Send bulk emails using sendgrid api in php

This is an example of how to send bulk emails to the users in chunks.

$users = DB::get("SELECT * FROM user;");

$chunks = array_chunk($users, 1000);
foreach ($chunks as $chunk) {
  $personalizations = [];
  foreach ($chunk as $user) {
    $personalizations[] = [
      "to"=> ["email"=>$user['email']],
      "substitutions"=>[
        "{name}" =>$user['name'],
      ]
    ];
  }

  $args = [
    "personalizations"=>$personalizations,
    "from"=>[
      "name"=>"Sender Name",
      "email"=>"sender@example.com"
    ],
    "subject": "Example",
    "content": [
      {
        "type": "text/plain",
        "value": "Hello {name},"
      },
      {
        "type": "text/html",
        "value": "Hello {name}"
      }
    ]
  ];

  HttpPost(
    'https://api.sendgrid.com/v3/mail/send',
    $args,
    [
      "header"=> [
        "Authorization"=> "Bearer $api_code"
      ]
    ]
  );
}

More:
https://docs.sendgrid.com/ui/sending-email/substitution-and-section-tags#simple-name-substitution