Api Gateway body validation [Unknown error parsing request body]

Question

Hello,
We have an Api Gateway REST Api deployed using SAM and we use the body validation with models that worked fine until we encountered the case where a customer write with specials characters.
The resource is a PUT /v1/{id}/label with a Lambda integration and a custom authorizer (that succeed).
The body validation use the following model:

```
{
  "required" : [ "label" ],
  "type" : "object",
  "properties" : {
    "label" : {
      "maxLength" : 50,
      "minLength" : 1,
      "type" : "string",
      "description" : "The new label of the vehicle."
    },
    "group" : {
      "maxLength" : 50,
      "minLength" : 1,
      "type" : "string",
      "description" : "The new group of the vehicle"
    }
  }
}
```

But when making the request with special characters like this: `{"label":"TOS056","group":"Чарвак"}`,  the validation fails with the following `$context.error.validationErrorString: "[Unknown error parsing request body]"`

I have not found anything in [Amazon API Gateway important notes](https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-known-issues.html) about some characters being not allowed in the body.

The request is made with axios that automatically add the following headers:

```
      Accept: application/json, text/plain, */*
      Content-Type: application/json
      Content-Length: 35
```

How can I know what the unknown parsing error is, or is there a list of allowed characters that I have not seen ?

Deeksha · Accepted Answer

Verify that the request body is correctly encoded as UTF-8. JSON is typically UTF-8 encoded by default, but you should ensure that your client (Axios in this case) is correctly encoding the payload.

Charset Declaration: Explicitly specify charset=utf-8 in the Content-Type header to ensure the server correctly interprets the character encoding.

Enable Detailed CloudWatch Logs:

Go to the API Gateway console.
Select your API and then the Stages section.
Choose your stage, and under the Logs/Tracing tab, enable detailed CloudWatch logging.
Check CloudWatch logs for detailed error messages that might provide more insight into the validation failure.

Api Gateway body validation [Unknown error parsing request body]

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