Email Checker

A Go tool for validating and analyzing email addresses to detect disposable emails, suspicious patterns, and assess deliverability.

What it does

• Validates email addresses - checks format, DNS records, and deliverability
• Detects disposable emails - identifies temporary/throwaway email providers
• Analyzes email patterns - finds suspicious or bot-generated emails
• Checks domain reputation - verifies against well-known and educational domains
• Risk scoring - provides low/medium/high risk assessment with detailed reasoning

Try it online

Use the UI at: https://emailcheck-api.thexos.dev/

Test the API at: https://emailcheck-api.thexos.dev/check/{email}

Example: https://emailcheck-api.thexos.dev/check/[email protected]

(some rate limits apply)

Features

• Fast concurrent processing for bulk email validation
• SQLite database for caching DNS records and domain lists
• Automatic updates for disposable email and domain lists (every 13 hours)
• Risk analysis with detailed reasoning
• Educational domain detection for universities and schools
• Pattern analysis to detect automated/bot registrations
• Parked domain detection to identify inactive domains
• HTTP API with JSON responses

Installation

1. Install Go 1.24+
2. Clone this repository
3. Run: go mod tidy
4. Build: go build -o checker cmd/email-checker/main.go

Environment Variables

• EMAIL_CHECKER_DB_PATH - Path to SQLite database file (default: checker.db)
• ALLOWED_HOSTS - Comma-separated list of allowed hosts for API (default: localhost:8080)

Usage

Check single email

./checker check [email protected]

Check multiple emails from file

./checker check --file emails.txt

Check emails from stdin

echo "[email protected]" | ./checker check --stdin

Start HTTP server

./checker server --port :8080

OR

Docker

docker build -t email-checker .
docker run -p 8080:8080 email-checker

Then check emails via HTTP:

curl "http://localhost:8080/check/[email protected]"

Update database manually

./checker update

Example Output

{
  "email": "[email protected]",
  "disposable": {
    "checked": true,
    "value": true,
    "error": null,
    "elapsed": 4650774
  },
  "well_known": {
    "checked": true,
    "value": false,
    "error": null,
    "elapsed": 1221592
  },
  "educational": {
    "checked": true,
    "value": false,
    "error": null,
    "elapsed": 3656926
  },
  "dns": {
    "checked": true,
    "value": {
      "domain": "forexzig.com",
      "has_mx": true,
      "has_spf": false,
      "has_dmarc": false,
      "is_parked": false,
      "a_records": [
        "172.67.177.120",
        "104.21.75.139"
      ],
      "ns_records": [
        "adel.ns.cloudflare.com.",
        "nitin.ns.cloudflare.com."
      ],
      "mx_records": [
        {
          "value": "mx2.den.yt.",
          "priority": 10,
          "disposable": true
        }
      ],
      "spf_record": "",
      "dmarc_record": ""
    },
    "error": null,
    "elapsed": 35069721
  },
  "elapsed": 35131609,
  "pattern": {
    "checked": true,
    "value": {
      "short_local_part": false,
      "has_random_pattern": false,
      "too_many_consecutive_numbers": false,
      "too_many_special_chars": false
    },
    "error": null,
    "elapsed": 28608
  },
  "prediction": {
    "risk_level": "high",
    "score": 1,
    "reasons": [
      "Disposable email provider blocked"
    ]
  }
}