How to implement certificate type authentications in lambda function

You can store the client certificate in a place like Secrets Manager. In your Lambda function, you can make a GetSecret API call outside the main handler function to store the value in memory or save it under /tmp directory for subsequent invocations for the Lambda instance. The rest will depend on how you reference the mTLS certificate from your HTTP client package for your runtime.

• Securely retrieving secrets with AWS Lambda