Email Validation Strategy
Vouch performs multiple validation checks on every email address to ensure comprehensive fraud detection and email quality assurance. Each validation type can be individually configured to either allow, flag, or block based on your requirements.Validation Types
Syntax
RFC 5322 email format validation
Disposable
Temporary email detection
MX Records
Domain mail server verification
Role Email
Generic role address detection
Alias
Plus-addressing detection
Device Fingerprint
Multi-account device tracking
IP Reputation
VPN, Tor, and fraud detection
Coming Soon: SMTP verification and Catch-all detection are currently in development.
Validation Categories
Email Format Validation
These checks verify the email address itself is valid and deliverable:Syntax Validation
Syntax Validation
Ensures the email conforms to RFC 5322 standards. This is the most basic check that catches obvious typos and malformed addresses.Common failures:
- Missing @ symbol
- Invalid characters
- Malformed domain
- Missing local or domain part
MX Records
MX Records
Verifies that the email domain has valid mail exchange (MX) records configured in DNS. Without MX records, the domain cannot receive emails.What it checks:
- DNS MX record existence
- At least one valid mail server
- Proper DNS configuration
Quality & Risk Detection
These checks identify potentially problematic or risky email addresses:Disposable Email Detection
Disposable Email Detection
Identifies temporary email services like Mailinator, Guerrilla Mail, or 10minutemail. These are often used for spam, fraud, or to avoid long-term commitment.
Role Email Detection
Role Email Detection
Detects generic organizational emails like admin@, support@, or info@ rather than personal email addresses.
Alias Detection
Alias Detection
Identifies plus-addressing ([email protected]) which allows one email address to create unlimited variations.
Fraud & Device Detection
These checks identify patterns associated with fraudulent behavior:Device Fingerprinting
Device Fingerprinting
Creates a unique fingerprint of the user’s device to track it across multiple signups. Detects when the same device is used to create many accounts.
IP Reputation
IP Reputation
Analyzes the user’s IP address to detect VPNs, Tor networks, proxies, data centers, and known fraudulent IPs.
How Validation Works
All validation checks run in parallel for maximum speed. Vouch uses an intelligent early-exit strategy where BLOCK-configured checks can terminate validation early, while FLAG and ALLOW checks run to completion to gather maximum intelligence.Configuration per Check
Each validation type can be configured independently:| Action | Behavior | When to Use |
|---|---|---|
| ALLOW | Check runs but doesn’t affect recommendation | Gathering data only |
| FLAG | Failure marks email as suspicious | Review recommended |
| BLOCK | Failure immediately blocks email | Critical checks |
Validation Response Structure
Each validation returns a consistent structure with the following fields:Field Definitions
Whether the check passed (true) or failed (false)
The configured action for this check:
allow, flag, or blockHuman-readable description of the result
Recommendation Logic
The final recommendation is determined by aggregating all validation signals. If any BLOCK-configured check fails, the recommendation is “block”. If any FLAG-configured check fails, the recommendation is “flag”. Otherwise, the recommendation is “allow”.Recommendation Values
allow
Email passed all checks. Safe to proceed with account creation.
flag
Suspicious signals detected. Consider manual review or additional verification.
block
Critical validation failed. Reject this email address.
Default Configuration
By default, Vouch uses this configuration:| Validation | Default Action | Rationale |
|---|---|---|
| Syntax | BLOCK | Invalid format cannot receive email |
| Disposable | BLOCK | Temporary emails indicate fraud |
| MX Records | BLOCK | No mail server means undeliverable |
| Role Email | ALLOW | Often legitimate but worth tracking |
| Alias | FLAG | Can indicate multi-accounting |
| Device Fingerprint | FLAG | Multiple accounts may be legitimate |
| IP Reputation | FLAG | VPNs used legitimately by some users |
Performance Characteristics
- Average validation time: 150-300ms
- Early exit scenarios: 50-150ms
- Full validation: 300-500ms
Best Practices
Start Conservative
Start Conservative
Begin with more checks set to FLAG rather than BLOCK. Review flagged accounts to understand your user base before tightening restrictions.
Combine with Other Signals
Combine with Other Signals
Use Vouch validation alongside your own business logic and risk scoring for the most comprehensive fraud prevention.