gruenhagen both use it; Holger has a lifetime deal
• updown.io + Beszel — Rob Marlbrough pairs updown.io for uptime with Beszel for server resource monitoring, which catches resource issues before they cause downtime. He specifically called out being proactive rather than reactive
• HetrixTools + MainWP — Alex Celeste’s combination: MainWP uptime monitoring for WordPress sites, HetrixTools for everything else
• Flowguard — Vladimir Rechnov uses it; Meddy Brai is watching it as it matures; includes screenshot comparison before/after events which is a differentiator most pure uptime monitors lack
• updown.io + Upptime badges — Rob Marlbrough flagged Upptime badges as a clean way to display server status in support areas or client-facing pages
• Uptimia — Blue Li uses it with domain expiration monitoring included
• Garmingo Status — Linus Ahimsa uses it via an AppSumo deal

The Custom-Built Option

One of the most interesting contributions in this thread came from Chris Hunter, who built his own uptime monitoring system from scratch — and the approach is worth understanding even if you don’t plan to replicate it.

Rather than just checking for 404 and 403 errors, his system sets a baseline payload for each page (HTML, JS, CSS) and alerts if the payload changes by more than 20%:

“I think this is critical — a site may be functionally broken but not serving a 403 or 404 error. In that case, a standard uptime monitor won’t alert you that the site is having an issue.”

Chris Hunter

Notifications go to email and Slack, where he can use Cursor to investigate automatically. The whole thing runs on a $6/month VPS with no per-site fees. David Innes noted this is a meaningfully smarter approach than keyword monitoring alone, since a busted cache or broken CSS won’t trigger a standard uptime alert.

John White and Michael Kemp both took similar DIY paths — building their own monitors with Claude’s help rather than paying escalating SaaS fees as their site counts grew.

Patterns We Noticed

ManageWP’s uptime monitoring has become unreliable. Multiple members called this out independently: Elsie Gilmore, Norris Girdy, and Michael Kemp all flagged ManageWP uptime as flakey and are using or switching to alternatives. If you’re relying on ManageWP as your only monitor, it’s worth adding a secondary.

One monitor isn’t enough. Rob Watson runs up to three simultaneously — UptimeRobot, WP Umbrella, and whatever the client uses — specifically to triangulate whether a reported outage is real or a false positive from the checker itself. Wesley Peace uses Uptime Kuma as primary and UptimeRobot as backup for the same reason. The brief, mysterious 1–5 minute outages with no discernible cause are a recurring frustration — multiple monitors help distinguish a real issue from a routing blip.

Self-hosted is genuinely competitive. Uptime Kuma costs nothing beyond server resources. Chris Hunter’s custom solution runs on $6/month. As site counts grow, the economics of self-hosted versus per-site SaaS shift significantly. The agencies managing 100+ sites are almost all either self-hosting or actively evaluating it.

Standard uptime checks miss a class of real failures. Chris Hunter’s payload comparison approach and David Innes’s observation about cache failures both point to the same gap: a site can be “up” by a standard HTTP check while being functionally broken for visitors. Keyword monitoring helps, but even that won’t catch CSS being out of sync or a page builder template failing silently. It’s an unsolved problem for most agencies, and something worth building toward.

Consolidation wins when the platform already covers it. Several WP Umbrella users cancelled their standalone monitors once they realized the platform included uptime monitoring. For agencies who’ve already consolidated into a WordPress management platform, checking what’s already included before adding another tool is always worth doing.

How to Choose an Uptime Monitor

Just getting started with a small portfolio? UptimeRobot has a workable free tier and is the easiest entry point. HetrixTools has the most generous free plan in the category and is worth comparing.

Already using WP Umbrella? The built-in uptime monitoring is solid — check what you’re already paying for before adding a separate tool.

Managing 50+ sites and watching costs? Uptime Kuma self-hosted, updown.io‘s credit model, or BetterStack‘s per-site pricing are all worth evaluating. The math shifts significantly at scale.

Want server resource monitoring too? Beszel for server resources alongside your uptime monitor of choice. Being alerted to resource exhaustion before a site goes down is meaningfully better than finding out after.

Want to go further than standard HTTP checks? Keyword monitoring is the first step. Payload comparison (like Chris Hunter’s custom approach) or screenshot diffing (available in Flowguard and some MainWP setups) catches a class of failures that standard monitors miss entirely.

Frequently Asked Questions About Uptime Monitoring

What’s the best free uptime monitoring tool? HetrixTools has the most generous free tier according to this community. UptimeRobot also has a free plan, though the tier was reduced. Uptime Kuma is free if you self-host it on your own server.

How many uptime monitors do I need? More than one is the honest answer. Using a single monitor means you can’t distinguish a real outage from the monitor itself having a problem. Many agencies in this community run two — a primary and a secondary — and use discrepancies between them to filter false positives.

What’s the difference between keyword monitoring and standard uptime monitoring? Standard uptime monitoring checks whether a site returns a successful HTTP response (200 OK). Keyword monitoring checks whether a specific word or phrase appears in the response — useful for catching cases where a page loads but shows an error message, or where a database connection fails but the server still responds. Neither method catches a busted cache, broken CSS, or other visual failures.

Is self-hosted uptime monitoring worth the effort? For agencies managing a large number of sites, often yes. Uptime Kuma is free, actively maintained, and relatively straightforward to set up on any VPS. At 50+ sites, the monthly savings over a SaaS tool can be significant — and you get full control over check frequency and alerting.

Should my uptime monitor also watch domain expiration? It’s a useful addition. UptimeRobot and Uptimia both include domain expiration monitoring. For agencies whose clients own their own domains, getting advance warning before a domain lapses — before the site disappears — is meaningfully better than finding out at the same time the client does.