How to use Postman to hit AWS Comprehend Endpoint



I have a custom classifierDocument endpoint that has been configured in AWS Comprehend and is ready for real time analysis and works well. I am now trying to hit that endpoint with Postman, but i keep getting an error. Is my url incorrect or one of my headers? The error and postman configs are as follows:

Postman Config:

AWS Signature
AccessKey: <AK>
SecretKey: <SK>
AWS Region: us-east-1
Service Name: comprehend:ClassifyDocument

Auth: <stuff>
X-AMZ-Content-SHA256: <stuff>
X-AMZ-Date: <stuff>
Content-Type: application/json
Host: <stuff>
PostmanToken: <stuff>
User Agent: <stuff>
Accept: all
AcceptEncoding: gzip, deflate, br
Connection: keep alive

"Text": "Emotional Intelligence (EQ), popularized by best-selling author Daniel Goleman has been validated with multiple research studies to be a key differentiator in work performance. Emotions",
"EndpointArn": "arn:aws:comprehend:us-east-1:[stuff]:document-classifier-endpoint/pravsFirstEnd"

Text Response Error:
<Message>Unable to determine service/operation name to be authorized</Message>

Json Response Error:
"Output": {
"__type": ""
"Version": "1.0"

asked 4 years ago2494 views
1 Answer


Referred to an older post/forum made by ForzenCoder(RestAPI with Comprehend) and saw what was missing. Note to to future peeps running into this issue.

Changes/Additions Made:
Service - comprehend
X-Amz-Target - Comprehend_20171127.ClassifyDocument
Content-Type - application/x-amz-json-1.1

Getting proper response now. All is well.

answered 4 years ago

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