How many months of data do I need?

At minimum, 2 billing periods in the file. BillSpike compares your two most recent periods to identify what changed.

Is my raw billing file stored?

No. Your file is uploaded directly to S3 via presigned URL, processed, then permanently deleted. Only the analysis findings are retained. BillSpike never stores your raw billing data.

What is the difference between vol and price in the results?

vol means you used more of the service — your usage volume increased. price means the effective unit cost went up, often because a Reserved Instance or Savings Plan expired and the workload fell back to on-demand rates.

Does BillSpike need IAM access to my AWS account?

No. BillSpike only needs the exported CUR or FOCUS file. You export it from your cloud console and upload it. No credentials, no IAM roles, no cloud account access required.

What file formats does BillSpike support?

AWS CUR 1.0 and 2.0 (CSV and Parquet), FOCUS 1.x exports from AWS, Azure, and GCP, gzipped CSV (.csv.gz), and Parquet (.parquet, .snappy.parquet). Format and cloud provider are auto-detected on upload.

2026-03-22 · AWS Cost

How to Set Up AWS Billing Alerts

AWS does not send you a warning when your bill is about to get painful. By default, you find out at the end of the month when the invoice arrives. Billing alerts fix that, and they take about ten minutes to set up.

There are two tools worth knowing: CloudWatch Billing Alarms and AWS Budgets. They serve slightly different purposes and work best together.

CloudWatch Billing Alarms

CloudWatch billing alarms watch your estimated monthly charges and trigger when the total crosses a threshold you set. They are the simplest option and good for catching absolute cost overruns.

To set one up, go to CloudWatch in the console. Make sure you are in us-east-1, as billing metrics are only available in that region. Go to Alarms, then Create Alarm. Under the metric browser, select Billing, then Total Estimated Charge. Set your threshold, choose SNS as the notification method, and create or select a topic with your email address.

You will get an email confirmation for the SNS subscription. Confirm it, and the alarm is live.

The main limitation is that CloudWatch billing alarms only fire when the total crosses the threshold, not when spend is trending toward it. You also have to create a separate alarm for each service if you want per-service visibility.

AWS Budgets

AWS Budgets is more flexible. You can create alerts based on actual spend, forecasted spend, or usage. Forecasted alerts are particularly useful because they fire before you hit the threshold, giving you time to act.

To create a budget, go to AWS Billing in the console and select Budgets. Create a new budget, choose Cost Budget, and set your monthly amount. Under alert thresholds, add one at 80 percent of actual spend and another at 100 percent of forecasted spend. Put your email in the notification settings.

The forecasted alert at 100 percent is the one that actually helps. If AWS predicts you will overspend based on the current month's trajectory, you get the alert mid-month rather than after the damage is done.

AWS Budgets also lets you filter by service, account, tag, or region. If you want separate alerts for EC2 and RDS, you can set that up with two budgets and different filters applied.

Cost Anomaly Detection

Both of the above tools work against fixed thresholds. Cost Anomaly Detection is different. It uses machine learning to learn your normal spend patterns and alerts you when something deviates, regardless of whether you set a threshold.

This is useful for catching unexpected spikes that are large relative to your baseline but might not cross a fixed threshold. A service that normally costs $50 per month suddenly hitting $400 would trigger an anomaly alert even if your total budget alert is set at $5,000.

To enable it, go to AWS Cost Management and select Cost Anomaly Detection. Create a monitor for AWS services or filter by specific services, linked accounts, or cost categories. Set a subscription with a dollar threshold for what counts as worth alerting on. Zero works but will generate noise on small accounts.

What threshold to use

A common setup that works for most teams: a CloudWatch alarm at a hard ceiling you never want to cross, a Budget alert at 80 percent of your expected monthly spend, a forecasted Budget alert at 100 percent, and a Cost Anomaly Detection monitor at whatever dollar amount represents a meaningful surprise for your account size.

If your typical bill is $2,000 per month, you might set the hard ceiling at $4,000, the budget alert at $1,600, the forecast alert at $2,000, and the anomaly threshold at $200.

What alerts do not do

Billing alerts tell you that spend is high or trending high. They do not tell you which service caused it or why it happened. When an alert fires, your next step is still the investigation: Cost Explorer to see which service increased, then your Cost and Usage Report for the root cause.

If you want to skip the manual investigation, BillSpike automates the diagnosis. Upload your CUR and you get a breakdown of exactly which services drove the increase and whether it was usage, pricing, or a shift in your workload mix.

Analyze your own AWS cost spike at billspike.io