Transactional emails are business-critical. Password resets, order confirmations, and security alerts must arrive in seconds, not minutes. The email service you choose determines deliverability, speed, and developer experience.
Overview
Resend: Modern email API built for developers. React Email for building templates. Clean API, TypeScript-first.
SendGrid: Twilio-owned email platform. Handles both transactional and marketing email. Largest feature set, most complex.
Postmark: Focused exclusively on transactional email. Fastest delivery, highest deliverability. Does not offer marketing email.
Delivery Speed
| Provider | Median Delivery Time | 99th Percentile |
|---|---|---|
| Postmark | < 1 second | < 3 seconds |
| Resend | 1-3 seconds | < 5 seconds |
| SendGrid | 5-30 seconds | 1-2 minutes |
Postmark is the fastest by a significant margin. They publish real-time delivery metrics publicly. SendGrid's delivery can be inconsistent, especially on shared IP plans.
Deliverability
| Provider | Inbox Placement Rate | Approach |
|---|---|---|
| Postmark | ~99% | Transactional-only (no marketing email polluting IPs) |
| Resend | ~97% | Dedicated streams for transactional |
| SendGrid | ~90-97% | Mixed traffic (transactional + marketing on shared plans) |
Postmark's advantage: they refuse to send marketing email. Their IP addresses are used exclusively for transactional messages, which means ISPs trust their infrastructure.
Developer Experience
Resend
import { Resend } from 'resend'
import { WelcomeEmail } from '@/emails/welcome'
const resend = new Resend(process.env.RESEND_API_KEY)
await resend.emails.send({
from: 'team@example.com',
to: 'user@example.com',
subject: 'Welcome!',
react: WelcomeEmail({ name: 'John' }),
})
Key feature: React Email integration. Build email templates with React components:
// emails/welcome.tsx
export function WelcomeEmail({ name }: { name: string }) {
return (
<Html>
<Body>
<Heading>Welcome, {name}</Heading>
<Text>Thanks for signing up.</Text>
<Button href="https://example.com/dashboard">
Get Started
</Button>
</Body>
</Html>
)
}
This is a significant DX improvement over HTML string templates.
SendGrid
import sgMail from '@sendgrid/mail'
sgMail.setApiKey(process.env.SENDGRID_API_KEY!)
await sgMail.send({
to: 'user@example.com',
from: 'team@example.com',
subject: 'Welcome!',
templateId: 'd-abc123',
dynamicTemplateData: { name: 'John' },
})
Templates are designed in SendGrid's web editor or uploaded as HTML. Less developer-friendly than React Email.
Postmark
import postmark from 'postmark'
const client = new postmark.ServerClient(process.env.POSTMARK_API_KEY!)
await client.sendEmailWithTemplate({
From: 'team@example.com',
To: 'user@example.com',
TemplateAlias: 'welcome',
TemplateModel: { name: 'John' },
})
Templates use Mustache syntax in Postmark's web editor. Clean and reliable, but not as developer-friendly as React Email.
Pricing
Free Tiers
| Provider | Free Emails/Month | Notes |
|---|---|---|
| Resend | 3,000 | 100/day limit |
| SendGrid | 100/day (3,000/month) | Free forever plan |
| Postmark | 100/month | 30-day trial |
Paid Plans
| Volume | Resend | SendGrid | Postmark |
|---|---|---|---|
| 10,000/month | $20 | $20 (Essentials) | $15 |
| 50,000/month | $50 | $30 | $50 |
| 100,000/month | $80 | $50 | $90 |
| 500,000/month | $250 | $250 | $335 |
| 1,000,000/month | $450 | $500 | $605 |
Pricing is comparable across all three at most volumes. SendGrid is cheapest at higher volumes but comes with deliverability tradeoffs.
Feature Comparison
| Feature | Resend | SendGrid | Postmark |
|---|---|---|---|
| Transactional email | Yes | Yes | Yes |
| Marketing email | Yes (separate) | Yes | No |
| React Email templates | Yes (native) | No | No |
| SMTP relay | Yes | Yes | Yes |
| Webhooks | Yes | Yes | Yes |
| Dedicated IP | Enterprise | $60/month/IP | Included (higher plans) |
| Email analytics | Basic | Advanced | Good |
| Suppression management | Yes | Yes | Yes |
| Bounce handling | Automatic | Automatic | Automatic |
| DKIM/SPF | Yes | Yes | Yes |
| API SDKs | Node, Python, more | 7+ languages | 7+ languages |
| Inbound email | Yes | Yes | Yes |
When to Choose Each
Resend
- React/Next.js teams (React Email is the killer feature)
- Modern developer experience priority
- TypeScript-first projects
- Simple transactional needs (welcome, receipt, reset)
- Building email templates in code (version-controlled)
SendGrid
- Both transactional and marketing email from one platform
- High volume (cheapest at 500K+ emails/month)
- Legacy integration (most established, most SDKs)
- Email marketing features (campaigns, lists, segmentation)
- Enterprise requirements (Twilio backing, compliance certifications)
Postmark
- Deliverability is the top priority (fastest, highest inbox rate)
- Transactional-only needs (no marketing email)
- Mission-critical emails (security alerts, OTPs, financial notifications)
- Healthcare/finance where email must arrive reliably
- Teams that value focused tools over all-in-one platforms
Our Recommendation
We use Resend for most projects because React Email templates are version-controlled, type-safe, and maintain design consistency with our React frontend code. For clients where deliverability is absolutely critical (healthcare, finance), we recommend Postmark.
Contact us to discuss email infrastructure for your application.