Choosing between Sentinel vs UptimeRobot usually comes down to one question: do you want a lot of monitors on a free plan, or a broader mix of monitoring types on a smaller allowance? Sentinel is a newer uptime, SSL, DNS, domain-expiry and heartbeat monitoring platform from Elbah Group, built around a simple free tier that includes every monitor type from day one. UptimeRobot is a long-established monitoring service best known for offering a generous number of free monitors. Both cover the core checks most sites need, but they draw the line between “free” and “paid” in different places. This guide compares the two platforms feature by feature, using each vendor’s own published plan details, so you can see where they overlap and where they genuinely differ before you commit to either.
Sentinel vs UptimeRobot at a Glance
| Sentinel (Free) | UptimeRobot (Free) | |
|---|---|---|
| Monitors | 3 | 50 |
| Uptime monitoring | Included | Included |
| SSL monitoring | Included | Included |
| DNS monitoring | Included | Included |
| Domain expiry monitoring | Included | Included |
| Heartbeat monitoring | Included | Included |
| Minimum polling interval | 5 minutes | 5 minutes |
| Historical data retention | 7 days | Approximately 3 months |
| Incident management | Not included | Included, with limited commenting |
| Maintenance windows | Not included | Included |
| Status pages | Not included | 1 basic status page |
| Login / team users | 1 | Single-user (no team seats) |
| Best suited to | Small sites wanting all monitor types on one free plan | Users who need a high monitor count and don’t mind a single monitor type mix |
What Is Sentinel?
Sentinel is a website and infrastructure monitoring platform from Elbah Group, covering uptime, SSL certificate, DNS, domain expiry and heartbeat monitoring. Rather than gating monitor types behind separate plans, Sentinel’s free tier includes access to all five monitoring categories, capped at three monitors in total. This makes it a straightforward option for someone who wants to check a small number of endpoints across several dimensions — for example, one site’s uptime, its SSL certificate, and its domain expiry date — without needing to pick and choose which monitor types are available. Sentinel is positioned as a lean, modern alternative for small sites, side projects and early-stage products where monitor count matters less than monitoring breadth.
What Is UptimeRobot?
UptimeRobot is a long-running uptime and website monitoring service used by individuals, freelancers and businesses to track the availability of websites, APIs and services. It supports several monitor types, including HTTP/website checks, keyword monitoring, ping, port monitoring, SSL certificate monitoring, DNS monitoring, domain expiry monitoring and heartbeat (cron job) monitoring. UptimeRobot is widely known for its free plan, which allows up to 50 monitors checked every five minutes, along with a basic status page and maintenance windows. Paid tiers add faster check intervals, more monitors, additional team seats, longer data retention and more advanced status pages. According to UptimeRobot’s own fair use policy, the free plan can be used for commercial and business purposes, not just personal projects.
Sentinel Free vs UptimeRobot Free
| Feature | Sentinel Free | UptimeRobot Free |
|---|---|---|
| Price | £0/month | $0/month |
| Monitors | 3 | 50 |
| Login users | 1 | 1 (no additional login seats) |
| Notification users | 1 | Included, limited to 5 alert integrations |
| Minimum polling interval | 5 minutes | 5 minutes |
| Historical data retention | 7 days | Approximately 3 months |
| Uptime, SSL, DNS, domain expiry, heartbeat | All included | All included |
| Incident management | Not included | Included (can’t comment on incidents) |
| Maintenance windows | Not included | Included |
| Status pages | Not included | 1 basic status page |
The trade-off is clear: Sentinel’s free plan gives you a small number of monitors but full access to every monitoring category and a 5-minute polling interval that matches UptimeRobot’s free tier. UptimeRobot’s free plan gives you far more monitors and longer data retention, plus a status page and maintenance windows, but incident commenting is restricted and there’s no multi-user support. If you only need to watch one or two sites across several angles — uptime, SSL, DNS and expiry — Sentinel’s free plan covers that without any monitor-type restrictions. If you need to monitor many endpoints at once, UptimeRobot’s free plan will get further before you hit a limit. Try Sentinel free to see whether three fully-featured monitors are enough for your current setup.
