How do I set up alerts for latency spikes and error rate increases?

To set up alerts for latency spikes and error rate increases, you generally want to:

1. Collect the right metrics
2. Define a baseline
3. Create alert rules
4. Route notifications
5. Tune to reduce noise

1) Track key metrics

At minimum, monitor:

• Latency
  • p50 / p95 / p99 response time
  • request duration by endpoint
• Error rate
  • 5xx responses
  • failed requests / total requests
  • exceptions per minute

2) Choose alert thresholds

Good starting points:

Latency spike alert

Trigger if one of these happens:

• p95 latency > X ms for Y minutes
• p99 latency increases by Z% over baseline
• Latency is 2x normal for 5–10 minutes

Example:

• Alert if p95 > 500ms for 5 minutes

Error rate alert

Trigger if:

• Error rate > N% for Y minutes
• 5xx count exceeds a threshold
• Error rate is 2x baseline

Example:

• Alert if 5xx error rate > 1% for 5 minutes

3) Use a monitoring tool

Common options:

• Prometheus + Alertmanager
• Datadog
• Grafana Alerting
• New Relic
• CloudWatch / Azure Monitor / GCP Monitoring

4) Example alert logic

Prometheus-style examples

Latency:

histogram_quantile(0.95, rate(http_request_duration_seconds_bucket[5m])) > 0.5

Error rate:

sum(rate(http_requests_total{status=~"5.."}[5m]))
/
sum(rate(http_requests_total[5m]))
> 0.01

5) Send notifications

Connect alerts to:

• Email
• Slack / Microsoft Teams
• PagerDuty / Opsgenie
• SMS for critical issues

6) Reduce alert noise

To avoid false positives:

• Require the condition to persist for 5–10 minutes
• Use rolling windows
• Alert on percentage + absolute volume
• Separate warning vs critical
• Exclude known maintenance windows

Recommended setup

A practical starting point:

• Warning: p95 latency > 300ms for 10 min
• Critical: p95 latency > 500ms for 5 min
• Warning: error rate > 0.5% for 10 min
• Critical: error rate > 1% for 5 min

If you want, I can give you:

• a Prometheus/Grafana setup
• a Datadog monitor configuration
• or a cloud-specific example for AWS, Azure, or GCP.