AWS cost spikes: causes, checks, and alert policy.
AWS spikes are usually caused by resources that keep running, data transfer that compounds quietly, or managed services that scale faster than the team reviews billing.
What usually moves the AWS bill
EC2, ECS, or EKS capacity left running after a launch, migration, or load test.
NAT Gateway, cross-AZ transfer, CloudFront, or inter-region traffic increasing after architecture changes.
S3 storage, request, or retrieval costs rising after logs, backups, or analytics exports grow.
RDS, OpenSearch, Redshift, or Bedrock workloads scaling without a matching budget review.
Triage checklist
- Compare today against the trailing 7-day and 30-day provider baseline.
- Break spend down by service first, then by linked account, region, and tag.
- Review any new services or regions that appeared in the last 72 hours.
- Check whether committed-use discounts, savings plans, or reserved instances expired.
Green, amber, red thresholds for AWS
Green
Daily AWS spend is within 10% of baseline and forecast remains below budget.
Amber
Daily AWS spend is 10-25% above baseline, a new service appears, or forecast crosses 80% of budget.
Red
Daily AWS spend is more than 25% above baseline, a critical service spikes, or forecast exceeds budget.
Turn this playbook into a daily signal.
StackSpend connects AWS to your cloud and AI cost view with daily Slack or email reporting, anomaly detection, and pace-to-forecast.