Uptime Monitoring
Both platforms offer standard uptime monitoring with a 5-minute minimum check interval on their free plans. UptimeRobot additionally supports keyword, ping and port monitoring as distinct check types on its free tier, giving slightly more granularity in how “up” is defined. Sentinel’s uptime monitoring is a straightforward availability check, without the extra check-type variants UptimeRobot offers for free. Neither platform publishes sub-minute polling on its free tier; that capability sits behind paid plans on both providers. On Sentinel, the minimum polling interval drops to 60 seconds on the Individual and Team plans, and to 30 seconds on the Agency plan.
SSL Monitoring
SSL certificate monitoring is included free on both platforms, alerting you before a certificate expires or becomes invalid. This is one of the areas where Sentinel and UptimeRobot are functionally equivalent at the free tier: neither requires an upgrade to get certificate expiry alerts, which is notable since some competitors in this space reserve SSL monitoring for paid plans entirely.
DNS Monitoring
Both Sentinel and UptimeRobot include DNS monitoring on their free plans, allowing you to track DNS record changes or resolution failures. As with SSL monitoring, this is a category where the two products don’t meaningfully differ in what’s available for free — the difference is in how many monitors you can allocate to it, given Sentinel’s three-monitor cap versus UptimeRobot’s fifty.
Domain Expiry Monitoring
Domain expiry monitoring — alerting before a domain registration lapses — is included free on both Sentinel and UptimeRobot. For a small operation running only one or two domains, either free plan is sufficient on its own for this check. The practical difference again comes down to monitor allowance: Sentinel users need to weigh a domain-expiry check against their total of three monitors, while UptimeRobot users have much more headroom to run domain-expiry checks alongside dozens of other monitors.
Heartbeat Monitoring
Heartbeat (or “dead man’s switch”) monitoring, used to confirm that scheduled jobs and cron tasks actually ran, is included on both free plans. This is a monitor type that some competitors omit from free tiers entirely, so its inclusion on both Sentinel and UptimeRobot is worth noting for anyone monitoring background jobs rather than just public-facing endpoints.
Alerts and Integrations
UptimeRobot’s product supports a broad range of alert integrations across its plans, but the free tier limits this to around five basic integrations, including options such as Slack, Discord, Google Chat, Pushover and Pushbullet — webhook, Zapier and PagerDuty-style integrations are reserved for paid plans. Sentinel’s free plan includes one notification user, which handles alerting for the account. On Sentinel’s paid plans, the alert channels expand with each tier: Individual adds email (capped at 500 sends/month) and Discord; Team adds Microsoft Teams and Slack on top, with the email cap raised to 5,000/month; Agency adds phone call and SMS alerts (250 credits each), with email raised again to 25,000/month. When comparing alerting, it’s worth distinguishing what a product supports in principle from what’s actually unlocked on its free tier — UptimeRobot supports many more integrations overall, but most sit behind a paid plan, while Sentinel’s channel list grows in step with its three paid tiers.
Incident Management and Maintenance Windows
Sentinel Free does not include incident management or maintenance windows — this is disabled on the free plan. UptimeRobot’s free plan does include basic incident management and maintenance windows, though incident records on the free tier can’t be commented on or annotated with root-cause notes. Sentinel’s paid plans — Individual (£12/month), Team (£30/month) and Agency (£65/month) — all include incident management and maintenance windows; only Sentinel’s free plan lacks them. For teams that need to log incidents or schedule maintenance windows without paying anything, this remains a point in UptimeRobot’s favour at the free tier, since Sentinel requires at least the Individual plan to get the same capability.
Status Pages
Sentinel Free does not include public status pages. UptimeRobot’s free plan includes one basic status page, which is enough for a single project to communicate uptime status externally without paying. Sentinel’s paid plans — Individual, Team and Agency — all include public status pages; only the free plan lacks one. Anyone who needs a public-facing status page without paying will find UptimeRobot’s free tier more capable in this respect, but Sentinel matches that capability from its £12/month Individual plan upward.
Teams and Agencies
Neither product’s free plan is built for teams. Sentinel Free is limited to one login user and one notification user, so there’s no built-in way to share access on the free tier. UptimeRobot’s free plan is also effectively single-user, with no additional login seats — team collaboration on UptimeRobot starts at its Team plan, which adds multiple login seats and white-labelled status pages. Agencies managing monitoring for multiple clients will need a paid plan on either platform. UptimeRobot’s paid tiers and team seat counts are confirmed from its pricing page; Sentinel’s paid plans scale team access from 10 login users and 20 notification contacts on Team (£30/month) up to 25 login users and 50 notification contacts on Agency (£65/month), which makes the Agency tier the more direct fit for agencies running monitoring for several clients from one account.
