Reverse MX Lookup API - Find Domains by Mail Server

Try it now - no signup required:

curl "https://domscan.net/v1/reverse/mx?mx=aspmx.l.google.com"

Example Response

{
  "mx_server": "aspmx.l.google.com",
  "provider": "Google Workspace",
  "domain_count": 8500000,
  "sample_domains": [
    "uber.com",
    "spotify.com",
    "airbnb.com",
    "dropbox.com",
    "slack.com"
  ],
  "priority_distribution": {
    "10": 4200000,
    "20": 2100000,
    "30": 2200000
  }
}

Key Features

Domain Discovery

Find all domains using a specific mail exchanger.

Provider Identification

Detect email service providers (Google, Microsoft, etc.).

Company Discovery

Find related domains belonging to the same organization.

Priority Analysis

See MX priority distribution across domains.

Email Infrastructure Mapping

Understand email routing relationships.

Competitive Intelligence

See which companies use specific email providers.

Migration Planning

Identify domains for email migration projects.

Security Research

Analyze email infrastructure for security assessments.

Frequently Asked Questions

What is an MX record?

MX (Mail Exchanger) records specify which mail servers receive email for a domain. They include a priority value and server hostname.

How do you find domains by MX?

We aggregate DNS data from zone files, passive DNS, and domain registrations to map MX server to domain relationships.

Why use reverse MX lookup?

Common uses include: finding company domains, competitive analysis, security research, identifying email provider customers, and M&A due diligence.

How current is the data?

Our MX mapping is updated daily through continuous DNS monitoring and zone file analysis.

Reverse MX Lookup

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View Full API Documentation