Signup Risk Intelligence API

Stop fake signups and disposable emails in real time

Detect disposable email addresses, suspicious domains, fresh throwaway inboxes, and risky signup patterns with a fast API built for modern SaaS products.

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Real-time detection Risk scoring, not just blocklists Fast API integration
API Response — istmp.email 
{
  "email": "[email protected]",
  "is_disposable": true,
  "risk_score": 87,
  "decision": "block",
  "reasons": [
	"domain_age_lt_30d",
	"mx_matches_disposable_infra",
	"local_part_high_entropy",
	"domain_first_seen_recently"
  ]
}

Decision: allow — risk_score: 12 — Returns a score, decision, and reasons your systems can act on.

The Problem

Blocking known temp domains is no longer enough

Disposable email providers rotate new domains daily. Static blocklists miss them. Your user database pays the price.

  • Fake trial abuse
    Users spin up fresh throwaway accounts to reset free-trial windows.
  • Coupon and promo abuse
    One real person, dozens of fake signups, collecting every welcome discount.
  • Noisy, low-quality user databases
    Fake signups pollute analytics, inflate MAU counts, and waste support bandwidth.
  • Spam signups and lead noise
    Disposable addresses that never engage and never convert distort your funnel.

What static lists miss

fastnewmail.xyz — registered 3 days ago, not on any list yet
xj38qv91@— high-entropy local part, throwaway pattern
MX → shared disposable infrastructure, not a real mail server
istmp.email catches all three signals. Risk score: 87. Decision: block.

How It Works

Multi-signal analysis, not just a blacklist

Every email check runs through multiple layers of analysis to produce an accurate risk score and a clear, actionable decision.

Known Disposable Domain Detection

Cross-references the submitted domain against a continuously updated database of known throwaway email providers.

Domain Age Analysis

Domains registered within days or weeks are a strong signal of throwaway infrastructure. We flag them before blocklists catch up.

MX and Mail Infrastructure Checks

Analyses MX records for patterns associated with bulk disposable services and shared throwaway mail infrastructure.

Suspicious Pattern Detection

Detects high-entropy local parts, random character sequences, and naming conventions associated with throwaway inboxes.

Risk Score and Decision Output

Returns a numeric risk score (0–100) alongside an allow / review / block decision so your systems can act automatically.

Fast API for Signup Workflows

Sub-200 ms responses. Drop into your existing signup or onboarding flow with a single API call. REST JSON. No SDK required.

See all features

Integration

Integrate in minutes

1

Submit the email

POST a single email address to the API at signup time — synchronously, in your existing flow.

2

Analyse all signals

The API checks domain reputation, age, MX infrastructure, local-part patterns, and velocity in real time.

3

Receive score and decision

Get back a risk score, a clear allow/review/block decision, and the specific reasons — ready to act on.

Use Cases

Built for any signup flow

SaaS Free Trial Protection

Stop trial abuse before it starts. Block disposable signups from resetting your free-trial window.

Marketplaces and Communities

Keep your platform clean. Prevent throwaway accounts from bypassing bans or exploiting new-member perks.

E-commerce Account Creation

Prevent coupon abuse, referral fraud, and fake reviews tied to disposable accounts.

Lead Qualification Flows

Score inbound leads at submission time. Disposable emails rarely convert — stop them polluting your CRM.

Waitlists and Beta Access

Ensure waitlist signups are real. Keep your early-access cohort quality high from day one.

Internal Admin and Moderation

Flag risky accounts in your admin dashboard. Use the score as an input to your trust-and-safety workflow.

Why istmp.email

More than a disposable email database

Static blocklists catch yesterday's threats. istmp.email analyses real signals to catch tomorrow's.

Basic temp email lists

  • Exact domain match only
  • Static lists that lag days or weeks behind
  • Binary yes/no result, no context
  • No domain age or MX analysis
  • No visibility into decisions made
  • Miss freshly registered throwaway domains

istmp.email

  • Multi-signal analysis: domain, MX, age, patterns
  • Fresh domain intelligence catches new providers
  • Risk score (0–100) + specific reason codes
  • Domain age and mail infrastructure checks
  • Usage dashboard and API call history (higher plans)
  • Detects entropy patterns, not just known domains

Pricing

Simple, transparent pricing

Start free. Scale when you need to.

Free

$0

/month

100 requests / month

  • Decision + risk score
  • JSON API response
  • Full signals & reason codes
  • Usage dashboard
  • API call history
Start Free

Pro

$19

/month

2,500 requests / month

  • Everything in Free
  • Full signals & reason codes
  • Usage dashboard
  • 14-day call history
Get API Access
Most Popular

Ultra

$59

/month

10,000 requests / month

  • Everything in Pro
  • 90-day call history
  • Team seats (up to 3)
Get API Access

Mega

$149

/month

30,000 requests / month

  • Everything in Ultra
  • 180-day call history
  • Priority support
  • Higher rate limits
Get API Access
View full pricing and plan comparison

FAQ

Frequently asked questions

A disposable email is any address created on a domain designed for short-term or anonymous use — mailinator.com-style services, freshly registered throwaway domains, or domains routing to shared disposable mail infrastructure. istmp.email goes beyond the obvious examples and catches fresh providers not yet on any public list.

No. A static blocklist is just the starting point. istmp.email also analyses domain age, MX record infrastructure, local-part patterns (high-entropy strings, random characters), and first-seen signals. The result is a risk score and a set of specific reasons — not just a boolean match against a list.

Response times are typically well under 200 ms. The API is designed to be called synchronously in a signup or onboarding flow without noticeably affecting perceived load time.

Yes. The Live Demo page lets you check any email address against the API and see the full response — risk score, decision, and reason codes — without creating an account. Production use requires an API key.

The Pro, Ultra, and Mega plans include access to a usage dashboard with API call history. Retention varies by plan: 14 days (Pro), 90 days (Ultra), 180 days (Mega). The Free plan provides API access only.

The response includes both: an is_disposable boolean for quick logic, a risk_score from 0–100, a decision (allow / review / block), and an array of reason codes explaining which signals triggered the result. You can use as much or as little of this as your application needs.

Yes, that is the primary use case. Call the API server-side at the moment of email submission, before completing account creation. Use the decision field to block, flag for review, or allow the signup automatically.

Yes. If the Mega plan does not fit your volume, retention, or SLA requirements, contact us to discuss a custom plan.

Get started today

Protect your signups before the next batch arrives

Detect risky signups before they pollute your user base. No SDK required — one API call is all it takes.

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