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Connect AWS CloudWatch to query custom usage metrics, such as S3 storage size, request counts, CPU usage, or queue depth. Costory pairs these with billing data so you can build unit economics. On Add integration, the AWS tile is CloudWatch metrics / Parquet files from S3. Choose CloudWatch on that tile. For Parquet files, see S3 metrics.
Add integration AWS choice between CloudWatch and S3 metrics

AWS External metric choice: CloudWatch or S3 metrics

Connect AWS CloudWatch form with IAM policy JSON, Role ARN, and AWS region

Connect AWS CloudWatch: read policy on the left, Role ARN and region on the right

Lower half of Connect AWS CloudWatch with the custom trust policy, Role ARN, region, Validate, and Save connection

CloudWatch connect screen: IAM trust policy and Validate before Save connection

1

Create the CloudWatch read policy

In IAM, create a customer managed policy from this JSON. Attach it to the role after you set up trust.
2

Create the trust policy

Create or edit an IAM role Costory can assume. Use the same web identity trust as AWS billing: federated access for Costory’s GCP service account. Copy the trust policy from the Costory connect screen, then attach the CloudWatch read policy to that role.
3

Open the AWS tile

Go to Integrations, click + Add integration, then under External metric choose AWS. Pick CloudWatch (not S3 metrics).
4

Enter connection details

Fill Connection name, Role ARN, and AWS region. Click Validate, then Save connection.
5

Query in Advanced Explorer

Click Explore your data, switch to Advanced, then + Add Metric. Open integrations and pick the CloudWatch source. See Query after you connect.
Save connection stays disabled until validation succeeds.

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Example CloudWatch metrics

After you connect, pick a CloudWatch metric in Advanced Explorer. One common series is total bytes per S3 bucket (AWS/S3 BucketSizeBytes).
CloudWatch query selecting SUM of BucketSizeBytes grouped by BucketName

CloudWatch metric query for S3 bucket size

Other series teams query:
  • Total bytes per S3 bucket (AWS/S3 BucketSizeBytes)
  • Request counts on API Gateway, ALB, or CloudFront (AWS/ApiGateway, AWS/ApplicationELB, AWS/CloudFront)
  • Average CPU or memory by service, cluster, or Auto Scaling group (AWS/EC2, AWS/ECS, AWS/EKS)
  • SQS queue length and messages sent or received (AWS/SQS)
  • RDS or Aurora connections, CPU, and IOPS (AWS/RDS)
CloudWatch usage metric visualized in Costory

CloudWatch metric series in Costory after the query returns data

S3 metrics

Connect Parquet files from S3 on the same AWS tile.

Metrics Correlation

Query external metrics in Advanced Explorer.

Unit Economics

Divide cloud cost by a CloudWatch metric.

AWS Billing

Connect CUR 2.0 with the same federated IAM trust.
Last modified on August 20, 2026