Insights on Reliability & Monitoring

Best practices, tutorials, and engineering deep-dives from the Heimdall team to keep your applications running flawlessly.

Daniel MorganinReliability & Uptime

Why DNS is the Silent Killer of High Uptime

DNS failures are often invisible to internal monitoring systems. Learn how recursive resolution chains and TLD latency can silently take down your infrastructure.

Mar 1

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8 min read

Why DNS is the Silent Killer of High Uptime

Ethan WalkerinReliability & Uptime

What Actually Causes Downtime in Modern Web Applications

Downtime in modern web applications is rarely caused by a single failure. In practice, outages usually happen because multiple small issues align across multiple layers.

Feb 28

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3 min read

What Actually Causes Downtime in Modern Web Applications

Ethan WalkerinSSL, Domains & Trust

Postmortem: When Expired Certificates Take Down Global Infrastructure

A technical analysis of how major companies still suffer devastating outages due to missed certificate renewals and internal monitoring gaps.

Mar 15

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3 min read

Postmortem: When Expired Certificates Take Down Global Infrastructure

Daniel MorganinSSL, Domains & Trust

The Hidden Risks of Certificate Revocation (CRL & OCSP)

When a private key is compromised, revocation is suppose to protect you. Explore why CRLs and OCSP fail in production environments.

Mar 15

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4 min read

The Hidden Risks of Certificate Revocation (CRL & OCSP)

Ethan WalkerinSSL, Domains & Trust

Why Wildcard Certificates Hide Production Failures

Wildcard certificates are convenient but create massive blast zones. Learn how an expiring wildcard takes down dozens of subdomains simultaneously.

Mar 15

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4 min read

Why Wildcard Certificates Hide Production Failures

Daniel MorganinSSL, Domains & Trust

How to Monitor Automated Let's Encrypt Renewals

Automated renewals fail silently. Learn the common failure modes of ACME challenges and why you must monitor the endpoint, not the cronjob.

Mar 15

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4 min read

How to Monitor Automated Let's Encrypt Renewals

Daniel MorganinSSL, Domains & Trust

Debugging "Certificate Chain Incomplete" Errors in Production

Learn how to isolate, diagnose, and fix missing intermediate certificates causing intermittent TLS handshake failures.

Mar 15

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4 min read

Debugging "Certificate Chain Incomplete" Errors in Production

Ethan WalkerinSSL, Domains & Trust

The Complete Guide to Automated SSL Certificate Monitoring

A comprehensive guide to TLS lifecycles, common expiration failures, and how to implement robust synthetic monitoring to catch certificate issues.

Mar 15

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5 min read

The Complete Guide to Automated SSL Certificate Monitoring

Daniel MorganinDNS & Networking

How to Fix DNS SERVFAIL Errors

SERVFAIL means the resolution chain is broken. Learn how to fix DNSSEC validation failures and lame delegations to restore traffic immediately.

Mar 8

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4 min read

How to Fix DNS SERVFAIL Errors

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