The Resend alternative that keeps your code

Migrating from Resend

With the Node.js SDK (npm install mailcheer), two lines change: the import (import { Mailcheer } from "mailcheer") and the constructor. Your resend.emails.send({ from, to, subject, html }) calls stay as they are and still resolve to { data, error }.

With plain HTTP: change the URL (https://mailcheer.com/api/v1/emails) and the Authorization header. One prerequisite: the sending domain must be verified in your workspace — until it is, each send returns 422 unverified_from_domain.

What differs: headers — Mailcheer drops List-Unsubscribe; pass unsubscribe_url and Mailcheer writes both unsubscribe headers automatically. attachments[].path (a URL to fetch) is refused with a 422; send the file as base64 in content. Webhooks are signed by one Mailcheer-Signature header (HMAC-SHA256) instead of Svix's three headers.

Adaptations: to schedule a send, use the campaign scheduler in the interface. A React template converts to HTML before sending (@react-email/render or renderToStaticMarkup) — pass the result in html. No topic_id: target with your workspace's segments and tags. Bulk sends go through campaigns or automations. A call with neither html nor text returns 422; test res.ok rather than status === 200 (Mailcheer answers 202).

Ramp-up: a new workspace sends at most 1,000 emails per rolling 24 hours until it is verified, which happens automatically at its first send. Make a small first send before moving all your traffic.