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ht-mailer is a hudson-taylor service for sending email, you can run it as a stand-alone service or use it in-process via the hudson-taylor LocalClient connector.

Key features

  • ht-mailer uses nodemailer, and can communicate with any nodemailer tranport, ie: AWS Simple Message Service, SMTP server, etc.

  • ht-mailer manages an email blacklist, and provides easy to use APIs for managing your blacklist (think unsubscribe tokens, etc).

  • ht-mailer keeps a message queue, and will retry emails if the transport is currently unavailable.

  • ht-mailer can be configured with mail templates (using handlebars notation), either plain text, html or markdown (generates both plain text and html).

  • ht-mailer currently requires a MongoDB DB handle which it uses to store blacklists and message queues. In the future this can be made pluggable.

Public API


Queue an email message to be delivered.

s.remote("mailer", "queue", msg, callback);

Skip the queue and send directly

s.remote("mailer", "send", msg, callback);

Block an email address that corresponds to token

s.remote("mailer", "blockToken", {token : <token>}, callback);

Block an email address

s.remote("mailer", "blockEmail", {email : <email>}, callback);

Unblock an email address

s.remote("mailer", "unblockEmail", {email : <email>}, callback);

Using ht-mailer as a stand-alone service.

  • copy config/example.json to config/production.json (or development.json etc) and add your config.
$> NODE_ENV=production node server.js

You can now communicate with it using the hudson-taylor client library, ie:

var s = new ht.Services();
s.connect("mail", new ht.HTTPClient("mail", "localhost", 7001));

Send a templated message to jemma:

var msg = { 
    to : [''],
    from : '',
    subject : 'Example Email {{foo}}',
    data : { foo : 123 },
    template : 'approval' // name of the template to use 
s.remote("mailer", "queue", msg, function(err, res) { 
    // Do things with the response here!  

Send a regular text/html email to one person:

var msg = { 
    to : [''],
    from : '',
    subject : 'Example email to {{name}}',
    data : { name : "Joe" }
    text : "Hi {{name}}!",
    html : "<h1>Hi {{name}}!</h1>"
s.remote("mailer", "queue", msg, function(err, res) {
    // do stuff! 

Using ht-mailer as an HT service.

ht-mailer service setup requires a config object, and a mongodb connection:

var mailer = require("ht-mailer");
var server = new require('hudson-taylor').Server();
var config; // See config documentation below 
var db; // Set up a mongodb connection here 
server.add("mailer", mailer.setup, config, db);
// Start communicating with an ht client/json-rpc 

Config options

Config is namespaced under an 'ht-mailer' key to play nicely with other services being configured together.

Example setup using SES transport, with some pre-defined templates

    'ht-mailer' : {
        port : 7001,
        tansport : {
            type : 'SES', //or SMTP, etc 
            'SES-arguments' : {
                accessKeyID : '123..',
                secretAccessKey : '456..'
        templates : {
            'welcome' : {markdown : '/var/myservice/templates/'},
            'unsubscribe' : {html : '/var/myservice/templates/unsub.html',
                             text : '/var/myservice/templates/unsub.txt'},
            'textemail' : {text : '/var/myservice/templates/boring.txt'}


All tempaltes use handlebars notation, which will be populated with the data provided to the send API.

Special keys you can use in templates, further to the data the caller provides are:

  • unsubscribeToken - This token can be passed to the unsubscribe API, which will block email being sent to this address in the future. ie:

    <a href='{{unsubscribeToken}}'>Unsubscribe here.</a>

    Note, when passing multiple email addresses in the 'to' field, the unsubscribe token will only apply to the first address in the list. I don't recommend using unsubscribeToken in an email with multiple to recipients, it doesn't make much sense.

Templates are configured via the tempaltes attribute in the config JSON, and can contain a file path for: markdown, text, html.

If type markdown is provided, it will be used to produce html AND text output.