Email verification API

Validate every email before it costs you revenue.

Screen out typos, disposable inboxes, and risky addresses in real time. EmailAPI gives product, growth, and operations teams a single verification endpoint they can trust at signup, import, and checkout.

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Layered checks

Syntax, MX and SMTP

Move beyond regex and validate deliverability signals before an address enters your system.

Risk signals

Disposable and catch-all awareness

Route risky addresses differently and protect campaign quality without blocking every edge case.

Developer first

Simple JSON responses

Integrate one endpoint into your form, CRM, or billing flow and act on clear validation outcomes.

Live example

What your app sees in one response

POST /v1/validate

{
  "email": "maya@northstar.io",
  "result": "deliverable",
  "valid": true,
  "score": 0.98,
  "checks": {
    "syntax": true,
    "mx": true,
    "smtp": true,
    "disposable": false,
    "role": false
  }
}

Verdict

Safe to onboard

Deliverability

Mailbox and domain checks passed

Routing

Create account immediately

{
  "email": "ops@sample-catchall.com",
  "result": "risky",
  "valid": true,
  "score": 0.63,
  "checks": {
    "syntax": true,
    "mx": true,
    "smtp": null,
    "catch_all": true,
    "disposable": false
  }
}

Verdict

Accept with caution

Use case

Flag for nurture or double opt-in

Routing

Lower trust until engagement proves quality

{
  "email": "trialbox@instantmail.dev",
  "result": "undeliverable",
  "valid": false,
  "score": 0.09,
  "checks": {
    "syntax": true,
    "mx": true,
    "smtp": false,
    "disposable": true,
    "role": false
  }
}

Verdict

Block or request another address

Risk

Temporary mailbox pattern detected

Routing

Protect onboarding and sender reputation

Built for high-signal entry points

One verification standard across every email touchpoint.

Use the same validation policy anywhere poor email quality creates cost: signups, lead capture, checkouts, CRM imports, and outbound segmentation.

Signup forms

CRM cleanup

Checkout flows

Lead routing

Why EmailAPI

Clean decisions, not vague validation noise.

Return structured signals your product can act on immediately, so technical teams can integrate quickly and commercial teams can trust the buying story.

Real-time verification

Validate emails before account creation, quote requests, or checkout submissions so low-quality data never becomes downstream work.

Syntax and domain checks in the same call.
Mailbox-level signals to separate deliverable from risky addresses.

Actionable risk signals

Catch-all, disposable, and role-based outcomes help you decide when to accept, challenge, nurture, or block an address.

Differentiate high-confidence signups from low-trust leads.
Protect sender reputation before bad contacts reach campaigns.

Developer-ready responses

Predictable JSON and clean field semantics make it easy to plug the API into forms, imports, and internal tooling without custom parsing.

Shape onboarding rules around clear result states.
Keep implementation lightweight with a single verification endpoint.

Integration flow

Add verification without slowing product delivery.

Keep the integration surface simple: validate once, inspect the result, and route each email according to confidence and risk.

Step 1

Send the email to one endpoint

Call validation at signup, import, or billing capture with minimal payload and predictable latency.

Step 2

Read the result and supporting checks

Use the score and check outcomes to distinguish clean, risky, and blocked addresses.

Step 3

Route users with confidence

Approve immediately, require confirmation, or ask for another address depending on the signal strength.

Example integration

Use the response as a routing layer

JSON over HTTPS

curl -X POST https://api.example.com/v1/validate \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "email": "maya@northstar.io"
  }'

Ready for both self-serve buyers and larger volume conversations.

Choose a commercial path that fits your stage, from straightforward API access for product teams to higher-throughput partnerships for larger send volumes.

For growing teams

Usage-based API access

A clean entry point for products that need verification in forms, signups, and operational workflows.

For larger operations

Higher throughput and partnership support

Add dedicated onboarding, SLA coverage, or custom commercial terms as your verification workload grows.

Built for trust

Technical credibility without enterprise fluff.

Clear examples, direct language, and structured outcomes help buyers understand the product quickly without digging through documentation first.

Clear outcomes

Show the endpoint, the response shape, and the recommended action within the first scroll.

Scales with volume

Support both product-led adoption and larger procurement conversations from the same foundation.

Next step

Protect every list before it becomes a deliverability problem.

Use real-time validation as the first layer of email quality, then expand into stronger onboarding, segmentation, and lifecycle messaging decisions.

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