Migrate from SendGrid

Of all the providers, SendGrid is the closest to a literal find-and-replace — the send call already uses from, to, subject, and html. What changes is where your mail lives: eusend sends and stores everything on EU infrastructure, operated by an EU company, instead of a US provider.

The code change

Install the SDK with npm install @eusend_dev/sdk. The field names match; the differences are the client being an instance rather than a global singleton, and eusend returning { data, error } instead of throwing on failure.

import sgMail from '@sendgrid/mail'

sgMail.setApiKey(process.env.SENDGRID_API_KEY)

await sgMail.send({
  from: 'Acme <hello@acme.com>',
  to: 'user@example.com',
  subject: 'Welcome',
  html: '<p>Thanks for signing up.</p>',
})

import { Eusend } from '@eusend_dev/sdk'

const eusend = new Eusend(process.env.EUSEND_API_KEY)

await eusend.emails.send({
  from: 'Acme <hello@acme.com>',
  to: 'user@example.com',
  subject: 'Welcome',
  html: '<p>Thanks for signing up.</p>',
})

Field mapping

If you send over SMTP

SendGrid's SMTP setup — a literal username and your API key as the password — carries straight over. Swap the host, change the username from apikey to eusend, and make sure you're on port 465 with implicit TLS: eusend does not support STARTTLS on 587, which is SendGrid's usual default.

// Before: smtp.sendgrid.net, user "apikey", API key as password
// After: same idea, different literal username — and use implicit TLS on 465
const transport = nodemailer.createTransport({
  host: 'smtp.eusend.dev',
  port: 465,
  secure: true,
  auth: { user: 'eusend', pass: process.env.EUSEND_API_KEY },
})

Webhooks

SendGrid's Event Webhook posts arrays of event objects; eusend posts one signed event per delivery attempt. The types map cleanly:

Signature verification changes from SendGrid's ECDSA scheme to HMAC-SHA256 — simpler to implement, same guarantee. The webhook docs show the exact scheme, and you can subscribe your endpoint to only the events you handle.

What's honestly different

• Attachments carry over. SendGrid's attachments array maps almost as-is — keep content (base64) and filename, rename type → content_type and content_id stays the same for inline images (drop disposition). Up to 20 files, 10 MB combined per message.
• Bring your suppression list.eusend suppresses hard bounces and complaints automatically going forward, but it can't see your SendGrid history. Export your suppressions and keep those addresses out of your sends.
• Marketing campaigns wait. Transactional sending is open today; bulk campaigns open as the platform warms. If you use SendGrid Marketing Campaigns, plan that part for later.

Before you flip production

• Verify your sending domain and add its DKIM, SPF, and DMARC records — the Domains page generates them. Sends from unverified domains are rejected.
• Migrate against an eu_test_ API key first — test sends are accepted and tracked but never delivered — then switch to eu_live_.
• Keep SendGrid alive for a week or two after cutover so in-flight events and your suppression export have somewhere to come from.