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NB! This version of MailParser is incompatible with pre 0.2.0, do not upgrade from 0.1.x without updating your code, the API is totally different.

MailParser is an asynchronous and non-blocking parser for node.js to parse mime encoded e-mail messages. Handles even large attachments with ease - attachments can be parsed in chunks and streamed if needed.

MailParser parses raw source of e-mail messages into a structured object.

No need to worry about charsets or decoding quoted-printable or base64 data, MailParser (with the help of node-iconv) does all of it for you. All the textual output from MailParser (subject line, addressee names, message body) is always UTF-8.

Live Demo

You can test this module in action here:


npm install mailparser


Require MailParser module

var MailParser = require("mailparser").MailParser;

Create a new MailParser object

var mailparser = new MailParser([options]);

Options parameter is an object with the following properties:

  • debug - if set to true print all incoming lines to console
  • streamAttachments - if set to true, stream attachments instead of including them
  • unescapeSMTP - if set to true replace double dots in the beginning of the file
  • defaultCharset - the default charset for text/plain, text/html content, if not set reverts to Latin-1

MailParser object is a writable Stream - you can pipe directly files to it or you can send chunks with mailparser.write

When the parsing ends an 'end' event is emitted which has an object parameter with parsed e-mail structure.

mailparser.on("end", function(mail){
    mail; // object structure for parsed e-mail

Parsed mail object

  • headers - an array of headers, in the form of - [{key: "key", value: "value"}]
  • from - an array of parsed From addresses - [{address:'',name:'Sender Name'}] (should be only one though)
  • to - an array of parsed To addresses
  • cc - an array of parsed Cc addresses
  • subject - the subject line
  • text - text body
  • html - html body
  • alternatives - an array of alternative bodies in addition to the default html and text - [{contentType:"text/plain", content: "..."}]
  • attachments - an array of attachments

Decode a simple e-mail

This example decodes an e-mail from a string

var MailParser = require("mailparser").MailParser,
    mailparser = new MailParser();

var email = "From: 'Sender Name' <>\r\n"+
            "To: 'Receiver Name' <>\r\n"+
            "Subject: Hello world!\r\n"+
            "How are you today?";

// setup an event listener when the parsing finishes
mailparser.on("end", function(mail_object){
    console.log("From:", mail_object.from); //[{address:'',name:'Sender Name'}]
    console.log("Subject:", mail_object.subject); // Hello world!
    console.log("Text body:", mail_object.text); // How are you today?

// send the email source to the parser

Pipe file to MailParser

This example pipes a readableStream file to MailParser

var MailParser = require("mailparser").MailParser,
    mailparser = new MailParser(),
    fs = require("fs");

mailparser.on("end", function(mail_object){
    console.log("Subject:", mail_object.subject);



By default any attachment found from the e-mail will be included fully in the final mail structure object as Buffer objects. With large files this might not be desirable so optionally it is possible to redirect the attachments to a Stream and keep only the metadata about the file in the mail structure.

mailparser.on("end", function(mail_object){
    for(var i=0; i<mail_object.attachments.length; i++){

Default behavior

By default attachments will be included in the attachment objects as Buffers.

attachments = [{
    contentType: 'image/png',
    fileName: 'image.png',
    contentDisposition: 'attachment',
    contentId: '5.1321281380971@localhost',
    transferEncoding: 'base64',
    length: 126,
    generatedFileName: 'image.png',
    checksum: 'e4cef4c6e26037bcf8166905207ea09b',
    content: <Buffer ...>

The property generatedFileName is usually the same as fileName but if several different attachments with the same name exist or there is no fileName set, an unique name is generated.

Property content is always a Buffer object (or SlowBuffer on some occasions)

Attachment streaming

Attachment streaming can be used when providing an optional options parameter to the MailParser constructor.

var mp = new MailParser({
    streamAttachments: true

This way there will be no content property on final attachment objects (but the other fields will remain).

To catch the streams you should listen for attachment events on the MailParser object. The parameter provided includes file information (contentType, fileName, contentId) and a readable Stream object stream.

var mp = new MailParser({
    streamAttachments: true

mp.on("attachment", function(attachment){
    var output = fs.createWriteStream(attachment.fileName);;

In this case the fileName parameter is equal to generatedFileName property on the main attachment object, you match attachment streams to the main attachment objects through these values.

Testing attachment integrity

Attachment objects include length property which is the length of the attachment in bytes and checksum property which is md5 hash of the file.



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