AWS Lambda introduces tiered pricing for HAQM CloudWatch logs and additional logging destinations

Effective logging is an important part of an observability strategy when building serverless applications using AWS Lambda.

Lambda automatically captures and sends logs to HAQM CloudWatch Logs. This allows you to focus on building application logic rather than setting up logging infrastructure and allows operators to troubleshoot failures and performance issues more easily.

On May 1st, 2025, AWS announced changes to Lambda logging, which can reduce Lambda CloudWatch logging costs and make it easier and more cost-effective to use a wider range of monitoring tools. Lambda logs are now available at volume-based tiered pricing when using CloudWatch Logs Standard and Infrequent Access log classes. When generating Lambda logs at scale, you can expect an immediate cost reduction under this new pricing model. Lambda also now supports HAQM S3 and HAQM Data Firehose as additional destinations for Lambda logs, in addition to CloudWatch Logs. Lambda logs sent to S3 and Firehose are also available at volume-based tiered pricing.

This blog post covers some recent Lambda logging enhancements and describes how this change delivers a simpler, more cost-effective logging experience for Lambda.

Overview

Logging provides developers and operators with valuable data for debugging and troubleshooting application behavior, performance issues, and potential failures. It becomes even more important for serverless applications built using Lambda because of the ephemeral and stateless nature of the Lambda execution environment. Lambda’s built-in integration with CloudWatch Logs ensures that logs for every function invocation are readily available for analysis. The captured log data includes application logs generated by your Lambda function code and system logs generated by the Lambda service while running your function code. CloudWatch Logs allows you to search, filter, and analyze log data to troubleshoot issues, track metrics, and set up alerts.

Logging requirements evolve as serverless applications grow in complexity and scale, sometimes spanning hundreds or thousands of Lambda functions which generate substantial log volumes. Organizations need sophisticated logging solutions that can handle this scale while remaining cost-effective. Some scenarios—such as monitoring critical business transactions—demand real-time log analysis, while others focus on after-the-fact forensic analysis. Debug logs from development and staging environments often need high granularity, whereas you may want lower verbosity in production logs to improve the signal-to-noise ratio.

Recent Lambda logging enhancements

In recent years, Lambda and CloudWatch Logs have expanded Lambda’s logging capabilities to meet the evolving needs of serverless applications. These capabilities provide deeper insights, greater control, and more cost-effective solutions to capture, process, and consume logs to enhancing the serverless observability experience. Lambda advanced logging controls gives developers control over log generation and content. These controls allow you to capture Lambda logs in JSON structured format. You don’t have to use logging libraries and customize log levels (INFO, DEBUG, WARN, ERROR) separately for application and system logs. This helps reduce logging costs by ensuring only necessary logs are generated while maintaining appropriate visibility across different environments. For example, you can set verbose DEBUG level logging in development environments while limiting production logging to ERROR level to improve the signal-to-noise ratio and control costs.

The Infrequent Access log class for CloudWatch Logs introduced a cost-effective solution for logs that need retention but are accessed less frequently. Infrequent Access is 50% lower per GB ingestion price than the Standard log class This tailored set of capabilities allows you to reduce your logging costs while maintaining access to historical data for compliance, audit purposes, or forensic analysis.

CloudWatch Logs Live Tail is an interactive, real-time log streaming and analytics capability. Live Tail streamlines debugging and monitoring workflows; it allows you to observe log output as functions execute without navigating away from the Lambda console. This makes it easier to identify and diagnose issues during development and troubleshooting. Logs Live Tail is also available in Visual Code IDE.

Tiered pricing for Lambda logs in CloudWatch Logs

Starting today, Lambda logs sent to CloudWatch Logs are classed as Vended Logs, which are logs from specific AWS services that are available at volume tiered pricing. This replaces the previous flat rate model when using CloudWatch Logs Standard log class. For example, in the US East (N. Virginia) AWS Region, you were charged at $0.50 per GB when using Standard log class for your Lambda logs. Under the new pricing model, you are charged for sending your Lambda logs to CloudWatch Logs starting at $0.50 per GB for initial usage. As log volume increases, the price per GB automatically decreases through multiple tiers, reaching rates as low as $0.05 per GB in the lowest tier. This pricing change applies automatically to all Lambda logs sent to CloudWatch Logs, requiring no code or configuration changes from you.

Table 1: Tiered pricing for Lambda logs in CloudWatch Logs in US East (N. Virginia) Region

When generating Lambda logs at scale, you will see an immediate cost reduction under this new pricing model. For example, if you generate 60 TB of Lambda logs monthly in CloudWatch Logs, costs would decrease by 58% (from $30,000 to $12,500). The pricing tiers scale with your logging volume, ensuring that cost benefits increase as your application grows. This allows you to maintain comprehensive logging practices that previously may have been cost-prohibitive. Vended logs tiered pricing is applied on all vended logs ingested to CloudWatch and not tiered per service.

When ingesting other vended logs, such as HAQM Virtual Private Cloud flow logs and HAQM Route 53 resolver query logs, you will see larger discounts as the tiering is applied at a consolidated log ingestion volume.

