SMTP Mail Sender

smtpsendSMTP Mail Sender is an application that allows you to send messages through an SMTP server. It lets you send messages if you do not have a mail application installed, or need to send from an account that is only used for sending messages without worrying about responses. It also runs from a USB thumb drive, so you can send emails from anywhere you have access to a computer with Internet access.

  • Graphical user interface (GUI) instead of the run of the mill command line applications. UI allows customization by showing/hiding fields as necessary.
  • If you need a true command line application that does not display a user interface, I highly recommend Blat.
  • Built in address book saves you time typing email addresses, guesses and auto-completes addresses already in the address book
  • Send messages using a SMTP server from any Internet connected computer from a thumb drive
  • Supports attaching an unlimited amount of files to the message before sending
  • Sends plain text messages to minimize bandwidth used for processing the messages as they travel across the Internet.
  • Includes language support for English, French, Italian and Spanish
  • Send messages automatically from a script using command line parameters. A GUI dialog will still pop up when automatically sending the message.

Want to use SMTP Mail Sender in a different language? Check the comments below to see if someone has already provided a translation. If not, and you want to help translate to your local language, provide the translation via this template for others to use in the comments section. Have a few moments to spare? Please rate SMTP Mail Sender at the SnapFiles website!

SMTP Mail Sender requires the Microsoft .NET 2.0 Framework.
Supported/Tested Operating Systems: Windows® XP SP3, Windows 7 Home/Pro 64bit, Support on Windows® Server is limited to GUI mode, it cannot be run in Service Mode at this time.

Lost and confused? Check the frequently asked questions page.

Download Now • 47KB (v1.0.0.16)

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19 thoughts on “SMTP Mail Sender

  1. Johan Lijffijt


    Is the smtpsend log the only log? I get the following if i try office365 or gmail

    ************* gmail **********************
    3/29/2017 11:25:58 AM Enabling SSL connection
    3/29/2017 11:25:58 AM Connecting to
    3/29/2017 11:25:58 AM Sending credentials –********
    3/29/2017 11:25:58 AM Sending message to
    3/29/2017 11:26:08 AM Syntax error, command unrecognized. The server response was: << — And then the mesaage stops. What is the response ??
    ********** office 365 *********************
    3/29/2017 11:29:20 AM Enabling SSL connection
    3/29/2017 11:29:20 AM Connecting to
    3/29/2017 11:29:20 AM Sending credentials – xx@xx.xx:********
    3/29/2017 11:29:20 AM Sending message to xx@xx.xx
    3/29/2017 11:29:20 AM Failure sending mail. << — Nothing is said what kind of failure. What is the failure ?

    1. Joey HazlettJoey Hazlett Post author

      Hi Johan,

      There aren’t any more log files, this is the only one. Those error messages you are receiving are coming directly from the mail server. The application just writes the error message to the file along with the time stamp. For Gmail, please try port 587 instead of 465. Gmail expects the full transaction to be encrypted on port 465, but it uses a feature called STARTTLS on 587 to accept email. SMTPMailSender uses some built-in .NET functions that do not fully support encryption of the entire connection, so each command is encrypted instead of sending plain text over a completely secure tunnel. Due to that, Gmail is expecting plain text and receiving an encrypted command.

      I do not have any experience with Office 365. The first thing I’d try is to just disable SSL. I agree it’s hard to troubleshoot further when the remote server gives such a vague error, but there’s not much more SMTPMailSender can do other than report what it was told happened. I’m just speculating here, but is it possible that you’d need to enable SMTP access for your O365 account? Some webmail services do not allow submission of messages from remote hosts without prior authorization, to combat spamming.

      Hopefully my thoughts will help you get SMTPMailSender working in your environment.

  2. Geoff

    I can use it fine with my ISP smtp but doesn’t seem compatible with Gmail. I’ve tried it with 3 gmail accounts and it doesn’t send, gives error saying “syntax error: unrecoqnized command” in the log.

    1. Geoff

      I’ve been using port 465 which Google says to use with SSL. So instead I gave 587 a try, and it worked. I’ve tried 465 using separate ISPs too. Perhaps its being blocked. Thanks for making such a useful tool, much appreciated.

  3. Jude

    This is a great software. Please when will you include the HTML formatted body functionality?

    1. Joey HazlettJoey Hazlett Post author


      There is no immediate plan to include HTML formatted body functionality. It is a simple tool for Windows systems that was designed to send one-off emails, mostly for reporting when processes complete. If you need capability such as HTML formatting, I suggest moving up to a standard email client like Mozilla Thunderbird. There are portable versions available, which will let you run it from a thumb drive, replicating most of the features in SMTP Mail Sender and then some.


  4. JDough

    Hey thank you very much!
    Hal9000 has a great suggestion.

