Issue
When sending emails via the SendGrid Mail Send API (https://api.sendgrid.com/v3/mail/send or https://api.eu.sendgrid.com/v3/mail/send), you may encounter a validation error. This occurs when the email request contains incorrect or missing data in the JSON payload. Common causes include:
- A required field missing from the JSON payload.
- An improperly formatted email address.
- Structural issues in the Mail Send API request.
When these errors occur, SendGrid rejects the request and returns an error message. Below are some common validation errors, their causes, and potential resolutions.
Product
Twilio SendGrid Email
Resolution
Duplicate Email Addresses in Personalization Block 🔗
Error Message
Validation error(s): Each email address in the personalization block should be unique
between to, cc, and bcc. We found the first duplicate instance of [<email address>]
in the personalizations.0.cc field. for field personalizations.0
Cause
The same email address appears multiple times in the To, CC, or BCC fields, leading to duplication.
Resolution
- Ensure that no email address appears more than once in the To, CC, or BCC fields.
- Modify the request to include each recipient only once.
Missing Email Content 🔗
Error Message
Validation error(s): The content value must be a string at least one character in
length. for field content.0.value
Cause
The email request lacks content for both the HTML and plain text versions.
Resolution
Include the content object in your API request:
"content": [{
"type": "text/plain",
"value": "Test"
},
{
"type": "text/html",
"value": "Test"
}
],
Missing Email Subject 🔗
Error Message
Validation error(s): The subject is required. You can get around this requirement if
you use a template with a subject defined or if every personalization has a subject
defined. for field subject
Cause
The email request does not include a subject line.
Resolution
1. If using a dynamic template, define the subject in the SendGrid portal and include the template ID in the API request:
To define subject in the dynamic template in SendGrid portal
After specifying the subject line in the dynamic template, you need to include the template ID in the JSON body of the mail send API request. Below is a sample JSON body with th
{
"personalizations": [
{
"to": [
{
"email": "John@gmail.com",
"name": "Testing gmail"
}
]
}
],
"from": {
"email": "John.doe@ryanj.online",
"name": "John"
},
"reply_to": {
"email": "john.joe@ryanj.online",
"name": "John Joe"
},
"template_id": "<<template_ID>>"
}Note: To find the template ID, navigate to Dynamic Templates > Click the template and you can see the Template ID like this format "d-xxxxxxxxxx".
2. If not using a dynamic template, manually include the subject line in the API request:.
{
"personalizations": [
{
"to": [
{
"email": "sendgridtesting@gmail.com"
}
]
}
],
"from": {
"email": "john.Doe@ryanj.online",
"name": "John Doe"
},
"subject": "Test Email",
"content": [
{
"type": "text/plain",
"value": "Sendgrid - Testing"
}
]
}
Incorrectly Encoded Attachment 🔗
Error Message
Validation error(s): The attachment content must be base64 encoded.
Cause
The attachment content is not properly base64 encoded.
Resolution
Convert the attachment content to base64 before including it in the request.
Example: The text
"This is an attachment test"converts to:
"VGhpcyBpcyBhbiBhdHRhY2htZW50IHRlc3Q="Use the following format in your API request:
"attachments": [
{
"content": "VGhpcyBpcyBhbiBhdHRhY2htZW50IHRlc3Q=",
"type": "text/plain",
"filename": "attachment.txt"
}
]Tip: : Customer can use this online tool to encode the attachment content to base 64.
Missing "Personalizations" Field 🔗
Error Message
Validation error(s): The personalizations field is required and must have at least one
personalization. for field personalizations
Cause
This error occurs when the personalizations field in your JSON payload is either missing or empty. This field is mandatory and must contain at least one personalization object.
Resolution
To fix this issue, ensure that the personalizations field is included in your JSON and contains at least one valid personalization object.
For more details on how to structure the personalizations array correctly, refer to this documentation: SendGrid Personalizations.
Missing "From" Address 🔗
Error Message
Validation error(s): The from object must be provided for every email send.
It is an object that requires the email parameter, but may also contain a
name parameter. e.g. {"email" : "example@example.com"} or
{"email" : "example@example.com", "name" : "Example Recipient"}. for field from.email
Cause
The "From" field is missing in the API request.
Resolution
Include the "From" object in your API request:
"from": {
"email": "John.doe@example.com",
"name": "John Doe"
}
Additional Information
Validation errors occur when required fields are missing or incorrectly formatted in an email request. By following the resolutions above, you can ensure smooth email delivery through SendGrid. If issues persist, refer to the official SendGrid Documentation for further guidance.