Sentinel vs UptimeRobot Pricing
At the free tier, both products cost £0/$0 per month, with the trade-offs described above. Above the free tier, UptimeRobot’s entry-level Solo plan is priced at roughly $9–13 per month when billed annually (the exact figure varies slightly by displayed currency/region on UptimeRobot’s own pricing page), and includes 10 monitors with 60-second checks, 12 months of data retention and 3 login seats. UptimeRobot’s Team plan sits at roughly $38–45 per month, adding 100 monitors, 30-second checks and 5 login seats.
Sentinel’s paid plans, per its pricing page, are billed monthly at £12/month for Individual (with a 7-day free trial), £30/month for Team and £65/month for Agency. Sentinel does not publish an annual pricing option or discount. All three paid plans include incident management, maintenance windows and public status pages — these are the three features missing only from Sentinel’s free plan. The table below summarises what each tier adds:
| Individual | Team | Agency | |
|---|---|---|---|
| Price | £12/month | £30/month | £65/month |
| Monitors | 20 | 100 | 250 |
| Login users | 1 | 10 | 25 |
| Notification contacts | 2 | 20 | 50 |
| Min. polling | 60 seconds | 60 seconds | 30 seconds |
| Historical data | 30 days | 90 days | 365 days |
| Monitoring | Domain and SSL monitoring (without detailed history) | DNS monitoring, Domain and SSL monitoring (full) | DNS monitoring, Domain and SSL monitoring (full) |
| Alerts | Email (500/month), Discord | Email (5,000/month), Discord, Microsoft Teams, Slack | Email (25,000/month), Discord, Microsoft Teams, Slack, Calls (250 credits), SMS (250 credits) |
| Incident management | Included | Included | Included |
| Maintenance windows | Included | Included | Included |
| Status pages | Included | Included | Included |
Uptime and heartbeat monitoring continue from the free tier on every paid plan; Sentinel’s plan comparison specifically calls out Domain, SSL and DNS monitoring as what scales with each tier. Historical data retention scales with plan tier beyond the free plan’s 7 days: Individual includes 30 days, Team includes 90 days and Agency includes 365 days of historical data. Incident management, maintenance windows and public status pages are also confirmed as included on all three paid plans (Individual, Team and Agency) — only the Free plan lacks them.
- Free/early-stage: Sentinel’s free plan is a reasonable fit if you’re monitoring one to three endpoints and want SSL, DNS, domain-expiry and heartbeat checks bundled in from day one. UptimeRobot’s free plan is a better fit if you already have more than three endpoints to watch and can live without incident commenting or extra team seats.
- Solo developer: A solo developer who outgrows Sentinel’s 3-monitor free cap can move to Individual at £12/month for 20 monitors, 60-second polling, 30 days of historical data, email/Discord alerts, and incident management, maintenance windows and a status page — still well short of UptimeRobot’s 50 free monitors, but with a faster check interval and more included features than either free plan offers.
- Small team: Teams needing multiple login seats will find Sentinel’s Team plan (£30/month, 10 login users, 100 monitors, 20 notification contacts, 90 days of historical data, DNS/Domain/SSL monitoring, incident management, maintenance windows, a status page, plus Microsoft Teams and Slack alerts) a closer match than its free tier; agencies managing several clients should look at the Agency plan (£65/month, 25 login users, 250 monitors, 365 days of historical data, 30-second polling, plus call and SMS alert credits) instead.
Where UptimeRobot Is Better
UptimeRobot’s free plan is significantly more generous on raw monitor count — 50 versus Sentinel’s 3 — and includes a basic status page, maintenance windows and incident logging on its free tier, none of which are available on Sentinel’s free plan (Sentinel only adds these from its £12/month Individual plan upward). Data retention is also considerably longer on UptimeRobot’s free tier (around 3 months, versus Sentinel’s 7 days). For anyone who needs to monitor many endpoints, publish a public status page, or track incidents without paying anything, UptimeRobot’s free plan is the stronger option based on the data available.
Where Sentinel Is Better
Sentinel’s free plan bundles all five monitor types — uptime, SSL, DNS, domain expiry and heartbeat — without needing to reserve any of them for a paid tier, and without the alert-integration restrictions UptimeRobot applies to its free plan. For a small number of endpoints where the priority is checking multiple things about the same site (is it up, is the certificate valid, is the domain about to expire, did the cron job run) rather than watching many separate endpoints, Sentinel’s free plan covers that breadth from the outset.
