Most uptime monitoring tools can tell you when a site stops responding. Where they differ is how often they check, which parts of the world those checks come from, what has to happen before you're paged, and what it costs once your whole team needs a login.
A "15-second check" can describe very different systems. One service rotates that check between locations. Another checks from one place and brings in more only after a failure. Another runs it from every region you've selected, every cycle.
I run Sentinel, one of the nine services below, so this isn't an independent review. Every number about another product comes from that vendor's own pricing page or documentation, and each section says where that product is the better pick.
Pricing and features checked October 27, 2026. Vendors change plans often, so confirm current pricing before you buy.
The nine tools at a glance
| Service | Fastest check | Regions | How regions are used | Team access | Best fit |
|---|---|---|---|---|---|
| Sentinel | 15 sec | 15 | Every selected region, every cycle | 5 members on Pro, unlimited on Business | Fast outside-in monitoring for small teams |
| UptimeRobot | 15 sec | 4 | Checks rotate through selected regions | 3 seats on Team, 5 on Scale, extra seats paid | General-purpose monitoring |
| Better Stack | 30 sec | Multiple | Incidents verified from 3+ locations | Responder seats priced separately | Monitoring tied to on-call |
| Hyperping | 20 sec | 18 | Not published | 3, 10 or 20 seats, extra seats paid | Monitoring plus incident management |
| HetrixTools | 60 sec | 12 | Every selected location, every minute | Plan based | Cheap multi-location monitoring |
| Checkly | 10 sec (API) | 22 | Round robin, parallel on some plans | Plan and usage based | API and browser synthetics |
| Fettle | 30 sec | 3 | Every selected region, every interval | Flat plans | Small developer teams |
| OpenStatus | 30 sec | 28 | Not published, alerts when half fail | Unlimited on every paid plan | Open-source, large probe network |
| Uptime Kuma | 20 sec | Yours | Wherever you run it | Self-hosted | Self-hosting |
The column people skip is the fourth one. It's also the one that explains the most.
"Multi-region" means three different things
A service can advertise a global network without checking your endpoint from that network every time. There are three common models.
Rotating regions. Each normal check comes from one location, and the next check comes from the next location in your list. UptimeRobot documents this: checks cycle through your selected regions in order, one checker per check.
Failure confirmation. One location watches, and more locations are brought in once it sees a failure. You get a second opinion, but only after something already looks wrong.
Every region, every cycle. Every region you've selected checks during each interval. Sentinel, Fettle and HetrixTools all work this way. The requests don't need to land at the same instant to count. Sentinel, for one, spreads them across the interval so the target never sees a burst.
None of these is wrong. They answer different questions. If you only want to know whether a site is down, rotation with confirmation is fine. If you want to see your service from several parts of the internet all the time, and catch the DNS, CDN, TLS or routing failure that only one continent sees, you want the third model.
1. Sentinel
Best for small DevOps teams that want fast checks from every region without per-seat pricing
Sentinel checks websites, APIs and infrastructure from 15 regions on six continents. Every region you've selected (all 15 by default) checks each monitor during every interval, and that's true on every plan, Free included.
Business monitors can run every 15 seconds and Pro monitors every 30. Starter checks every minute and Free every five minutes.
An outage is declared when at least half of the selected regions fail, three or more of them, on at least two continents. With all 15 regions, that's 8 failing regions spread across two continents. Other regions are asked to check within seconds of the first failure, so a single region's network problem doesn't page anyone. How Sentinel confirms outages walks through the rule.
Check types cover HTTP and HTTPS with content and JSON assertions, ICMP ping, TCP ports, SSL certificates, DNS records, domain expiry, and heartbeats for cron jobs. There's a REST API, a CLI, a Terraform provider and an MCP server, plus alerts to Slack, PagerDuty, webhooks and more.
Where Sentinel stands out
It isn't the biggest network. OpenStatus lists 28 regions to Sentinel's 15.
What's different is the combination. Of the three uptime services here that document checking from every selected region on every cycle (Sentinel, Fettle and HetrixTools), Sentinel has the fastest interval at 15 seconds. It puts all 15 regions on the free plan, where HetrixTools Free gets four locations, OpenStatus Starter gets six per monitor and Fettle Free gets one region. And Business includes unlimited team members at $79 a month, so the fifth engineer costs the same as the first.
Things to consider
Sentinel is an uptime and infrastructure monitor. If you need scripted browser journeys like logging in or completing a checkout, Checkly and Better Stack go further.
