Create an AWS Lambda function that runs in the same VPC as the API application. Configure the function as an EventBridge target. Use the function to send events to the API.

Create an internet-facing Application Load Balancer ALB in front of the API application. Associate a security group with rules that block access from all external sources except for EventBridge. Configure the ALB as an EventBridge target.

Create an internet-facing Network Load Balancer NLB in front of the API application. Associate a security group with rules that block access from all external sources except for EventBridge. Configure the NLB as an EventBridge target.

Use the application API endpoint in the VPC as a target for EventBridge. Send events directly to the application API endpoint from EventBridge.