    I’d like to add, can we use encryption inside or outside this fine app so we can sidestep any looking on my gmail?
    IF so how?

    Again thank you muchly!

    1. Joey HazlettJoey Hazlett Post author


      In regards to Hal9000’s suggestion, there are CC and BCC fields available for use in SMTP Mail Sender, and have been since version If you do not see these in your version, you may need to download the latest version from this page.

      As for encryption, you can enable SSL, but that only encrypts the traffic between your computer and the Gmail servers. Once it has completed that step, you have no further control over who does or does not see the message, that’s under the control of the email provider.

  5. Jason

    Hi All

    Was just wondering if i can call this app through a batch file to populate some fields and send

  6. Gordie Brown

    What would really round it off would be a return code confirming a send or escape.

  7. Ole

    Nice little App, if only it worked for me…

    Can someone tell me, why it won’t send my emails?! I’ve tried all sorts of servers, from Hotmail, Gmail, etc, and the Emails never arrive… Does it connect to a certain IP, that my IP Blocker might be Blocking?!

    1. Joey HazlettJoey Hazlett Post author


      If you are using Gmail, you will need to configure the application to use Google’s mail servers. There are instructions available on Google’s site on how to do this.

      Your ISP may block outgoing mail on SMTP port 25. If that is the case, you will want to configure it to use port 465 and enable SSL. I’ve never tested with Hotmail, but I know that it will work with Gmail and Yahoo, as I’ve used both of those before (and still do).


  8. Mike

    It would be really cool to add HTML formatted body functionality

  9. Josue Aguilar

    Thanks Joey for all this free software your are offering.Here goes the Spanish translation

    From= De
    To= Para
    Subject= Asunto
    Message Body= Mensaje
    Attachment(s)= Adjunto
    Add= Agregar, anexo
    Open Text File=Abrir Archivo de Texto
    Insert Text File= Insertar Archivo de Texto
    Settings= Configuraciones
    Keep open after sending= Mantener abierto despues de enviar
    Send= Enviar
    Send a message= Enviar un Mensaje
    Server= Servidor
    Port= Puerto
    Secure Connection (SSL)= Conección Segura (SSL)
    Server requires authentication= Servidor Requiere autenticación
    Username= Nombre de Usuario
    Password= Clave
    Composition Font= Fuente
    About= Sobre
    Cancel= Cancelar
    OK= Ok
    Add new entry= Añadir nueva entrada
    Name= Nombre
    Address= Dirección
    Delete= Borrar
    Save= Guardar
    Address Book= Libro de Direcciones

  10. Jorge Rossiter

    Thanks for the excellent software. Here goes the Portuguese Brazilian translation:

    Message Body:=Mensagem
    Open Text File=Abrir Arquivo de Texto
    Insert Text File=Inserir Arquivo de Texto
    Keep open after sending=Manter aberto depois do envio
    Send a message=Enviar uma mensagem
    Secure Connection (SSL)=Conexão Segura (SSL)
    Server requires authentication=Servidor requer autenticação
    Composition Font:=Fonte:
    Add new entry=Adicionar nova entrada
    Address Book=Catálogo de Endereços

  11. gemmy

    Thanks a lot for the freeware that you offered and your effort given.

    The following translation is Chinese simplified:

    Message Body=内容
    Open Text File=打开文本文件
    Insert Text File=插入文本文件
    Keep open after sending=发送后保持运行
    Send a message=发送信息
    Secure Connection (SSL)=安全连接(SSL)
    Server requires authentication=服务器需要验证
    Composition Font=字体
    Add new entry=添加新项
    Address Book=通讯录

  12. Hedi

    Thanks Joey for all the free software your are offering.
    I enjoy using StoreURL and Networx every day. I am delighted.
    I hope helping you with this French translation of the SMTP Mail sender.
    I have a 10 years computers and telecoms engineering background as well as being a Quality Auditor and ISO 9001 Certifier.
    Don’t hesitate contacting me If I could be in any help for your future projects: (Auditing, Beta Testing, Analysis, etc…).

    Best Regards

    Message Body=Message
    Attachment(s)=Pièce(s) Jointe(s)
    Open Text File=Ouvrir Fichier Texte
    Insert Text File=Insérer Fichier Texte
    Keep open after sending=Laisser ouvert après envoi
    Send a message=Envoyer Message
    Secure Connection (SSL)=Connection Sécurisée (SSL)
    Server requires authentication=Le Serveur Requière Authentification
    Username=Nom d’Utilisateur
    Password=Mot de Passe
    Composition Font=Police de Composition
    About=A Propos
    Add new entry=Ajouter nouvelle Entrée
    Address Book= Répertoire d’Adresses


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