Sentinel pricing
- Free: $0, 5-minute checks
- Starter: $14/month, 1-minute checks
- Pro: $29/month, 30-second checks, up to 5 team members
- Business: $79/month, 15-second checks, unlimited team members
Start monitoring with Sentinel
2. UptimeRobot
Best for straightforward, general-purpose monitoring
UptimeRobot is one of the most established dedicated uptime services, and it's still an easy place to start. The free plan includes 50 monitors at five-minute intervals.
Its pricing page lists 60-second checks on Solo, 30 seconds on Team and 15 seconds on Scale. Its help center article on intervals, dated July 2026, gives slower figures for Team and Scale, so confirm with them which applies to you.
It covers HTTP, keyword, ping, port, heartbeat, DNS, SSL and domain monitoring, with status pages and a long list of integrations.
The multi-region difference
UptimeRobot monitors from up to four regions: North America, Europe, Asia and Australia. Its locations guide says normal checks cycle through your selected regions in order, one checker per check. When a check fails, the rechecks run from a different data center in the same region.
That's a sound way to catch outages. It's a different thing from watching your service from every region all the time. If UptimeRobot is what you're moving away from, here's a direct comparison and a broader look at UptimeRobot alternatives.
Things to consider
Team includes three login seats and Scale includes five, with extra seats sold on top.
UptimeRobot pricing
Billed annually, Solo starts at $12/month, Team at $39/month and Scale at $79/month.
3. Better Stack
Best when uptime monitoring feeds an on-call process
Better Stack is broader than a conventional uptime monitor. Alongside external checks it offers incident management, on-call scheduling, logs, metrics and browser transaction monitoring.
Uptime checks run as often as every 30 seconds, with multi-location and geo-specific checks, screenshots, traceroute diagnostics and a Terraform provider. Its website monitoring page says every HTTP and ping incident is verified from at least three locations before an alert goes out.
Where Better Stack stands out
If an outage should land straight in an on-call rotation with escalation policies, Better Stack does far more around the monitor than a dedicated uptime service. Its Playwright transaction checks also help when "does it respond?" isn't the real question. There's a Sentinel vs Better Stack comparison if you're choosing between the two.
Things to consider
Pricing is harder to compare with a flat plan. The pricing page includes 10 monitors, then charges $25 a month ($21 billed annually) per additional 50. Responder seats for on-call are priced separately at $29 to $34 per user per month.
4. Hyperping
Best for teams that want monitoring and incident management together
Hyperping combines uptime monitoring, status pages and on-call incident management. Its pricing page lists 18 monitoring regions, 30-second checks on Essentials and Pro, and 20-second checks on Business.
Where Hyperping stands out
It sits between a dedicated uptime monitor and a full incident platform, which suits teams that want both without assembling them from separate tools.
Things to consider
Hyperping charges for seats. Essentials includes 3, Pro 10 and Business 20, with each additional user billed monthly. It doesn't publish how its regions are scheduled, so ask whether every region checks each cycle if that matters to you.
Hyperping pricing
Billed annually, Essentials is $24/month, Pro $74/month and Business $249/month.
5. HetrixTools
Best for inexpensive monitoring from several locations
HetrixTools gets overlooked because it doesn't market itself like the newer platforms, but its model is solid. Every plan checks once a minute, and according to its uptime monitor page, the locations you've picked check your monitor throughout the minute, every minute.
An outage needs more than half of your selected locations to see the failure, from 2 of 3 up to 7 of 12. It also includes server monitoring, status pages, an API and MCP access on every plan.
Where HetrixTools stands out
The price is hard to beat. Professional is $9.95/month with 6 of its 12 locations, Business is $19.95 with 9, and Enterprise is $49.95 with all 12. Free gets 4.
Things to consider
One minute is the fastest interval on every plan. If you need 15- or 30-second detection, look elsewhere.
6. Checkly
Best for programmable API and browser monitoring
Checkly is the least traditional uptime monitor on this list. It's built around synthetic monitoring, meaning programmable API checks and Playwright browser checks that run your code against your app.
API checks can run as often as every 10 seconds. Team and Enterprise plans can use all 22 public locations, while Hobby and Starter get 6, with up to 3 per check. Its pricing page lists round-robin scheduling across locations on every plan and parallel scheduling on some, though the uptime and synthetic tables disagree on which.
Where Checkly stands out
If your team already writes Playwright tests or wants monitoring defined next to application code, Checkly is far more capable than a URL monitor. It answers "can a customer actually sign in and check out?", which a status code never will.
Things to consider
Pricing is built around check runs, so model it at the frequency and number of locations you'd actually use rather than the starting price.
