Architect Data Action 403 Forbidden when calling Lambda from Genesys Cloud

Architect & Flows
1

Hey everyone.

I’m trying to call an AWS Lambda function directly from a Genesys Cloud Architect flow using the Invoke Lambda Data Action. The goal is to update our local WFM adherence table when an agent takes a break. I’ve got the flow set up and the endpoint configured, but I keep hitting a wall with permissions.

Here is the configuration in Architect:

Action: Invoke Lambda
Endpoint: https://lambda.us-east-1.amazonaws.com/2015-03-31/functions/arn:aws:lambda:us-east-1:123456789012:function:wfm-update/invocations
Method: POST

When the flow runs, it returns a 403 Forbidden error. The response body looks like this:

{ 
 "message": "User: arn:aws:sts::123456789012:assumed-role/GenesysCloudExecutionRole/i-0123456789abcdef0 is not authorized to perform: lambda:InvokeFunction on resource: arn:aws:lambda:us-east-1:123456789012:function:wfm-update"
}

I’ve attached a policy to the execution role that allows lambda:InvokeFunction on that specific ARN, but it still fails. I’m not sure if Genesys Cloud uses a specific IAM role for outbound calls or if I need to add a resource-based policy on the Lambda function itself.

Any ideas on what I’m missing? I’ve checked the endpoint URL multiple times and it matches the docs.

2

Right, that 403 is almost certainly coming from the IAM policy on the Lambda side, not Genesys itself. When you invoke a Lambda directly via the AWS API endpoint like that, you aren’t using the Genesys Cloud integration wrapper. That means Genesys is just making a standard HTTPS POST request to AWS. AWS sees an unauthenticated or improperly signed request and blocks it immediately.

The “Invoke Lambda” data action in Architect is designed to work with the Genesys Cloud Lambda integration, which handles the authentication handshake for you. If you’re trying to hit the raw lambda.us-east-1.amazonaws.com endpoint, you need to sign the request with AWS Signature Version 4. The Architect data action doesn’t do that automatically for raw endpoints.

You have two real options here. The first is to use the Genesys Cloud Lambda integration properly. You register the Lambda in Genesys Cloud under Admin > Integrations > AWS Lambda. Then, in Architect, you don’t point it at the AWS URL. You point it at the integration ID.

The second option, if you must call the raw endpoint (which I’d advise against for security reasons unless you have a very specific reason), is to use an HTTP Post action instead and manually construct the signed request. That’s a nightmare to maintain in Architect.

Let’s assume you want the clean path: using the Genesys Cloud integration. Here is how the configuration should look.

  1. Go to Admin > Integrations > AWS Lambda.
  2. Create a new integration. You’ll need your AWS Access Key ID and Secret Access Key. Make sure the IAM user associated with these keys has permission to invoke the specific Lambda function. The policy should look something like this:
{
 "Version": "2012-10-17",
 "Statement": [
 {
 "Effect": "Allow",
 "Action": [
 "lambda:InvokeFunction"
 ],
 "Resource": "arn:aws:lambda:us-east-1:YOUR_ACCOUNT_ID:function:YOUR_FUNCTION_NAME"
 }
 ]
}
  1. Once the integration is active, note the Integration ID.
  2. In Architect, add an “Invoke Lambda” action.
  3. Do not enter the AWS URL. Instead, select the integration you just created from the dropdown.
  4. Map your payload. The payload sent to the Lambda is the JSON object you define in the action.

Here is a sample JSON payload you might send to update that WFM table:

{
 "agentId": "{{agent.id}}",
 "actionType": "break",
 "timestamp": "{{system.currentDateTime}}",
 "durationSeconds": 0
}

If you are still getting 403s after setting up the integration correctly, check the CloudWatch logs for the Lambda function. It might be failing on the AWS side due to a resource policy that doesn’t allow the Genesys Cloud IP ranges, though usually, the IAM user permissions are the culprit.

Also, double-check that the IAM user has logs:CreateLogGroup and logs:CreateLogStream permissions, otherwise the Lambda might fail to start up properly and return a vague error.

One more thing to watch out for. If your Lambda function is in a VPC, you need to make sure the Genesys Cloud integration can reach it. Genesys Cloud uses specific IP ranges. You might need to add a NAT gateway or ensure the Lambda has public access if it’s not strictly internal. But for a simple WFM update, a public Lambda with a restrictive IAM policy is usually the easiest start.

Don’t try to use the raw AWS endpoint in Architect. It’s asking for trouble. Stick to the integration wrapper.