The Webalert Blog
Expert insights on website monitoring, uptime optimization, SSL management, and building trust with status pages.
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4xx Client Errors Explained: 400, 401, 403, 404 & 429
What 4xx HTTP client errors mean — 400, 401, 403, 404, 405, 408, 410, 429 — their causes, how they differ from 5xx, and how to monitor and alert on them.
May 30, 2026
10 min read
Cloud SLAs Compared: What AWS, Azure & GCP Actually Guarantee
Compare AWS, Azure and GCP uptime SLAs — what 99.9%, 99.95% and 99.99% really guarantee, how service credits work, and why the SLA is not your real uptime.
May 30, 2026
9 min read
RTO vs RPO Explained: Setting Disaster Recovery Objectives
RTO vs RPO made clear — what each means, how they differ, how to calculate them, how they relate to MTD, MTTR and backups, and how monitoring protects both.
May 30, 2026
9 min read
Apdex Score Explained: Measuring App Performance Satisfaction
What Apdex is, how the score is calculated from satisfied, tolerating and frustrated requests, how to set the T threshold, and where Apdex helps or misleads.
May 29, 2026
8 min read
HTTP/3 & QUIC Monitoring: What Changes and What to Watch
How HTTP/3 and QUIC change monitoring: UDP 443, 0-RTT, connection migration, fallback to HTTP/2, and the new failure modes and metrics you must watch.
May 29, 2026
9 min read
Latency Percentiles Explained: p50, p95, p99 & Why Averages Lie
Understand p50, p95, p99 and p99.9 latency percentiles, why averages hide outages, how to set SLOs on tail latency, and how to alert on the right number.
May 29, 2026
9 min read
ActiveRecord Monitoring: N+1, Slow Queries & Pool Exhaustion
Detect ActiveRecord N+1 queries, slow SQL and pool exhaustion in Rails. Bullet, Prosopite, pg slow logs, Sidekiq pool sizing, and HTTP latency as canary.
May 28, 2026
13 min read
AI Crawler Monitoring: Track GPTBot, ClaudeBot & PerplexityBot Traffic
Detect and monitor inbound AI crawler traffic from GPTBot, ClaudeBot, PerplexityBot, Google-Extended and more. User-agent IDs, IP ranges, robots.txt and alerts.
May 28, 2026
13 min read
Real User Monitoring (RUM) Explained: How It Works & When to Use It
RUM explained from first principles: what it measures, how it captures Core Web Vitals, beacons, sampling, privacy, when to use it and when synthetic wins.
May 28, 2026
13 min read
5xx Server Errors Explained: 500, 502, 503, 504 Fix Guide
Diagnose and fix HTTP 5xx server errors. What 500, 502, 503, 504 and Cloudflare 520-526 mean, common causes per code, and how to monitor each.
May 27, 2026
16 min read
Is My Website Down? How to Check From Outside in 60 Seconds
Find out if your website is really down or only down for you. Step-by-step external checks: DNS, ping, multi-region, third-party tools, and what to do next.
May 27, 2026
12 min read
Uptime Downtime Calculator: 99% to 99.999% Allowed Downtime
How much downtime does each uptime percentage actually allow? Full tables from 99% to 99.999% in seconds, minutes, hours and days per day, month and year.
May 27, 2026
11 min read