Both Vigilmon and SpeedCurve measure something about how your website behaves from the outside. But they answer entirely different questions — and confusing them leads to gaps in your monitoring stack.
SpeedCurve asks: "How fast does your page load?" Vigilmon asks: "Is your site actually available?" These questions overlap at the edge — a page that doesn't load is both slow and down — but the tools that answer them are built for different jobs.
What SpeedCurve Is
SpeedCurve is a web performance monitoring platform built around the Core Web Vitals and synthetic performance testing. It continuously loads your web pages (from real browsers in controlled environments) and measures:
- Largest Contentful Paint (LCP) — when does the main content appear?
- Cumulative Layout Shift (CLS) — does the page jump around as it loads?
- Interaction to Next Paint (INP) — how quickly does the page respond to user input?
- Total Blocking Time (TBT), Time to First Byte (TTFB), and dozens of other performance metrics
- Visual progress (filmstrip and video of the page loading over time)
- Third-party tag performance (tracking scripts, ad networks, analytics)
- Performance budget alerting (alert when LCP degrades beyond your defined threshold)
SpeedCurve integrates with CI/CD pipelines so you can catch performance regressions before they reach production. It generates the rich, developer-friendly reports needed to understand why a page is slow and which code change caused a regression.
It is not designed to tell you when a page is down.
What Vigilmon Is
Vigilmon is an uptime and availability monitoring platform. It probes your HTTP endpoints, TCP ports, and SSL certificates from multiple geographic regions every minute (or every 30 seconds on paid plans), and alerts you immediately when a service becomes unreachable.
Key capabilities:
- Multi-region consensus: Vigilmon requires agreement from probes across multiple geographies before declaring a service down. A CDN hiccup in one region doesn't page your team — only confirmed, multi-location outages do.
- SSL certificate monitoring: Alerts you weeks before certificate expiry causes a production outage.
- TCP port monitoring: Verifies that non-HTTP services (databases, message queues, game servers) are reachable at the network level.
- Heartbeat monitoring: Confirms background jobs and scheduled tasks are completing successfully.
- Status page: Communicates service status to customers during incidents.
Vigilmon answers the binary question — up or down — quickly and reliably, not the nuanced question of whether a page's LCP is 2.1 or 3.8 seconds.
Inside-Out vs Outside-In
The most useful frame for understanding the difference:
SpeedCurve is inside-out performance monitoring. It measures what's happening inside a page load — which resources are slow, which scripts are blocking, where the layout is unstable. It requires a full browser environment to measure Core Web Vitals, because these metrics only exist in the context of rendering.
Vigilmon is outside-in availability monitoring. It makes the simplest possible request to your endpoint and checks whether it gets a valid response. No browser rendering, no JavaScript execution — just a clean, external check that your service is reachable and responding.
A service can be "up" (returns HTTP 200) but performing poorly (LCP of 5 seconds). That's SpeedCurve's problem. A service can be down entirely (connection refused, 503, timeout). That's Vigilmon's problem. When both happen simultaneously — your site is down and you don't know how it was performing before it went down — you need both tools.
Feature Comparison
| Feature | Vigilmon | SpeedCurve | |---|---|---| | HTTP availability checking | Yes | Partial (as a byproduct) | | TCP port monitoring | Yes | No | | SSL certificate monitoring | Yes | No | | Multi-region consensus | Yes | No | | Uptime alerts (Slack, email, webhook) | Yes | Performance alerts only | | Core Web Vitals monitoring | No | Yes | | Synthetic performance tests | No | Yes | | LCP / CLS / INP tracking | No | Yes | | Third-party tag performance | No | Yes | | Filmstrip / visual page load | No | Yes | | CI/CD performance regression | No | Yes | | Status page | Yes, included | No | | Heartbeat monitoring | Yes | No | | Self-hostable | Yes (open source) | No | | Free tier | Yes — 5 monitors, 1-min intervals | No (paid only) | | Pricing | From $0/month | From ~$39/month | | Target user | DevOps, reliability, small teams | Frontend developers, performance engineers |
When You Need SpeedCurve
SpeedCurve is the right tool when:
- Performance is a competitive differentiator for your business. E-commerce conversion rates are directly tied to LCP. Media sites live or die on Time to Interactive. If you've quantified the revenue impact of performance, SpeedCurve gives you the data to defend it.
- Your team ships frontend changes frequently. SpeedCurve's CI/CD integration catches performance regressions in pull requests before they reach users.
- You have a dedicated frontend performance practice. SpeedCurve's depth is most valuable to engineers who will act on filmstrip analysis, third-party tag reports, and bundle breakdown data.
- You're optimising for Google Search rankings. Core Web Vitals are a confirmed ranking signal. SpeedCurve makes them actionable.
When You Need Vigilmon
Vigilmon is the right tool when:
- You need to know the moment your service goes down. No dashboard, no manual check — an immediate alert via Slack, email, or webhook.
- You're monitoring non-web services. TCP monitoring covers databases, APIs, message queues, and any service that doesn't have an HTTP interface.
- SSL expiry is a risk. Vigilmon monitors certificate health continuously and alerts weeks before expiry.
- You want a status page without building one. Vigilmon's built-in status page communicates with customers during incidents.
- Budget is constrained. Vigilmon's free tier provides everything small teams need. SpeedCurve has no free tier.
- Alert noise is a problem. Multi-region consensus means your team is paged only when a real outage is confirmed across multiple geographies.
The Complementary Stack
For frontend-focused teams who care about both availability and performance, these tools aren't competitors — they cover different ground:
- Vigilmon tells you when your site is unreachable, SSL is expiring, or a background job has gone silent.
- SpeedCurve tells you how your pages are performing when they are reachable, and whether recent deployments changed that.
Running both gives you full external observability: availability assurance from Vigilmon, performance insight from SpeedCurve. For most teams, Vigilmon is the starting point — it's free, it covers availability, and it fills the gap that SpeedCurve explicitly doesn't address.
Conclusion
SpeedCurve is excellent at what it does. If Core Web Vitals are a serious business concern and your team has the frontend engineering capacity to act on detailed performance data, it's well worth the investment.
But SpeedCurve doesn't watch your endpoints. It doesn't page you when your API goes offline. It doesn't tell your customers whether your services are up.
Vigilmon does all of that — from $0/month, with no credit card required. For teams who don't yet have performance monitoring in place, start with availability: make sure you know the moment your service is down. Add performance monitoring when your users and your business demand it.
Start monitoring uptime at vigilmon.online — 5 monitors, 1-minute intervals, status page, Slack integration, free forever.
Tags: #monitoring #webperformance #uptime #corewvitals #devops #speedcurve