Verify emails in Node.js with Verifly

Email verification on modern Node.js

Since Node 18, the global fetch API is built in, which means you no longer need axios or node-fetch just to call an HTTP service. That makes Verifly especially convenient in Node: verifying an address is one await away, with no dependency to install and no SDK to keep in sync. Whether you are running an Express server, a Fastify API, a Next.js route handler, or a serverless function on Vercel or AWS Lambda, the same handful of lines works everywhere.

The problem Verifly solves is one every Node backend hits eventually. A signup form, a waitlist, or an imported CSV feeds you addresses, and validator libraries such as validator.js only check that the string looks like an email. They cannot tell you that the mailbox was deleted, that the domain is a disposable throwaway, or that the address is a generic role@ inbox nobody reads. Verifly performs a live SMTP probe and returns a JSON body with a result of deliverable, undeliverable, or risky plus disposable, role, catch-all, and smtp flags — exactly the shape you want to destructure and branch on.

Because pricing is pay-as-you-go from $2 per 1,000 checks down to $0.60 per 1,000 at volume, it scales from a hobby project to production without a plan change. Self-register for 100 free credits — no card, no captcha — and the same vf_ key works from local dev, a container, or an edge function.

Batch-verify an array of emails in Node.js

For anything beyond a single address, post the whole set to /verify/batch instead of firing dozens of requests. Send a JSON body with an emails array and get back a results array you can filter with the array methods you already use. This keeps latency low and cost predictable, which matters inside a serverless function with an execution-time budget.

const emails = [
  'ada@example.com',
  'info@some-domain.com',
  'noreply@disposable.tld',
]

const res = await fetch('https://verifly.email/api/v1/verify/batch', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer vf_YOUR_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({ emails }),
})

const { results } = await res.json()
const clean = results.filter((r) => r.result === 'deliverable')
console.log(`Keeping ${clean.length} of ${results.length}`)
for (const r of results) {
  if (r.disposable || r.role) console.log('drop:', r.email, r.result)
}

Guard an Express or Next.js signup route

The best place to verify in a Node app is the endpoint that creates an account. A short-timeout fetch, wrapped so a network error fails open rather than blocking the user, lets you reject disposable addresses and warn on undeliverable ones before you write the row. Use an AbortController to cap the wait so verification never becomes a bottleneck on your signup path.

async function isEmailOk(email) {
  const ctrl = new AbortController()
  const t = setTimeout(() => ctrl.abort(), 8000)
  try {
    const url = new URL('https://verifly.email/api/v1/verify')
    url.searchParams.set('email', email)
    const res = await fetch(url, {
      headers: { Authorization: 'Bearer vf_YOUR_KEY' },
      signal: ctrl.signal,
    })
    const data = await res.json()
    if (data.disposable) return false
    return data.result !== 'undeliverable'
  } catch {
    return true // fail open on network error
  } finally {
    clearTimeout(t)
  }
}