New Lambda logging destinations: HAQM S3 and HAQM Data Firehose

Starting today, Lambda also supports HAQM S3 and HAQM Data Firehose as destinations for Lambda logs, in addition to CloudWatch Logs. When using S3 or Firehose as a destination, logging costs start at $0.25 per GB. The tiered pricing also applies, with rates reducing to as low as $0.05 per GB in the lowest tier. This tiering is also applied at a consolidated log ingestion volume.

Table 2:Tiered pricing for Lambda logs delivery to HAQM S3 and HAQM Data Firehose in US East (N. Virginia) Region

Direct delivery of Lambda logs to S3 provides enhanced flexibility in log management. Support for Firehose streamlines Lambda log delivery to additional destinations such as HAQM OpenSearch Service, HTTP endpoints, and third-party observability providers. This matches the established log delivery pattern used with other AWS compute services such as HAQM Elastic Container Service (HAQM ECS) and HAQM Elastic Compute Cloud (HAQM EC2).

This new capability provides significant cost benefits and streamlines log delivery to additional logging destinations, making it easier to use a wider range of monitoring tools (including CloudWatch) when building serverless applications using Lambda.

New Lambda logging destinations in action

All new and existing Lambda functions have CloudWatch Logs as the default logging destination, with S3 and Firehose as alternative choices. When you select S3 or Firehose as your logging destination, Lambda sends logs to the selected destination via a new CloudWatch Logs Delivery log class. This log class enables efficient routing but doesn’t support CloudWatch Logs Standard log class features, such as Logs Insights and Live Tail.

To set up S3 or Firehose as the destination for your Lambda logs in the Lambda console:

1. Navigate to the Lambda console, and select or create a function to set up an S3 or Firehose logging destination.
2. In the Configuration tab, select Monitoring and operations tools on the left pane.
3. Select Edit in the Logging configuration. This opens the Edit logging configuration page.
   

   Figure 1. Edit logging configuration in Lambda console

4. In the Log destination section, select HAQM S3 or HAQM Data Firehose. HAQM CloudWatch Logs is the default selection.
   

   Figure 2. Select log destination in the Edit logging configuration page

5. Under CloudWatch delivery log group, choose Create new log group or Existing log group.
6. To create a new delivery log group to send logs to S3, enter a log group name and specify the destination S3 bucket. Provide an AWS Identity and Access Management (IAM) role for CloudWatch Logs to deliver logs to S3.
   Follow similar steps to send logs to a Firehose stream.
   

   Figure 3. Create new CloudWatch delivery log group for S3

7. To use an existing delivery log group, select one from the Delivery log group. The selected delivery log group must have a configured destination (S3 or Firehose) and match the destination you selected.
   

   Figure 4. Select existing CloudWatch delivery log group for Firehose

Advanced logging controls are also available for S3 and Firehose destinations. These controls include JSON structured format selection and log level filters for both application and system logs. This gives you enhanced log management controls for easier search, filter, and analysis. You can also use AWS Command Line Interface (AWS CLI) and infrastructure as code (IaC) tools such as AWS CloudFormation and AWS Cloud Development Kit (AWS CDK) to set up Lambda logs delivery to S3 and Firehose.

Best practices

To get the most out of the changes announced today, ensure that your logging strategy is closely aligned with the requirements of your workload. For example, consider sending critical production logs to CloudWatch Logs to take advantage of its advanced real-time analytics and alerting features. You now automatically benefit from volume-based discounts through tiered pricing in CloudWatch Logs for high-volume logging scenarios. For logs that need long-term retention for historical analysis, you can use S3’s storage classes to further reduce costs. When using your existing or third-party monitoring tools, direct integration through Firehose eliminates the need for custom forwarding solutions and associated costs.

Logging cost optimization extends beyond destination selection. Monitor log volumes regularly to understand the impact of pricing tiers. Implement appropriate retention policies to prevent unnecessary storage of old logs and log sampling for high-volume debug logs. Consider using different logging strategies across development, staging, and production environments to balance observability needs with cost efficiency.

Conclusion

Tiered pricing for Lambda logs in CloudWatch Logs and support for S3 and Firehose as additional logging destinations improves Lambda application observability. You can now manage logging costs at scale and expand Lambda monitoring solutions through cost-effective, easy-to-configure integrations. Whether you’re building new serverless applications or optimizing existing ones, these enhancements help you implement comprehensive logging strategies that scale cost-effectively with your workload.

The new features announced today are available in all commercial AWS Regions where Lambda and CloudWatch Logs are available. Support for configuring log delivery to S3 and Firehose in the Lambda console is available in US East (Ohio), US East (N. Virginia), US West (Oregon), and Europe (Ireland) Regions, with additional Regions coming soon. Review the Lambda documentation and CloudWatch Logs documentation to learn more about these features and how to use them. Review the CloudWatch pricing page to learn more about how these features are priced.

For more serverless learning resources, visit Serverless Land.