Email API
Email API: what it is and how to send from your app
An email API is HTTPS email for developers. One authenticated request sends the message; the provider handles delivery. Notify is a minimal transactional email API — you own the HTML, we deliver.
How an email API works
Your app authenticates with an API key, posts JSON (to, from, subject, message), and the provider queues, signs, and delivers the mail. Delivery events can come back as webhooks; dashboards show logs. That is the whole loop — no SMTP ports on your server.
- Create an API key
- Verify your sending domain (SPF / DKIM)
POST /api/email/send- Watch logs; subscribe to webhooks on Pro+
Email API vs SMTP vs ESP
Email API
HTTPS + API key. Fits serverless and modern backends. Notify’s model.
SMTP
Protocol-level send. Fine for legacy; painful on Workers and many PaaS defaults. SMTP vs APIs
ESP
Full email service platform — often marketing + transactional. Useful when you need campaigns; overkill for app mail alone.
Send with Notify
Canonical endpoint: POST https://notify.cx/api/email/send with header x-api-key. Body: to, from, subject, message.
// Using Fetch API
const response = await fetch('https://notify.cx/api/email/send', {
method: 'POST',
headers: {
'Content-Type': 'application/json',
'x-api-key': 'your-api-key'
},
body: JSON.stringify({
to: 'user@example.com',
from: 'noreply@your-verified-domain.com',
subject: 'Welcome aboard!',
message: '<h1>Welcome!</h1><p>Thanks for joining us.</p>'
})
});
const data = await response.json();Pricing: Free 1,000/mo · Pro $10 / 10,000 · Scale $50 / 100,000. Email API pricing comparison · Quick start
Keep exploring
Best for
Developers building apps, websites, agents, and startups who need password resets, onboarding, receipts, and notifications.
Not for
Newsletter platforms, marketing automation, or drag-and-drop template studios.
Frequently asked questions
What is an email API?
An email API lets your application send email over HTTPS — typically with an API key — instead of speaking SMTP yourself. You POST to, subject, and body; the provider handles delivery, authentication, and often logs and webhooks.
Email API vs SMTP — which should I use?
For new apps and serverless environments, prefer an email API. SMTP still works for legacy software that can only speak SMTP. See SMTP vs email APIs on the Notify blog.
What is a transactional email API?
A transactional email API is built for triggered messages — password resets, receipts, alerts — not newsletters. Notify is a transactional email API: send, webhooks, logs.
Do I need an SDK to use an email API?
No. Notify’s recommended path is one fetch with an x-api-key header. Some providers lead with official SDKs; that is optional for Notify.
How much does an email API cost?
Notify: Free 1,000 emails/mo, Pro $10 for 10,000, Scale $50 for 100,000. Other providers use plans or per-email pricing — compare on /pricing and /email-api/pricing.
What about SPF, DKIM, and DMARC?
You verify a sending domain so providers can authenticate mail. Notify walks you through DNS; production custom from addresses require a verified domain.
Best email API for developers?
Depends on the job. Choose Notify if you want minimal send + observe and flat pricing. Choose Resend if you plan on managing templates in React Email and want their SDK stack. Choose Postmark for deliverability brand, SES for raw AWS cost at scale.