Uptime Monitoring Best Practices for SaaS Teams
Most teams discover their monitoring gaps the same way: a customer emails "is your API down?" and the dashboards are all green. This guide covers the practices that close that gap — what to monitor, how to probe it, how to alert on it, and how to keep the whole system trustworthy enough that people actually respond when it fires.
1. Monitor from outside your infrastructure
The single highest-leverage change for most teams. Internal health checks share fate with the systems they watch: when your load balancer misroutes, your DNS record expires, or your cloud region has a networking event, the service process is still "healthy" — and your internal checks keep passing while every real user gets a connection error.
External checks travel the same path your users do: public DNS resolution, TLS handshake, the load balancer, then your application. If any link in that chain breaks, the check breaks. Keep your internal metrics — they're invaluable for diagnosis — but make external checks the source of truth for "are we up?"
2. Check the endpoints that map to user outcomes
A passing /health endpoint proves the process is running, not that customers can log in. Build your check list from user-visible capabilities, then find the endpoint that proves each one:
- "Can users reach the app?" — HTTPS check on the main web origin, asserting status 200 and a body string that only renders when the app booted properly.
- "Does the API work?" — a check against a real read endpoint, not just
/health. Assert on response content, not just status code: a 200 serving an error page is still an outage. - "Can clients connect to non-HTTP services?" — TCP checks for databases, queues, SMTP, anything customers or integrations hit directly.
- "Will the site resolve and stay trusted?" — DNS checks for your records and SSL checks that warn weeks before a certificate expires. Certificate expiry is the most preventable outage in the industry, and it still happens to household names every year.
3. Choose check frequency by time-to-detect, not by habit
Your check interval sets a floor on detection time: with five-minute checks, a short outage can go four minutes unnoticed — or be missed entirely. Work backwards from your commitments. If you promise 99.9% monthly availability, your whole budget is about 43 minutes; burning five of them just noticing the problem is a bad trade. High-value endpoints deserve one-minute intervals; internal tools can live with five.
4. Require consecutive failures before alerting
The internet is noisy. A single failed probe can be a transient route flap, a brief GC pause, or the monitor's own network hiccup. Alert on the first failure and you train your team that alerts are usually false — which is how real outages end up ignored for twenty minutes.
The standard fix is a failure threshold: open an incident only after two or three consecutive failures. With one-minute checks and a threshold of two, you still detect within about three minutes, but a lone blip stays out of everyone's inbox. This is exactly what incident rules in Opsentry's uptime monitoring do: you choose the consecutive-failure count per service, and incidents open themselves when it's met.
5. Track response time, not just up/down
Services rarely jump from healthy to dead. They degrade: p95 latency creeps from 200ms to 900ms over a week as a query plan regresses or a cache empties. If you only record binary availability, that week of warning is invisible. Record latency on every check and watch the trend — "slow" is the prologue to "down," and catching it in the prologue is a calm Tuesday fix instead of a 2 a.m. page.
6. Alert where your team actually looks
An alert that lands in an unwatched inbox doesn't exist. Route notifications to the channel your team treats as urgent — Slack, Teams, Discord, Telegram, or a webhook into your paging tool — and route by audience: engineers get every state change, support leads get customer-impacting incidents, leadership gets critical ones. One audience is always forgotten: your customers. That's what a public status page is for — it answers "is it down?" so your support queue doesn't have to.
7. Measure and publish real uptime
Computed uptime from actual external checks — daily, 30-day, 90-day — keeps everyone honest. It powers SLA reporting, surfaces slow reliability erosion that no single incident explains, and (published on a status page) becomes a sales asset: procurement teams increasingly ask for availability history, and "see our public status page" is the best possible answer. If you're formalizing targets, start with SLA vs SLO vs SLI.
8. Close the loop: detection is step one, not the job
Monitoring that ends at "alert fired" leaves the hardest part — coordinated response and customer communication — to improvisation. Wire detection into an incident management workflow: check fails → incident opens with severity and affected service → team notified → status page updated → timestamped updates until resolution. When that path is automatic, your team spends outage minutes fixing the problem instead of deciding who posts what where. Our incident communication guide covers the messaging half.
The checklist
- External checks as the source of truth for availability
- Checks mapped to user-visible capabilities, asserting on content
- HTTP, TCP, DNS, and SSL expiry covered
- Check frequency derived from your time-to-detect target
- Consecutive-failure thresholds so alerts stay credible
- Latency recorded on every check, trends watched
- Notifications routed to channels people treat as urgent
- Uptime computed from real checks and published
- Detection wired into incident response and customer communication
Opsentry implements this whole list — external HTTP/TCP/DNS/SSL checks, failure thresholds, latency tracking, chat notifications, and a branded public status page — and it's free while in early access.