Smart Compose response unexpected_errror

Question and Answers
1

Hi Community. I am trying to implement smart-compose feature. but whatever I send as request

I always get 400 bad request unexpected_error . my payload body is prompt as string

response is ,"error":{"type":"unexpected_error","message":"Something went wrong. Ple (truncated...)

2

The Smart Compose endpoint expects a JSON object with the prompt nested inside, not just a string. Your request body should be structured like this:

json 

{ 
  "prompt": "Your prompt text here"
 }

Keep in mind error 400 comes when the formatting of a request doesn’t have the expected content to go through. Common issues that cause 400 errors with Smart Compose include:

  • grant ID is required - Make sure you’re including a valid grant ID in the URL path
  • prompt is required - The prompt field must be present in the request body
  • invalid request - The request format is malformed

The endpoint URL should be:

POST /v3/grants/{grant_id}/messages/smart-compose

Make sure you’re including the required headers

  • Content-Type: application/json
  • Authorization: Bearer <NYLAS_API_KEY>

Also verify that your grant has the proper scopes - Smart Compose requires gmail.readonly for Google or Mail.Read for Microsoft .

If you’re still getting errors, check that your prompt is under 1,000 tokens as longer queries receive error messages.

3

Thank you for the information. I am sending json body but will check again . Can you also fix API playground? it is getting CORS error. I want to try there also.