BIMI Checker

New BIMI Validation tool

by Matthew Vernhout / BIMI Group · github.com/authindicators/bimi-checker · website

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Install

No release zip yet. The repository archive installs, but the folder name will carry the branch suffix and updates will not flow:

wp plugin install https://github.com/authindicators/bimi-checker/archive/refs/heads/main.zip

Readme github.com/authindicators/bimi-checker ↗

A WordPress plugin for checking BIMI and DMARC records for a domain. Use the [bimi_checker] shortcode to embed the checker on a WordPress site.

Features

BIMI

Look up BIMI records using selector._bimi.domain
Optional selector input, defaulting to default
Ignore unrelated TXT responses that are not BIMI records
Support BIMI Organizational Domain fallback where the Organizational Domain can be determined safely
Display the full BIMI TXT record used for validation
Parse and display l=, a=, avp=, and lps= tags
Validate HTTPS requirements for l= and populated a= values
Identify expected SVG/SVGZ logo URI formats and flag suspicious logo resources such as .pem
Recognize .pem as the expected/common evidence-document URI format and warn about other formats
Validate avp=brand and avp=personal values
Detect and validate the BIMI lps= Local-part as Selector tag
Recognize an empty lps= value as valid and meaningful
Parse comma-separated LPS prefixes and report malformed values
Explain when a sender local-part is required to complete an LPS selector lookup

DMARC

Look up _dmarc.domain
Ignore unrelated TXT responses that are not DMARC records
Check p= for quarantine or reject
Check explicitly published sp= policy
Treat an omitted pct= as the effective default of 100
Warn when an explicitly published pct= is not 100
Report whether rua= is present

DNS and diagnostics

WordPress settings page for DNS resolver configuration
Use the system/local DNS resolver or configured external DNS resolvers
Configurable DNS timeout and retry settings
AJAX diagnostics with clearer error reporting

Display

Pass, warning, and error status indicators
Clickable a= and l= URLs
Responsive results layout
Inbox-style BIMI logo preview

Current release

Version 1.1.0

The results display uses the existing green, amber, and red status indicators. The lps= row is always shown: absent values appear as an amber —, while published values are displayed directly. The validator also evaluates malformed LPS values, although the current compact LPS display only distinguishes published from absent values.

Installation

Upload the plugin files to /wp-content/plugins/bimi-checker, or install the plugin through the WordPress plugins screen.
Activate BIMI Checker.
Configure DNS resolver options under Settings → BIMI Checker, if required.
Add the [bimi_checker] shortcode to a post, page, or widget area.

Usage

Basic shortcode:

[bimi_checker]

Visitors can enter a domain and optionally specify a BIMI selector. If no selector is supplied, the checker uses default.

BIMI validation notes

The checker performs DNS and URI-format checks. It does not fetch and validate the SVG/SVGZ file contents or the evidence document itself.

A BIMI l= value must use an HTTPS URI. A .svg or .svgz filename is expected/common, but the BIMI specification does not require the URI itself to end with one of those extensions. Suspicious formats, such as an l= URI pointing to a .pem file, are flagged.

An a= value may be empty. When populated, it must use HTTPS. .pem is the expected/common filename format for BIMI evidence documents; other formats are reported as warnings rather than automatically treated as invalid.

For lps=, the validator checks the published Local-part as Selector configuration. The current compact display shows whether the tag is published and its value, but does not visually distinguish malformed published values from valid ones. A complete LPS lookup depends on the normalized RFC5322.From local-part, so the DNS record alone is not always sufficient to test the resulting secondary selector.

Frequently Asked Questions

What is BIMI?

BIMI stands for Brand Indicators for Message Identification. It allows participating mailbox providers to associate an authenticated email domain with a published brand indicator.

What do I need for BIMI to work?

BIMI requires an appropriately configured BIMI record and qualifying DMARC enforcement. Additional requirements, including evidence documents or other eligibility criteria, can vary by mailbox provider.

Does the checker modify DNS?

No. BIMI Checker only looks up, validates, and reports records. DNS changes must be made through the applicable DNS hosting provider.

Does the plugin validate every possible BIMI implementation requirement?

No. The checker evaluates the BIMI and DMARC information it can determine from DNS and the implemented validation tests. Mailbox providers can apply additional requirements and policies before displaying an indicator.