# Custom data sources
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For logs that are not covered by AWS service or third-party integrations, CloudWatch pipelines can process custom logs stored in CloudWatch Logs or Amazon S3 buckets. Custom sources accommodate unique organizational requirements:
+ **Application-specific logs** – Custom application telemetry from Amazon EC2 instances with specialized logging formats
+ **File-based ingestion** – Amazon S3-based log files from legacy systems or batch processing workflows
+ **Serverless integration** – Lambda function logs and custom serverless application telemetry

For more details, see [Custom log data from CloudWatch Logs or an Amazon S3 bucket](ingestion-custom-data-sources.md).