A developer built a serverless application that uses API Gateway, Lambda functions, and Route 53. During testing the developer sees errors but cannot immediately find the root cause. To search across all application logs with the least operational overhead, what should the developer do?

The correct answer is to enable CloudWatch Logs for API Gateway stages with JSON format and use CloudWatch Logs Insights. This is the most efficient solution for searching and analyzing logs across all application services with the least operational overhead. CloudWatch Logs Insights is specifically designed for interactive log analysis and can query logs from various AWS services, including Lambda and API Gateway, directly within CloudWatch. Enabling JSON format for API Gateway logs makes them easily parsable for structured queries. The other options are less suitable: Publishing logs to CloudWatch and querying with Athena is possible but adds more steps and potentially higher operational overhead than Logs Insights for real-time analysis. Route 53 health checks and CloudTrail are for monitoring service availability and API calls, respectively, not for application-level logs or comprehensive root cause analysis of application errors. Kinesis Data Firehose to S3 and then OpenSearch Service is a robust solution for large-scale log aggregation and analysis but involves more setup and operational overhead than simply using CloudWatch Logs Insights for this scenario.