why is queryStringParameters is null - amazon-web-services

Question

When i send a get request to the aws gateway with https://xxxamazonaws.com/prod/list?555
i wanted to capture the trailing "555" in the request url.
i tried using the logic below(python) in lambda but unfortunately i cannot capture the "555" part since queryStringParameters is null
productid=list(event['queryStringParameters'].keys())[0]
The event doesnt have any trace of the product id
{
"resource": "/list",
"path": "/list",
"httpMethod": "GET",
"headers": null,
"multiValueHeaders": null,
"queryStringParameters": null,
"multiValueQueryStringParameters": null,
"pathParameters": null,
"stageVariables": null,
"requestContext": {
"resourceId": "aazo5x",
"resourcePath": "/list",
"httpMethod": "GET",
"extendedRequestId": "brfc9EVHvHcF5WQ=",
"requestTime": "16/Nov/2022:05:46:07 +0000",
"path": "/list",
"accountId": "1234",
"protocol": "HTTP/1.1",
"stage": "test-invoke-stage",
"domainPrefix": "testPrefix",
"requestTimeEpoch": 1668577567573,
"requestId": "17da8762-6369-4f54-9c67-dddd68795",
"identity": {
"cognitoIdentityPoolId": null,
"cognitoIdentityId": null,
"apiKey": "test-invoke-api-key",
"principalOrgId": null,
"cognitoAuthenticationType": null,
"userArn": "arn:aws:iam::12345:user/12345",
"apiKeyId": "test-invoke-api-key-id",
"userAgent": "aws-internal/3 aws-sdk-java/1.12.302 Linux/5.10.144-111.639.amzn2int.x86_64 OpenJDK_64-Bit_Server_VM/25.352-b08 java/1.8.0_352 vendor/Oracle_Corporation cfg/retry-mode/standard",
"accountId": "12345",
"caller": "AIDAYQECU",
"sourceIp": "test-invoke-source-ip",
"accessKey": "AIDAYQECU",
"cognitoAuthenticationProvider": null,
"user": "AADSWSCCO3L4N"
},
"domainName": "testPrefix.testDomainName",
"apiId": "31u00z1fz9"
},
"body": null,
"isBase64Encoded": false
}
Is it possible to capture just the trailing number after ? -> "555"
without using query string format ?key=value