DiagnosticsCore
How to Check if a Website Is Down: Complete Checklist
Step-by-step workflow to confirm outages, isolate local issues, and collect useful evidence.
Blog
Outage Troubleshooting Guides
44 practical guides with clear categories to help you investigate incidents faster, choose the right tools, and communicate better.
Looking for side-by-side tool evaluations? Visit Comparisons for benchmark-based checker reviews.
DiagnosticsHTTP
HTTP Status Codes Guide: 200, 300, 400, 500 Explained
Understand 2xx, 3xx, 4xx, and 5xx in plain English and route incidents faster.
DNSDiagnostics
DNS Outage Troubleshooting Guide
Diagnose NXDOMAIN, SERVFAIL, stale resolver cache, and propagation lag with confidence.
CDNRegional
CDN Outages and Regional Failures: A Diagnostic Framework
Use per-region checks to separate origin failures from edge routing and PoP-specific incidents.
SecurityTLS
TLS Certificate Errors vs Real Downtime
Certificate and handshake issues can look like downtime. Learn to tell the difference quickly.
Incident ResponseComms
Incident Communication Template for Website Outages
Ready-to-use customer update structure that reduces confusion and builds trust during incidents.
MonitoringStartup
A Practical Uptime Monitoring Stack for Startups
Build a cost-effective monitoring setup that scales from MVP traffic to production load.
MonitoringReliability
How to Reduce False Positives in Uptime Monitoring
Alert smarter with quorum logic, probe diversity, and better incident thresholds.
E-commerceIncident Response
E-commerce Outage: The First 30 Minutes Playbook
Prioritize recovery steps when revenue is at risk and checkout health degrades.
APIDiagnostics
API Downtime Investigation Playbook
Trace API incidents from edge to database with a clear, repeatable investigation path.
DiagnosticsIntermittent
How to Investigate Intermittent Outages
A practical method to capture transient failures that disappear before engineers can inspect them.
DeploymentsIncident Response
Website Down After Deploy: Recovery Checklist
Rollback and validation workflow for incidents that start immediately after a release.
CDNDiagnostics
Origin vs Edge Errors: A Decision Tree
Determine whether failures come from your origin stack or the edge path in under five minutes.
DatabasePerformance
Database Bottlenecks That Look Like Downtime
Recognize queue pressure, lock contention, and connection storms before full request collapse.
MonitoringDependencies
How to Monitor Third-Party Dependencies
Prevent blind spots when payment, auth, or analytics vendors degrade independently.
NetworkingBGP
BGP and Routing Incidents for Web Teams
Understand route leaks and path instability that can make healthy services look offline.
Incident ResponseComms
Status Page Best Practices During Outages
Build a status page process that reduces ticket volume and improves trust under pressure.
CMSWordPress
WordPress Site Down: Troubleshooting Guide
Fix common WordPress outage causes across plugins, themes, PHP workers, and database limits.
SaaSAuthentication
SaaS Login Outages: Auth and Session Failures
Debug identity-provider and session-layer failures that block users from signing in.
ResilienceArchitecture
Fail Open vs Fail Closed During Incidents
Choose safer fallback behavior under failure without creating larger operational risk.
AnalyticsIP Tools
How to Block Your IP in GA4: Internal Traffic Filter Setup
Step-by-step setup to exclude your own visits from GA4 using IP checker validation, testing mode, and safe activation.
ComparisonsDiagnostics
Best Website Down Checker Tools Compared (2026)
Head-to-head comparison of popular site down checkers with clear picks for support teams, operators, and incident triage.
ComparisonsIP Tools
Best IP Checker Tools Compared (2026)
Detailed comparison of leading "What is my IP" tools across IPv4/IPv6 visibility, ASN context, and automation fit.
ComparisonsDNS
Best DNS Lookup Tools Compared (2026)
Deep comparison of DNS tools for record depth, propagation checks, and outage-triage usability.
ComparisonsHTTP
Best HTTP Status Checker Tools Compared (2026)
Research-backed review of status-code tools for 2xx/3xx/4xx/5xx triage, redirects, and escalation workflows.
ComparisonsRouting
Best Redirect Checker Tools Compared (2026)
Compare redirect tools for migration QA, final URL consistency, and chain-level troubleshooting.
ComparisonsBrowser
Best User-Agent Checker Tools Compared (2026)
Evaluate parser accuracy, client-context depth, and ticket-ready outputs for QA and support teams.
HTTP CodesDiagnostics
What Does HTTP Status 200 Mean? (OK)
Why 200 can still hide user-impact issues and what to validate before closing an incident.
HTTP CodesDiagnostics
What Does HTTP Status 204 Mean? (No Content)
No Content explained in plain language: when 204 is healthy and when empty responses break user flows.
HTTP CodesDiagnostics
What Does HTTP Status 206 Mean? (Partial Content)
Understand partial-content responses for media, downloads, and range-request troubleshooting.
HTTP CodesDiagnostics
What Does HTTP Status 301 Mean? (Moved Permanently)
Understand permanent redirects, destination checks, and common redirect-chain mistakes.
HTTP CodesDiagnostics
What Does HTTP Status 302 Mean? (Found)
Decode temporary redirect behavior in auth, geo, and maintenance routing flows.
HTTP CodesDiagnostics
What Does HTTP Status 307 Mean? (Temporary Redirect)
Temporary method-preserving redirects explained for login and API routing reliability.
HTTP CodesDiagnostics
What Does HTTP Status 308 Mean? (Permanent Redirect)
Permanent method-preserving redirects for safe migrations and endpoint changes.
HTTP CodesDiagnostics
What Does HTTP Status 400 Mean? (Bad Request)
Learn when 400 indicates malformed requests versus broader platform instability.
HTTP CodesDiagnostics
What Does HTTP Status 401 Mean? (Unauthorized)
Practical triage for token failures, session drift, and identity-provider incidents.
HTTP CodesDiagnostics
What Does HTTP Status 403 Mean? (Forbidden)
Why reachable services still deny requests and how to separate blocking from downtime.
HTTP CodesDiagnostics
What Does HTTP Status 404 Mean? (Not Found)
Route-level missing content versus full outage, with recovery and redirect guidance.
HTTP CodesDiagnostics
What Does HTTP Status 408 Mean? (Request Timeout)
Request-timeout behavior explained, plus how to distinguish 408 from 504 quickly.
HTTP CodesDiagnostics
What Does HTTP Status 429 Mean? (Too Many Requests)
Rate-limit events in plain language and safe mitigation steps for production traffic.
HTTP CodesDiagnostics
What Does HTTP Status 500 Mean? (Internal Server Error)
How to triage internal server errors without guessing and reduce mean time to recovery.
HTTP CodesDiagnostics
What Does HTTP Status 502 Mean? (Bad Gateway)
Bad gateway failures across CDN, proxy, and origin boundaries with practical checks.
HTTP CodesDiagnostics
What Does HTTP Status 503 Mean? (Service Unavailable)
Service unavailable incidents, overload controls, and stabilization priorities.
HTTP CodesDiagnostics
What Does HTTP Status 504 Mean? (Gateway Timeout)
Gateway timeout root causes and fast checks for upstream latency and queue pressure.