Sending emails with nodemailer on Vercel
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I couldn’t figure out why nodemailer didn’t work on Vercel, then (tldr) I found out I needed await and not a callback.
Here’s the code I had:
nodemailer
.createTransport({
host: 'smtpserver.com',
port: 465,
secure: true,
auth: {
user: import.meta.env.USER,
pass: import.meta.env.PASS,
},
})
.sendMail(
{
from: '[email protected]',
to: email,
subject,
html,
},
function (err, info) {
console.log(info)
if (err) {
console.log(err)
} else {
console.log('sent email')
}
}
)
This worked locally.
But when pushed to Vercel and it ran in a serverless function environment, the email was never sent.
Also, I never got the “sent email” message in the logs.
Nor any error.
Turns out the callback-based version of sendMail()
failed to work (due to the nature of serverless functions, I believe, they are terminated earlier and the email is never sent) and I needed to use the promise-based version, by omitting the second parameter (the callback function) to sendMail()
try {
await nodemailer
.createTransport({
host: 'smtpserver.com',
port: 465,
secure: true,
auth: {
user: import.meta.env.FASTMAIL_EMAIL,
pass: import.meta.env
.FASTMAIL_APP_SPECIFIC_PASSWORD,
},
})
.sendMail({
from: '[email protected]',
to: email,
subject,
html,
})
console.log('Email sent to ' + email)
} catch (e) {
console.error(e)
}
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