Gaining Client-Side Visibility: AWS Embraces Network Error Logging (NEL)

Amazon Web Services (AWS) recently highlighted the utility of Network Error Logging (NEL), a web platform standard that allows browsers to report network-level failures (such as DNS resolution issues, secure connection/TLS handshakes, or TCP timeouts) directly to a specified collector.

For site reliability engineers (SREs), NEL fills a major visibility gap. Traditional monitoring tools only capture errors that successfully reach your application server or API gateway. When a user experiences a routing black hole, an expired SSL certificate, or a DNS misconfiguration, their request never registers on your backend. NEL acts as a client-side sentinel, sending reports asynchronously once a stable connection is re-established.

How Rabbit SaaS Enhances Client-Side Resilience

While NEL is excellent for detecting that client-side failures are occurring, SRE best practices dictate that we must prevent these failures before they ever disrupt the user journey. Here is how the Rabbit SaaS suite complements NEL insights:

1. Preventing TLS Failures with Certificate Guardian: NEL frequently flags client-side failures due to SSL/TLS handshake failures (such as expired or untrusted certificates). By deploying Certificate Guardian, you get proactive renewal alerts and Certificate Transparency (CT) log monitoring, ensuring your secure handshakes never fail in the wild.
2. Eliminating DNS & Domain Outages with Domain Audit HQ: Client-side DNS failures are a primary source of NEL reports. Domain Audit HQ provides continuous monitoring of domain expiration dates, DNS records, and WHOIS updates, preventing silent domain expirations or unauthorized DNS changes.
3. Decoupled Incident Communication via Status Navigator: If systemic network failures occur, your primary application may be unreachable. Hosting your custom-branded incident status page on Status Navigator ensures that your status communication is served on an isolated infrastructure, keeping customers updated even when client-side connectivity to your core app is degraded.

Combining proactive monitoring with modern observability standards like NEL is the key to achieving zero-downtime client experiences.