Who Should Choose Sentinel?
- You’re monitoring a small number of sites or services (up to 3) and want all monitor types included without upgrading
- You want SSL, DNS, domain-expiry and heartbeat checks on the same monitors as uptime, rather than juggling separate tools
- You’re an early-stage project or solo site owner who doesn’t yet need incident logging, maintenance windows or a public status page — and if you do, these are included on every Sentinel paid plan from £12/month
- You’d rather start on a simple free plan and evaluate the product before committing to a paid tier
Who Should Choose UptimeRobot?
- You need to monitor more than a handful of endpoints without paying
- You want a public status page or basic incident logging included on a free plan
- You need longer historical data retention than a week
- You’re comfortable with a limited set of free-tier alert integrations and don’t need webhook or Zapier support until you upgrade
Sentinel vs UptimeRobot: Which Should You Choose?
Choose UptimeRobot when monitor count, status pages, incident logging or longer data retention matter most on a free plan, and you’re comfortable with a single monitor type mix across a large number of checks. Choose Sentinel when you have a small number of endpoints and want uptime, SSL, DNS, domain-expiry and heartbeat monitoring all included on the same free plan without restriction — and know that incident management, maintenance windows and status pages are ready to go the moment you move to any of Sentinel’s paid plans. Neither plan is a universal winner — the right choice depends on whether your priority is monitor volume or monitoring breadth on a small footprint. Try Sentinel if the latter describes your situation, and if your needs grow beyond the free plan, Sentinel’s paid tiers start at £12/month for Individual and scale up to £65/month for Agency.
Related Comparisons
For a broader look at how Sentinel compares across the market, see our guide to the Best Uptime Monitoring Tools & Sentinel Alternatives.
- Sentinel vs Better Stack — worth checking if incident response and on-call workflows matter as much to you as uptime checks.
- Sentinel vs StatusCake — another useful comparison if you’re also weighing page-speed monitoring and check-location coverage.
Frequently Asked Questions
Is Sentinel free?
Yes. Sentinel offers a free plan with 3 monitors, 1 login user, 1 notification user, a 5-minute minimum polling interval and 7 days of historical data retention. Uptime, SSL, DNS, domain expiry and heartbeat monitoring are all included on the free plan.
Is Sentinel a good alternative to UptimeRobot?
It can be, particularly if you have a small number of endpoints and want every monitor type available without upgrading. If you need a high monitor count, a status page or incident logging on a free plan, UptimeRobot’s free tier currently offers more; Sentinel offers the same status page and incident logging capability from its £12/month Individual plan.
Which has the better free plan?
It depends on your priority. UptimeRobot’s free plan allows more monitors (50 versus 3), longer data retention and includes a status page and maintenance windows. Sentinel’s free plan includes every monitor type on a smaller allowance with no restrictions on which checks are available.
Does Sentinel monitor SSL certificates?
Yes, SSL monitoring is included on Sentinel’s free plan, alongside uptime, DNS, domain expiry and heartbeat monitoring.
Does Sentinel support heartbeat monitoring?
Yes, heartbeat monitoring is included on Sentinel’s free plan, allowing you to confirm scheduled jobs and cron tasks are running as expected.
Does Sentinel’s free plan include a status page?
No, public status pages are not included on Sentinel’s free plan. They are included on all of Sentinel’s paid plans (Individual, Team and Agency). UptimeRobot’s free plan includes one basic status page.
Do Sentinel’s paid plans include incident management and maintenance windows?
Yes. Incident management and maintenance windows are included on all three of Sentinel’s paid plans — Individual (£12/month), Team (£30/month) and Agency (£65/month). Only the free plan excludes them.
How long does Sentinel keep historical data on paid plans?
Sentinel’s free plan retains 7 days of historical data. On paid plans, retention scales with tier: Individual includes 30 days, Team includes 90 days and Agency includes 365 days of historical data.
How much does UptimeRobot’s paid plan cost?
UptimeRobot’s entry-level paid plan, Solo, is priced at roughly $9–13 per month when billed annually, based on UptimeRobot’s own pricing page. Sentinel’s paid plans, by comparison, are billed monthly at £12/month for Individual (20 monitors), £30/month for Team (100 monitors, 10 login users) and £65/month for Agency (250 monitors, 25 login users), per Sentinel’s own pricing page.