Sending Emails (SMTP)¶

Learn how to send emails from your Free Pascal programs. This is useful for notifications, alerts, or any app that needs to contact users.

What You Need¶

To send emails, you need:

An email account
The SMTP server address (the mail service host)
Your login credentials
The email address to send to

Common SMTP servers:

Gmail: smtp.gmail.com (port 587)
Outlook: smtp-mail.outlook.com (port 587)
Yahoo: smtp.mail.yahoo.com (port 587)
Custom server: Ask your email provider for details

Simple Email Example¶

Here's a basic example sending an email:

program SendEmail;

{$mode objfpc}{$H+}{$J-}

uses
  Classes,
  SysUtils,
  smtpsend,
  ssl_openssl;

var
  Mail: TSMTPSend;
  MailText: TStringList;

begin
  { Create email content }
  MailText := TStringList.Create;
  try
    MailText.Add('From: your.email@gmail.com');
    MailText.Add('To: recipient@example.com');
    MailText.Add('Subject: Hello from Free Pascal!');
    MailText.Add('');
    MailText.Add('This is a test email sent from Free Pascal.');
    MailText.Add('');
    MailText.Add('Best regards,');
    MailText.Add('Your Name');

    { Create SMTP client }
    Mail := TSMTPSend.Create;
    try
      { Set server details }
      Mail.TargetHost := 'smtp.gmail.com';
      Mail.TargetPort := '587';
      Mail.Username := 'your.email@gmail.com';
      Mail.Password := 'your.app.password';  { Use app password, not regular password }
      Mail.FullSSL := False;  { Use STARTTLS }

      WriteLn('Connecting to email server...');

      { Try to send email }
      if Mail.SendToRaw('your.email@gmail.com', 'recipient@example.com', MailText) then
        WriteLn('Email sent successfully!')
      else
        WriteLn('Error: ', Mail.EnhancedStatusCode);

    finally
      Mail.Free;
    end;

  finally
    MailText.Free;
  end;

  WriteLn('Press enter to exit...');
  ReadLn;
end.

Gmail Setup (Important!)¶

If you're using Gmail, you cannot use your regular password. You need to:

Turn on 2-Step Verification in your Google Account
Create an App Password (not your regular password)
Use this app password in your code

Google Help: Create & use App Passwords

HTML Emails¶

You can send formatted emails using HTML:

program SendHTMLEmail;

{$mode objfpc}{$H+}{$J-}

uses
  Classes,
  SysUtils,
  smtpsend,
  ssl_openssl;

var
  Mail: TSMTPSend;
  MailText: TStringList;

begin
  MailText := TStringList.Create;
  try
    MailText.Add('From: your.email@gmail.com');
    MailText.Add('To: recipient@example.com');
    MailText.Add('Subject: Formatted Email');
    MailText.Add('Content-Type: text/html; charset=UTF-8');
    MailText.Add('');
    MailText.Add('<html>');
    MailText.Add('<body>');
    MailText.Add('<h1>Hello!</h1>');
    MailText.Add('<p>This is a <strong>formatted</strong> email.</p>');
    MailText.Add('<a href="https://example.com">Click here</a>');
    MailText.Add('</body>');
    MailText.Add('</html>');

    Mail := TSMTPSend.Create;
    try
      Mail.TargetHost := 'smtp.gmail.com';
      Mail.TargetPort := '587';
      Mail.Username := 'your.email@gmail.com';
      Mail.Password := 'your.app.password';
      Mail.FullSSL := False;

      WriteLn('Sending HTML email...');

      if Mail.SendToRaw('your.email@gmail.com', 'recipient@example.com', MailText) then
        WriteLn('Email sent!')
      else
        WriteLn('Error: ', Mail.EnhancedStatusCode);

    finally
      Mail.Free;
    end;

  finally
    MailText.Free;
  end;

  WriteLn('Press enter to exit...');
  ReadLn;
end.

Sending to Multiple Recipients¶

Send one email to several people:

program SendMultiple;

{$mode objfpc}{$H+}{$J-}

uses
  Classes,
  SysUtils,
  smtpsend,
  ssl_openssl;

var
  Mail: TSMTPSend;
  MailText: TStringList;
  Recipients: TStringList;

begin
  MailText := TStringList.Create;
  Recipients := TStringList.Create;

  try
    { Create email }
    MailText.Add('From: your.email@gmail.com');
    MailText.Add('Subject: Team Announcement');
    MailText.Add('');
    MailText.Add('Hello team!');
    MailText.Add('This is an announcement for everyone.');

    { Add recipients }
    Recipients.Add('person1@example.com');
    Recipients.Add('person2@example.com');
    Recipients.Add('person3@example.com');

    Mail := TSMTPSend.Create;
    try
      Mail.TargetHost := 'smtp.gmail.com';
      Mail.TargetPort := '587';
      Mail.Username := 'your.email@gmail.com';
      Mail.Password := 'your.app.password';
      Mail.FullSSL := False;

      { Send to each recipient }
      for var Recipient in Recipients do
      begin
        WriteLn('Sending to: ', Recipient);
        Mail.SendToRaw('your.email@gmail.com', Recipient, MailText);
      end;

      WriteLn('All emails sent!');

    finally
      Mail.Free;
    end;

  finally
    MailText.Free;
    Recipients.Free;
  end;

  WriteLn('Press enter to exit...');
  ReadLn;
end.

Error Handling¶

Check for problems when sending:

var
  Mail: TSMTPSend;
begin
  Mail := TSMTPSend.Create;
  try
    Mail.TargetHost := 'smtp.gmail.com';
    Mail.TargetPort := '587';
    Mail.Username := 'your.email@gmail.com';
    Mail.Password := 'your.app.password';
    Mail.FullSSL := False;

    if Mail.SendToRaw(FromAddr, ToAddr, MailText) then
    begin
      WriteLn('Success!');
    end
    else
    begin
      WriteLn('Failed to send email');
      WriteLn('Status code: ', Mail.EnhancedStatusCode);
      WriteLn('Result: ', Mail.ResultString);
    end;

  finally
    Mail.Free;
  end;
end;

Email Format Tips¶

When building emails, remember:

The header (From, To, Subject) comes first
Then a blank line
Then the body content
Blank lines in the body are just empty lines in the StringList

Security Notes¶

⚠️ Important:

Never hardcode passwords in your code
Use environment variables or config files to store credentials
Use app passwords (not your main password) for services like Gmail
Consider using email service APIs instead of SMTP for large applications

Using Environment Variables for Credentials¶

var
  username: string;
  password: string;
begin
  { Get from environment variables instead of hardcoding }
  username := GetEnvironmentVariable('EMAIL_USER');
  password := GetEnvironmentVariable('EMAIL_PASS');

  Mail.Username := username;
  Mail.Password := password;
end;

Common Issues¶

Connection timeout - Check your server address and port
Authentication failed - Check username and password (use app password for Gmail)
Can't resolve host - Check internet connection and server name
SSL certificate errors - Some servers may need different SSL settings

Next Steps¶

Try sending a simple email to yourself
Add email notifications to a program
Create a newsletter system using email
Implement email verification in your app