I want to send an email with Gmail API.

Document say Gmail API require RFC2822 formatted and base64 encoded string.
So I write email contents and pass it to raw property.
But I got error: Recipient address required.

How can I fix this?

Here is my code.

const fs = require('fs');
const readline = require('readline');
const {google} = require('googleapis');

// If modifying these scopes, delete token.json.
const SCOPES = ['https://www.googleapis.com/auth/gmail.send'];
// The file token.json stores the user's access and refresh tokens, and is
// created automatically when the authorization flow completes for the first
// time.
const TOKEN_PATH = 'token.json';

// Load client secrets from a local file.
fs.readFile('credentials.json', (err, content) => {
  if (err) return console.log('Error loading client secret file:', err);
  // Authorize a client with credentials, then call the Gmail API.
  authorize(JSON.parse(content), sendGmail);

 * Create an OAuth2 client with the given credentials, and then execute the
 * given callback function.
 * @param {Object} credentials The authorization client credentials.
 * @param {function} callback The callback to call with the authorized client.
function authorize(credentials, callback) {
  const {client_secret, client_id, redirect_uris} = credentials.installed;
  const oAuth2Client = new google.auth.OAuth2(
      client_id, client_secret, redirect_uris[0]);

  // Check if we have previously stored a token.
  fs.readFile(TOKEN_PATH, (err, token) => {
    if (err) return getNewToken(oAuth2Client, callback);

 * Get and store new token after prompting for user authorization, and then
 * execute the given callback with the authorized OAuth2 client.
 * @param {google.auth.OAuth2} oAuth2Client The OAuth2 client to get token for.
 * @param {getEventsCallback} callback The callback for the authorized client.
function getNewToken(oAuth2Client, callback) {
  const authUrl = oAuth2Client.generateAuthUrl({
    access_type: 'offline',
    scope: SCOPES,
  console.log('Authorize this app by visiting this url:', authUrl);
  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
  rl.question('Enter the code from that page here: ', (code) => {
    oAuth2Client.getToken(code, (err, token) => {
      if (err) return console.error('Error retrieving access token', err);
      // Store the token to disk for later program executions
      fs.writeFile(TOKEN_PATH, JSON.stringify(token), (err) => {
        if (err) return console.error(err);
        console.log('Token stored to', TOKEN_PATH);

function sendGmail(auth){
  const makeBody = (params) => {
      params.subject = new Buffer.from(params.subject).toString("base64");
      const str = [
          'Content-Type: text/plain; charset=\"UTF-8\"\n',
          'MINE-Version: 1.0\n',
          'Content-Transfer-Encoding: 7bit\n',
          `to: ${params.to} \n`,
          `from: ${params.from} \n`,
          `subject: =?UTF-8?B?${params.subject}?= \n\n`,
      ].join(' ');
      return new Buffer.from(str).toString('base64').replace(/\+/g,'-').replace(/\//g,'_');

  const messageBody = `
  this is a test message

  const raw = makeBody({
      to : '[email protected]',
      from : '[email protected]',
      subject : 'test title',

  const gmail = google.gmail({version:'v1',auth:auth});
  }).then(res => {


Error: Recipient address required

edit : show whole code. This code still get the same error.

This is almost Google's sample and I think bug is in my code.
I add sendGnail method and edit authorize(JSON.parse(content), listLabels); to authorize(JSON.parse(content), sendGmail); ,change SCOPES ,and delete listLabels method.
(listLabels method worked fine.)
After execute listLabels method, I change SCOPES and re-create token.json.
After get Labels, I change

Here is sample https://developers.google.com/gmail/api/quickstart/nodejs?hl=ja

1 Answers

Tanaike On Best Solutions

How about this modification?


].join(' ');




  • I think that the script will work by above modification. But as one more modification point, how about modifying from 'Content-Type: text/plain; charaset=\"UTF-8\"\n', to 'Content-Type: text/plain; charset=\"UTF-8\"\n',?

If this was not the direct solution, I apologize.


I modified the function of sendGmail in your script.

Modified script:

function sendGmail(auth) {
  const makeBody = params => {
    params.subject = new Buffer.from(params.subject).toString("base64");
    const str = [
      'Content-Type: text/plain; charset="UTF-8"\n',
      "MINE-Version: 1.0\n",
      "Content-Transfer-Encoding: 7bit\n",
      `to: ${params.to} \n`,
      `from: ${params.from} \n`,
      `subject: =?UTF-8?B?${params.subject}?= \n\n`,
    ].join(""); // <--- Modified
    return new Buffer.from(str)
      .replace(/\+/g, "-")
      .replace(/\//g, "_");

  const messageBody = `
  this is a test message

  const raw = makeBody({
    to: "[email protected]",
    from: "[email protected]",
    subject: "test title",
    message: messageBody

  const gmail = google.gmail({ version: "v1", auth: auth });
      userId: "me",
      resource: {
        raw: raw
    (err, res) => { // Modified
      if (err) {