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Envelope by Avasis.ai
Envelope by avasis.ai
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Part of Avasis.ai · OS for AI Agents

One API for everyResendResendPostmarkPostmarkMailgunMailgunemail providerSendGridSendGridSESSESAgentMailAgentMail

Your transactional emails hit Postmark. Your bulk sends hit SES. When a provider goes down, the next one picks up — automatically. Every send gets a content quality score before it leaves.

Start free →Read the docs
5 providers connectedFailover in <50msAnti-slop gate built in
request
POST /api/v1/send { "from": "hello@acme.com", "to": "user@documenso.com", "subject": "Your document is ready", "type": "transactional" }
response200 OK
{ "provider": "postmark", "status": "sent", "messageId": "msg_01hx9abc", "slopScore": 100, "slopFindings": 0 }
✓ Routed to Postmark — type: transactional✓ slopScore 100 — content clean✓ Failover ready: Resend → SES
Works with
Resend logoResend
Postmark logoPostmark
Mailgun logoMailgun
SendGrid logoSendGrid
Amazon SES logoAmazon SES
How it works

Set up in 5 minutes

1

Connect

Add your provider API keys. Resend, Postmark, SES — or all five.

Active providers

Resend
Postmark
Amazon SES
2

Send

POST /api/v1/send with { type: "transactional" }. Envelope picks the provider.

POST /api/v1/send
{
type: "transactional",
to: "alice@acme.com"
}
// → routed to Postmark (58ms)
3

Monitor

See delivery rates, open rates, and content scores per provider in one dashboard.

Delivery rate

Resend
88%
Postmark
95%
SES
72%
Features

Smart routing decides in milliseconds

Smart Routing

OTPs to Postmark. Bulk to SES. Automatically.

Set one rule. Envelope routes every email to the cheapest, fastest, or most reliable provider — and switches instantly if one goes down. No code changes.

await envelope.send({ type: 'otp' })
OTPPostmark
Fastest58ms
BulkSES
Cheapest120ms
NotifyResend
Best DX89ms
↻ Failover: Postmark → Resend → SES
Unified Analytics

Delivery stats across every provider. One view.

Stop switching tabs between Resend, SES, and Mailgun. See deliverability, opens, and bounces across all your providers in a single view.

Envelope unified analytics dashboard showing delivery rates across Postmark, Resend, and SES
Content Quality Gate

Your AI sends email. We make sure it doesn't sound like AI.

Every send gets scored against 40+ patterns before it leaves your system. Blocked phrases, passive voice, AI tells — caught before delivery.

Before
"Unlock seamless transformation for your revolutionary workflow"
55/100
Blocked
Blocked:
unlockrevolutionary
Warnings:
seamless
Auto-fixed
After
"We fixed a critical issue in your document. Reply to this email or click below to review the changes."
95/100
Sent via Postmark
0 blocked patterns
0 warnings

Scores every send

No manual review needed

Sub-millisecond

Zero latency overhead

Configurable threshold

Block at score < 60, or customize

Email Designer

Design beautiful emails,
no code required

Drag-and-drop editor with live preview, variable support, and one-click deploy.

Email Designer
DesktopMobile

Components

▬Header
≡Text
⬜Button
⬛Image
─Divider

Acme Inc.

Welcome, {{name}}!

We're excited to have you on board.

Get started →

Properties

Background

#3D8DFF

Text Color

#ffffff

Font size

18px

Padding

24px

Start from a template

Welcome

Onboarding

Magic Link

Auth

OTP Code

Auth

Invoice

Billing

Order

Commerce

Reset

Auth

Email Templates

Beautiful templates, ready to send

8 production-ready designs. Edit variables, preview live, deploy to any provider.

envelope
Welcome Email
Welcome EmailOnboarding
envelope
Order Confirm
Order ConfirmCommerce
envelope
Invoice Receipt
Invoice ReceiptBilling
envelope
Notification
NotificationStatus
envelope
Magic Link
Magic LinkAuth
envelope
OTP Code
OTP CodeAuth
envelope
Newsletter
NewsletterMarketing
envelope
Password Reset
Password ResetAuth
Open Email Designer →
Developer-first

One SDK. Every provider.

// In any AI agent (Claude, Kiro, Cursor...)
const result = await mcp.call('send_email', {
  from:     'hello@acme.com',
  to:       'alice@example.com',
  template: 'welcome',
  vars:     { name: 'Alice' },
})
// Envelope handles routing, failover,
// and analytics transparently.
Pricing

Start free. Pay when you scale.

Start free. Scale as you grow. No hidden fees.

Free

$0forever
  • 1 email provider
  • 1,000 emails/mo
  • Anti-slop scoring
  • API access
  • Community support
Start free

Starter

$29/month
  • 3 providers
  • 50,000 emails/mo
  • Automatic failover
  • Anti-slop scoring
  • 30-day analytics
  • Priority support
Get started
Recommended

Pro

$99/month
  • Unlimited providers
  • Unlimited emails
  • Automatic failover
  • MCP server
  • White-label
  • 90-day analytics
  • Priority support
Go Pro

All plans include API access, CLI, anti-slop scoring, and email designer. No setup fees.

Start routing in 5 minutes

Connect your first provider free. Add more as you grow.

Start free →Read the docs →