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Overview

Alias detection identifies plus-addressing (also called subaddressing), where users add a tag to their email address like [email protected]. This allows one email address to create unlimited variations.
Typically configured as FLAG since aliases can indicate multi-accounting but are also used legitimately.

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What is Plus-Addressing?

Plus-addressing allows users to add a tag after a + symbol: 
[email protected]           # Base email
[email protected]  # Shopping alias
[email protected] # Newsletter alias
All these deliver to the same inbox: [email protected]

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Why It Matters

  • Multi-accounting: Users can bypass “one account per email” limits
  • Trial abuse: Create unlimited free trial accounts
  • Referral fraud: Exploit referral programs

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API Response

{
  "checks": {
    "alias": {
      "pass": false,
      "latency": 0.3
    }
  },
  "signals": ["alias_pattern"]
}
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pass
boolean
false if plus-addressing detected, true if not
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latency
number
Check execution time in milliseconds

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Configuration

FLAG

Recommended to FLAG aliases since they can be legitimate but may indicate abuse.

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Next Steps

Device Fingerprint

Track multi-account abuse

Disposable

Block temporary emails