Brew Welcome Email Platform

A Next.js app that sends a transactional welcome email via the Brew SDK every time a user signs up.

How It Works

1. User fills out the signup form (email, first name, last name)
2. Their contact is upserted into Brew with source: "signup"
3. A pre-made welcome email is sent to their inbox instantly via Brew

Setup

1. Install dependencies

npm install

2. Get your Brew credentials

• API key: Go to brew.new/settings/api and create an API key.
• Welcome email: Go to brew.new and create a welcome email. Once it exists, click into that specific email template — the URL will look like https://brew.new/emails/<emailId>. Copy the <emailId> segment from the URL; that is the value you'll use for BREW_WELCOME_EMAIL_ID. If you ever swap the welcome email for a different template, repeat this step and update the value in both .env.local and Vercel → Settings → Environment Variables, then redeploy.
• Sending domain: Go to brew.new settings and verify a sending domain — copy its domainId.

3. Create .env.local in the project root

BREW_API_KEY=brew_your_key_here
BREW_WELCOME_EMAIL_ID=your_email_id_here
BREW_DOMAIN_ID=your_domain_id_here

4. Set up the Signups audience in Brew

• Go to brew.new → Audience → New Audience
• Set filter: source equals signup
• Save as "Signups"
• All signup form submissions will appear here automatically

5. Run locally

npm run dev

6. Deploy to Vercel

• Push to GitHub and import in Vercel
• Add the three env vars in Vercel → Settings → Environment Variables (the same values from .env.local, including the BREW_WELCOME_EMAIL_ID you copied from the email template URL)
• Redeploy so the new env vars are picked up (env var changes do not apply to existing deployments)
• If you later change the welcome email template, update BREW_WELCOME_EMAIL_ID in both .env.local and the Vercel dashboard, then redeploy

Pages

• / — Signup form
• /admin — Shows your domains, emails, contact count, and audiences
• /admin/contacts — Full contact list with verification status

Optional: Generate a unique email per signup instead of a static one

If you want Brew to AI-generate a fresh welcome email for every signup instead of using a pre-made one, replace the sends flow in src/app/api/signup/route.ts with:

const generated = await brew.emails.generate({
  prompt: `Create a warm friendly welcome email for ${firstName} ${lastName} who just signed up. Use the brand's design and tone. Include a welcome message and a get started CTA.`,
})

if (!('emailId' in generated)) {
  return NextResponse.json(
    { error: 'Email generation failed' },
    { status: 500 }
  )
}

await brew.sends.create({
  emailId: generated.emailId,
  domainId: process.env.BREW_DOMAIN_ID!,
  subject: `Welcome, ${firstName}!`,
  emails: [email],
})

Note: This approach costs Brew credits per signup and adds 30–90 seconds to the signup response (per the SDK's documented agent runtime). Recommended for low-volume or personalized flows only. Remove BREW_WELCOME_EMAIL_ID from your env vars if using this approach, and set export const maxDuration = 300 in the route so Vercel's serverless timeout doesn't kill the request mid-generation.