Error when trying to send transactional email from template using sendGrid - node.js

Question

I'm trying to send a transactional email via node using sendGrid. Below is an example of my code.
const subject = 'Email subject';
const templateId = 'templateId';
const sg = require('sendgrid')(secret);
const request = sg.emptyRequest({
method: 'POST',
path: '/v3/mail/send',
body: {
"personalizations": [
{
"bcc": userEmails,
"substitutions": {
"-userName-": userDetails.name,
"-productPrice-": productDetails.price,
"-productUrl-": productDetails.url,
"-productPercentageDrop-": productDetails.percentageDrop,
"-productName-": productDetails.name,
"-productOriginalPrice-": productDetails.origPrice,
"-productDroppedPrice-": productDetails.dropPrice,
"-productImageUrl-": productDetails.imageUrl
},
"subject": subject.substring(0, 75)
}
],
"from": {
"email": "myemail",
"name": "myname"
},
"content": [
{
"type": "text/html"
}
],
"template_id": templateId
}
});
sg.API(request, function (error, response) {
if (error) {
console.log('Error response received');
}
console.log(response.body.errors);
});
But every time I run the code I get the following error message.
400
message: 'Bad Request', field: null, help: null
Which isn't really that helpful when trying to find out why its erroring.
Body JSON being sent:
{
"host":"",
"method":"POST",
"path":"/v3/mail/send",
"headers":{
},
"body":{
"personalizations":[
{
"bcc":[
{
"email":"name1#hotmail.com",
"name":"name1"
},
{
"email":"name2#hotmail.com",
"name":"name2"
}
],
"substitutions":{
"-productPrice-":189.5,
"-productUrl-":"http://www.tesco.com/direct/humax-fvp-4000t500-m-smart-freeview-play-hd-digital-tv-recorder-with-wi-fi-500gb/483-1785.prd",
"-productName-":"Tesco direct: Humax FVP-4000T/500 (M) Smart Freeview Play HD Digital TV Recorder with Wi-Fi - 500GB"
},
"subject":"Product Tesco direct: Humax FVP-4000T/500 (M) Smart Freeview Play HD Digita"
}
],
"from":{
"email":"email#pricetracker.io",
"name":"Pricetracker"
},
"content":[
{
"type":"text/html"
}
],
"template_id":"XXXXXX"
},
"queryParams":{
},
"test":false,
"port":""
}

Answer 1

don't know if this could still be helpful for you, but I've had some similar issues when using substitutions with Sendgrid. I'm using the sendgrid-php library, but internally it sends the same format. What I found was that all substitution values should be converted to string. For instance your value for productPrice should be like this:
"-productPrice-": "189.5",
With quotes. In my case I had integers, and when I converted them to strings, all worked correctly.

Answer 2

If you are not passing string value to the template file then SendGrid will give you
{"errors":[{"message":"Bad Request","field":null,"help":null}]}
Convert your all non-string value to string before sending to the template file.

Answer 3

I got same issue, then I fix using this below syntax, change only you message format.
"value": "'.html_entity_decode((str_replace('"',"'",$message))).'"