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Guides and resources on uptime monitoring, SLAs, and building reliable services.

Fundamentals

Start here if you're new to uptime monitoring or want to understand the basics.

What is Uptime Monitoring?

A complete guide to monitoring website availability, detecting outages, and keeping services reliable.

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What is an SLA?

Service Level Agreements explained: uptime guarantees, what the numbers mean, and why they matter.

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SLA Uptime Levels

Compare 99.9% vs 99.99% vs 99.999% uptime. What each level means and which one you need.

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What is MTTR?

Mean Time to Recovery explained: how to measure and improve your incident response times.

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What is a Dead Man's Switch?

Heartbeat monitoring explained: how to detect silent failures in cron jobs and scheduled tasks.

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Incident Response Best Practices

Handle outages like a pro: from detection to resolution to postmortem.

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Free tools

Calculate, check, and reference—no account required.

Uptime/SLA Calculator

See what any uptime percentage means in real downtime per year, month, and week.

Use calculator

SSL Expiry Checker

Check any domain's SSL certificate expiration and details instantly.

Check SSL

HTTP Status Codes

Quick reference for HTTP status codes and what they mean.

View reference

Status Page Templates

Copy-paste templates for incident updates, maintenance notices, and postmortems.

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Postmortem Template

A lightweight, blame-free incident postmortem template with examples.

View template

Cron Heartbeat Helper

Generate heartbeat schedules and curl commands for cron job monitoring.

Use helper

Compare tools

Find the right monitoring tool for your team.

Pingdom Alternatives

Best alternatives to Pingdom for uptime monitoring.

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UptimeRobot Alternatives

Best alternatives to UptimeRobot for team monitoring.

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All Comparisons

Head-to-head comparisons of monitoring tools.

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