7. Fettle
Best for small teams that want simple monitoring with API and MCP access
Fettle is a newer developer-focused service with simple plans. The free plan includes 20 monitors checked every three minutes from one region. Plus ($9/month) checks every minute from two regions, Pro ($19/month) uses three, and Max ($39/month) adds 30-second checks on up to 50 of its 300 monitors.
Its comparison page describes the same fan-out model as Sentinel: every selected region checks the monitor every interval, rather than rotating.
Where Fettle stands out
The plans are easy to read, and a REST API and MCP server come with every plan, free included.
Things to consider
Three regions is a small network next to most services here, and the 30-second option covers at most 50 monitors on the top plan.
8. OpenStatus
Best for open-source monitoring with a large probe network
OpenStatus is open source under AGPL-3.0 and self-hostable, with a hosted service on top. Its probe network is the largest here: 28 regions across three clouds (Fly.io, Koyeb and Railway). An alert fires when half your regions see the failure.
Starter checks every minute from up to 6 regions per monitor. Pro and Scale check every 30 seconds and can use all 28. It also has Terraform support, a CLI, private locations and per-region latency detail.
Where OpenStatus stands out
For broad geographic coverage plus monitoring as code, it's one of the strongest options available, and every paid plan includes unlimited team members.
Things to consider
Using all 28 regions takes Pro or Scale. Pricing climbs faster than most dedicated uptime services: Starter is $30/month, Pro $100 and Scale $500. Its pages don't say whether regions check in parallel each cycle or rotate.
9. Uptime Kuma
Best for self-hosted monitoring
Uptime Kuma is the one to start with if you want to run the monitor yourself. It's polished, supports a long list of monitor and notification types, includes status pages, and checks as often as every 20 seconds. There's no subscription and no seat pricing.
The trade-off is perspective. If it runs on one server in Virginia, you're monitoring the internet from Virginia. A routing problem that only hits users in Europe or Asia won't show up. You can build a distributed setup, but then you're running monitoring infrastructure on top of the infrastructure it watches.
More self-hosted options are in the open-source uptime monitoring tools comparison, and there's a Sentinel vs Uptime Kuma breakdown if you're weighing self-hosted against managed.
How to choose
Start with four questions rather than the longest feature list.
How fast do you need to know?
A five-minute monitor can miss nearly five minutes of downtime before it even looks. For a personal site that may be fine. For an API or a checkout, 15 or 30 seconds makes a real difference. Interval isn't the whole detection time, though. Confirmation and alert delivery happen after the first failed check.
What does "multi-region" mean to you?
Ask each provider how many regions check your endpoint during a normal cycle, whether locations rotate, whether extra regions only join after a failure, and what has to be true before an outage is declared.
The answers vary a lot. UptimeRobot rotates through four regions. HetrixTools checks from every selected location each minute. Sentinel checks from every selected region each cycle, at up to 15-second intervals. OpenStatus offers 28 regions and alerts when half of them fail. Those are four different systems behind similar marketing.
How many people need access?
Price the plan for the team you have. If five engineers need dashboards, compare the cost at five. UptimeRobot and Hyperping include a fixed number of seats per tier and charge for more. OpenStatus and Sentinel Business include unlimited members.
Monitoring or synthetic testing?
If the question is "is my API responding correctly?", an HTTP check with response assertions is enough. If it's "can a customer log in, fill a cart and pay?", you want browser synthetics, and Checkly or Better Stack are the better fit.
What I'd pick for each case
For fast monitoring with broad regional coverage, look at Sentinel and OpenStatus first. Sentinel goes down to 15 seconds with every region checking in every cycle and unlimited members at $79. OpenStatus has the larger network and strong monitoring-as-code support.
For simple general-purpose monitoring, UptimeRobot is still easy to recommend, especially on its free plan.
If a one-minute interval is enough, HetrixTools is the cheapest way to get real multi-location checks.
When monitoring has to feed on-call and incident response, Better Stack and Hyperping deserve the closer look.
Checkly is the specialist for browser and API synthetics.
Fettle is a tidy option for a small team that wants API and MCP access without a big platform.
And if self-hosting is the requirement, start with Uptime Kuma.
The bottom line
Features with the same name often describe different systems. "15-second checks" tells you frequency, not how failures are confirmed. "Global monitoring" tells you locations exist, not which of them check your service on a normal cycle. "Team plan" doesn't tell you what the fifth engineer costs.
Look past the feature names to the monitoring model behind them. That's where these nine tools actually differ.