Pre-Send Bounce Shield & Verification Studio

The pre-send bounce shield (verifyBeforeSend)

Traditional email APIs blindly accept any address your code sends, dispatch network packets, wait for a 5xx bounce notification hours later, and then penalize your account reputation. SadaSend allows you to verify addresses synchronously before queueing:

TYPESCRIPT

import { SadaSend } from 'sadasend';

const client = new SadaSend({ apiKey: process.env.SADASEND_API_KEY });

// verifyBeforeSend runs real-time deliverability checks before queue insertion
const result = await client.emails.send({
  from: 'notifications@yourdomain.com',
  to: 'user@example.com',
  subject: 'Your Account is Active',
  html: '<p>Welcome aboard!</p>',
  verifyBeforeSend: true,
});

The Zero-Debit Send Guarantee

With SadaSend’s Pre-Send Bounce Shield, you never pay to find out that an address was undeliverable:

• If an address fails verification (e.g. invalid syntax, non-existent MX host, or disposable burner mailbox), SadaSend rejects the request with HTTP 422 undeliverable_recipient.

• Zero Quota Deducted: Exactly zero emails are deducted from your monthly dispatch allowance or prepaid credits.

• Reputation Intact: Because no network packet was dispatched to the destination mail server, your domain records zero bounce events with mailbox providers.

Four-tier deliverability heuristics

SadaSend executes four sequential verification layers in under 50ms:

1. RFC 5322 Syntax Validation: Verifies address structure, character encodings, and domain syntax.

2. Live DNS MX & Null MX Lookups: Confirms active mail exchangers and flags RFC 7505 Null MX dead domains.

3. Disposable & Burner Shield: Detects 188+ temporary email services (Mailinator, TempMail, GuerrillaMail) to prevent fake signups and trial abuse.

4. Domain Typo Auto-Correction: Identifies misspelled consumer domains (@gmaill.com, @hotmial.com, @yaho.com) and suggests corrections.

Standalone verification API & MCP tool

You can also verify email addresses independently of sending—ideal for user signup forms, onboarding flows, or AI agent lead validation:

BASH

curl -X POST https://api.sadasend.com/verify \
  -H "Authorization: Bearer sada_live_sk_..." \
  -H "Content-Type: application/json" \
  -d '{ "email": "alex.dev@gmaill.com" }'

Verification response schema & diagnostics

Every verification call returns rich deliverability telemetry including syntax checks, domain typo corrections, disposable mailbox tags, and active MX status:

JSON

{
  "email": "alex.dev@gmaill.com",
  "status": "undeliverable",
  "score": 0.15,
  "reasons": ["domain_typo_detected"],
  "suggestion": "alex.dev@gmail.com",
  "is_disposable": false,
  "is_role_account": false,
  "mx_found": true
}

Batch CSV list cleaning

Clean entire customer databases or legacy contact lists before launching transactional campaigns. Upload CSV files via the web dashboard (/app/verify) or the batch API (up to 10,000 addresses per batch on Scale). Download complete deliverability scorecards with single-click suppression exports.