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Send

Send a batch of emails using the default context. 
func (s *BatchSvcImpl) Send(params []*SendEmailRequest) (*BatchEmailResponse, error)

​
Parameters

​
params
[]*SendEmailRequest
required
Array of email requests to send in batch. Each request should follow the same structure as a single email send request.

​
Returns

Returns a *BatchEmailResponse containing the results of the batch send operation.

​
Example

emails := []*resend.SendEmailRequest{
  {
    From:    "[email protected]",
    To:      []string{"[email protected]"},
    Subject: "Welcome User 1",
    Html:    "<p>Welcome to our service!</p>",
  },
  {
    From:    "[email protected]",
    To:      []string{"[email protected]"},
    Subject: "Welcome User 2",
    Html:    "<p>Welcome to our service!</p>",
  },
}

response, err := client.Batch.Send(emails)
if err != nil {
  panic(err)
}

​
SendWithContext

Send a batch of emails with a custom context. 
func (s *BatchSvcImpl) SendWithContext(ctx context.Context, params []*SendEmailRequest) (*BatchEmailResponse, error)

​
Parameters

​
ctx
context.Context
required
Context for the request, useful for timeouts and cancellation.
​
params
[]*SendEmailRequest
required
Array of email requests to send in batch.

​
Returns

Returns a *BatchEmailResponse containing the results of the batch send operation.

​
Example

ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()

emails := []*resend.SendEmailRequest{
  {
    From:    "[email protected]",
    To:      []string{"[email protected]"},
    Subject: "Welcome User 1",
    Html:    "<p>Welcome to our service!</p>",
  },
}

response, err := client.Batch.SendWithContext(ctx, emails)
if err != nil {
  panic(err)
}

​
SendWithOptions

Send a batch of emails with custom context and options. 
func (s *BatchSvcImpl) SendWithOptions(ctx context.Context, params []*SendEmailRequest, options *BatchSendEmailOptions) (*BatchEmailResponse, error)

​
Parameters

​
ctx
context.Context
required
Context for the request, useful for timeouts and cancellation.
​
params
[]*SendEmailRequest
required
Array of email requests to send in batch.
​
options
*BatchSendEmailOptions
Additional options for the batch send operation.

​
Returns

Returns a *BatchEmailResponse containing the results of the batch send operation.

​
Example

options := &resend.BatchSendEmailOptions{
  IdempotencyKey:  "unique-key-123",
  BatchValidation: resend.BatchValidationPermissive,
}

emails := []*resend.SendEmailRequest{
  {
    From:    "[email protected]",
    To:      []string{"[email protected]"},
    Subject: "Welcome",
    Html:    "<p>Welcome!</p>",
  },
}

response, err := client.Batch.SendWithOptions(context.Background(), emails, options)
if err != nil {
  panic(err)
}

​
Types

​
BatchSendEmailOptions

Additional options for batch email sending. 
type BatchSendEmailOptions struct {
  IdempotencyKey  string              `json:"idempotency_key,omitempty"`
  BatchValidation BatchValidationMode `json:"-"`
}
​
IdempotencyKey
string
Unique key to ensure idempotent requests. Prevents duplicate sends if the same key is used.
​
BatchValidation
BatchValidationMode
Controls the validation behavior for batch emails. Can be BatchValidationStrict (default) or BatchValidationPermissive.
  • BatchValidationStrict: Only sends the batch if all emails are valid
  • BatchValidationPermissive: Processes all emails, allowing partial success

​
BatchValidationMode

Validation mode constants for batch email sending. 
type BatchValidationMode string

const (
  BatchValidationStrict     BatchValidationMode = "strict"
  BatchValidationPermissive BatchValidationMode = "permissive"
)
​
BatchValidationStrict
BatchValidationMode
Only sends the batch if all emails are valid. This is the default mode.
​
BatchValidationPermissive
BatchValidationMode
Processes all emails, allowing partial success. Failed emails will be listed in the Errors field of the response.

​
BatchEmailResponse

Response from a batch email send operation. 
type BatchEmailResponse struct {
  Data   []SendEmailResponse `json:"data"`
  Errors []BatchError        `json:"errors,omitempty"`
}
​
Data
[]SendEmailResponse
Array of successful email send responses, each containing the email ID.
​
Errors
[]BatchError
Array of errors for specific emails in the batch when using permissive validation mode.

​
BatchError

Represents an error for a specific email in a batch request. 
type BatchError struct {
  Index   int    `json:"index"`
  Message string `json:"message"`
}
​
Index
int
The index of the failed email in the original request array.
​
Message
string
Error message describing why the email failed.

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