HetrixTools vs FiveNines: Different Tools for Different Problems

Comparing monitoring tools is a bit like comparing hammers to screwdrivers. You can argue about which one is "better," but the real question is what you're actually trying to do. HetrixTools and FiveNines both call themselves monitoring platforms, but they're solving different problems for different people.

I'll be upfront: I'm writing this for the FiveNines blog, so take the comparison with appropriate skepticism. That said, I'll try to be honest about where each tool makes sense, because recommending the wrong tool helps nobody.

What HetrixTools is actually good at

HetrixTools started as an uptime and blacklist monitoring service, and that's still where it shines. If your primary concern is "is my website responding" and "is my mail server's IP on any blacklists," HetrixTools handles that well and has been doing it for years.

The blacklist monitoring in particular is something you won't find in most server monitoring tools. If you run mail servers or care about IP reputation, this is genuinely useful. HetrixTools checks your IPs against dozens of blacklists and alerts you when something shows up. For email deliverability, that kind of early warning matters.

Their free tier covers 15 monitors, which is generous if uptime checks are your main need. The interface feels dated (it looks like it was designed around 2010 and hasn't changed much since), but it works. Sometimes boring and reliable beats modern and flashy.

Where HetrixTools falls short is depth. The server monitoring exists, but it's surface-level: basic CPU, memory, and disk percentages collected every 60 seconds. If you want to understand why your server is slow, or track what's happening inside containers, or monitor whether your cron jobs actually ran, you'll hit walls quickly.

What FiveNines focuses on instead

FiveNines approaches monitoring from the other direction. Instead of starting with "is it up," it starts with "what's happening inside." The agent collects system metrics at up to 5-second intervals, which means you can actually see spikes and anomalies instead of averaging them away.

The depth goes beyond basic resource percentages. You get process-level visibility, Docker container metrics, Proxmox VM monitoring, database health checks for PostgreSQL and Redis, and tracking for web servers like Nginx and Caddy. If something's misbehaving on your server, you have the data to figure out what.

Cron job monitoring is built in, which sounds minor until you've been bitten by a backup script that silently stopped running three weeks ago. FiveNines tracks whether jobs run, how long they take, and whether they succeed, then alerts you when something breaks the pattern.

The dashboard system lets you build custom views and share them publicly if you want, which is useful for status pages or giving clients visibility without giving them login access.

The trade-off is a smaller free tier (5 servers versus HetrixTools' 15) and no blacklist monitoring. If IP reputation is your primary concern, FiveNines isn't the right tool.

The actual differences that matter

Forget the feature checklists for a minute. Here's what it comes down to:

Collection frequency affects what you can actually see. At 60-second intervals, a CPU spike that lasted 30 seconds might show up as a modest bump or disappear entirely into the average. At 5-second intervals, you see it. This matters more than people realize when you're trying to correlate events or catch intermittent problems.

Container and VM support is either essential or irrelevant depending on your infrastructure. If you're running Docker or Proxmox, having native visibility into what's happening inside those layers saves you from cobbling together separate monitoring. If you're running bare metal with traditional services, you don't care.

Blacklist monitoring is niche but important for the people who need it. If you don't run mail servers or care about IP reputation, it's a non-feature. If you do, HetrixTools has years of refinement here that FiveNines doesn't try to match.

Interface age is subjective, but if you're going to spend time in a dashboard, how it feels matters. HetrixTools is functional but dated. FiveNines is more modern, with drag-and-drop customization and a cleaner layout. Whether that's worth anything to you depends on how much time you spend looking at monitoring dashboards.

Pricing reality

HetrixTools offers more monitors on the free tier (15 vs 5), which makes it appealing if you have a lot of simple endpoints to check and don't need deep metrics.

FiveNines' paid plans scale differently: $9/month for 20 servers, $29/month for 50. You can also buy additional monitors individually without jumping to a higher tier, which avoids the annoying situation where you need 17 monitors and the only option is paying for 50.

For basic uptime monitoring across many endpoints, HetrixTools is probably cheaper. For deep monitoring of fewer servers where you actually want to understand what's happening inside, FiveNines' pricing makes more sense.

So which one

If you're a webmaster running a bunch of sites and you mostly care about "is it up" plus blacklist checks for your mail server, HetrixTools does that job at a reasonable price with a proven track record.

If you're a sysadmin or running DevOps for infrastructure where you need to understand system behavior, track containers, monitor scheduled jobs, and actually diagnose problems when things go wrong, FiveNines gives you the depth that HetrixTools doesn't attempt.

Some people run both: HetrixTools for uptime and blacklist monitoring, FiveNines for system metrics and diagnostics. That's not a bad approach if you have specific needs that span both use cases.

The worst choice is picking a tool that doesn't match your actual problem, then fighting with it for months before switching. Figure out what you're really trying to monitor, and pick accordingly.