Response Time Monitoring & Latency Alerts

Uptime isn’t enough—slow feels “down.” UpDog tracks response time over time and sends alerts on slowdowns and latency spikes, so you can fix performance regressions before users bounce.

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Response time chart showing a latency spike and alert threshold

What is response time monitoring?

Response time monitoring measures how long it takes for your site or API endpoint to respond to a request—then tracks that latency over time. It turns “it feels slow” into a chart and a threshold you can actually alert on.

It matters because performance is part of reliability: slow pages hurt conversion and user experience, slow APIs break integrations, and increasing latency is often the first signal of an incident (long before you see a hard outage). It’s also a practical way to validate SLAs/SLOs with real data.

What UpDog measures

UpDog runs HTTP checks on a schedule and records the result over time. At a minimum, that includes the endpoint’s HTTP status code and the total request/response latency.

Teams typically monitor the endpoints that map to real user impact:

  • Homepage and key landing pages
  • Login and session endpoints
  • Checkout and payment flows
  • API endpoints used by customers, mobile apps, or partners

If you want a clean signal, consider monitoring a dedicated health endpoint alongside the “real path” URLs. That gives you both: “is the system alive?” and “is the experience fast?”

Catch slowdowns before they become outages

Most outages start as degradation. Response time monitoring helps you catch the early warning signs:

  • DB contention / slow queries: a steady climb in latency as the database fights for locks or a query plan regresses.
  • Third-party dependency lag: payments, auth, analytics, or email providers slowing down and dragging requests with them.
  • Deploy regressions: a release that adds a new hot path, heavier payloads, or a missing cache.
  • Resource saturation: CPU, memory, or connection pools hitting a limit and creating queues.
  • Queue buildup: background work backing up until the front-end requests start waiting.

Set thresholds that match reality

Alerting on “any slow check” gets noisy fast. A more reliable pattern is: alert when response time exceeds X ms for Y minutes. That catches sustained degradation while filtering temporary blips.

Practical starting points: many teams begin with 500ms for critical pages and 1000ms for heavier endpoints, then tighten or loosen based on what “normal” looks like for that specific URL. Your best thresholds come from your own history.

See trends, not just spikes

Spikes happen. What you care about is whether latency is drifting upward over hours, days, or after a deploy. UpDog keeps response time history so you can see trends, compare periods, and quickly answer: “when did this start?”

Use the chart to correlate slow periods with releases, incidents, traffic changes, or upstream provider events. Even without complex stats, a clear timeline makes debugging faster.

Alerts where you already work

Email and SMS are first-class alert channels in UpDog. Use them for simple coverage, or as a reliable “this will wake me up” backup.

If your team runs incidents in chat and on-call tools, you can also route response time alerts to your existing workflow via integrations.

How to set up response time monitoring

  1. Add a URL (website or API endpoint).
  2. Choose a check schedule + threshold that matches the endpoint.
  3. Pick alert channels (email, SMS, and/or integrations).

FAQ

Uptime monitoring tells you whether an endpoint responds at all. Response time monitoring tracks how long the request takes. You can be “up” and still be effectively down if pages and APIs are consistently slow.

It depends on what the endpoint does and what your users expect. For many web endpoints, teams often start with alert thresholds around 500ms–1000ms, then adjust based on your normal baseline and any SLAs/SLOs you’ve committed to.

Checks are simple HTTP requests on a schedule, similar to a lightweight health check. For most sites, the overhead is negligible. If you’re monitoring something expensive (like a heavy report), pick a lower-impact URL or use a longer interval.

You can monitor public API endpoints the same way you monitor websites. If an endpoint requires authentication, a dedicated health endpoint is usually the cleanest approach so you can measure the service without putting credentials into monitoring checks.

Instead of alerting on a single slow check, use a duration window—like “above 1000ms for 5 minutes.” That’s a strong signal of real degradation, and it keeps one-off blips from paging you.

UpDog measures request/response latency for an HTTP endpoint from our monitoring check, plus the HTTP status code. That’s different from Lighthouse, which simulates full page loading in a browser and includes front-end rendering and asset performance.

Checks run on a schedule you choose. Shorter intervals catch regressions faster, while longer intervals reduce noise and load. A good starting point is frequent enough to catch issues quickly, but not so frequent that you alert on every minor fluctuation.

Start by confirming it’s sustained (not a single spike), then check recent deploys and upstream dependencies. Look for rate/traffic changes, DB saturation, or timeouts. The goal is to narrow down whether it’s your code, your infrastructure, or a dependency dragging requests down.

Start with one “front door” URL (homepage or main app), one critical flow (login or checkout), and one API endpoint that represents core functionality. That combination catches most real-world incidents without turning monitoring into a project.

Yes. Latency is a core reliability metric alongside uptime. Monitoring gives you a historical record of response times that you can use to set targets, verify commitments, and spot when you’re trending toward a breach.

Related features

Round out response time monitoring with the rest of your reliability coverage:

Start catching latency issues early

Add a URL, set a threshold, and get alerted when response time climbs. It takes a minute—and it pays off the first time a “slow” incident hits.

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