Skills Development Configure SMTP Mailer Settings

Configure SMTP Mailer Settings

v20260825
webiny-mailer-smtp
This guide details how to configure SMTP settings for email delivery within a Webiny project. By adding the `<Api.Mailer.Smtp />` component to your `webiny.config.tsx`, you can programmatically set the host, port, and credentials for email services. It emphasizes using environment variables for secure password handling and running the build command after any configuration changes.
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Overview

Mailer SMTP Configuration

TL;DR

Add <Api.Mailer.Smtp ... /> to your webiny.config.tsx to configure SMTP email delivery at build time. The component serializes the settings into the build artifact — always pass the password via an environment variable, never hard-code it. Deploy the API after making changes.

Core Pattern

import { Api } from "webiny/extensions";

<Api.Mailer.Smtp
    host={"smtp.example.com"}
    port={587}
    user={"smtp-user"}
    password={process.env.SMTP_PASSWORD!}
    from={"noreply@example.com"}
    replyTo={"support@example.com"}   {/* optional */}
/>

Place this inside the JSX returned by your config component in webiny.config.tsx, alongside other <Api.*> extensions.

Props Reference

PropTypeRequiredDescription
hoststringYesSMTP server hostname
portnumberYesSMTP server port (positive integer)
userstringYesSMTP authentication username
passwordstringYesSMTP authentication password — use env var
fromstringYesDefault sender address
replyTostringNoDefault reply-to address

from and replyTo are validated by the email-addresses package against RFC 5322.

Full Example (webiny.config.tsx)

import React from "react";
import { Api, Admin, Core } from "webiny/extensions";

const MyConfig = () => {
  return (
    <>
      {/* ... other extensions ... */}

      {/* Mailer: configure SMTP transport via code */}
      <Api.Mailer.Smtp
        host={"smtp.sendgrid.net"}
        port={587}
        user={"apikey"}
        password={process.env.SENDGRID_API_KEY!}
        from={"noreply@acme.com"}
        replyTo={"support@acme.com"}
      />
    </>
  );
};

Add SENDGRID_API_KEY=your-secret to your .env file (never commit it).

Common Mistakes

MistakeFix
Hard-coding the passwordUse process.env.SMTP_PASSWORD!
process.env.SMTP_PASSWORD undefined at build time → "expected string, received object" errorEnsure the env var is set before deploying
from/replyTo value fails validationMust be a valid RFC 5322 mailbox address
Settings not taking effectRun yarn webiny build api after editing webiny.config.tsx

Quick Reference

# After editing webiny.config.tsx, build the API
yarn webiny build api
Note: This command only works in a dev environment. For other environments, run yarn webiny build api --env=YOUR_ENV instead.
// Environment variable in .env
SMTP_PASSWORD = your - smtp - password - here;

Related Skills

  • webiny-project-structure — Where webiny.config.tsx lives and how extensions are structured
  • webiny-local-development — Running and deploying locally
Info
Category Development
Name webiny-mailer-smtp
Version v20260825
Size 3.88KB
Updated At 2026-09-06
Language