Check a domain's SPF, DKIM, DMARC and blacklists, read headers and DMARC reports, open .eml files and clean up your copy. Free, no sign-up, and almost all of it runs in your browser.
SPF, DKIM, DMARC, MX, MTA-STS, TLS-RPT, BIMI and blacklists in one run, scored out of 100 with a fix list.
Validate the SPF record, follow every include, and count DNS lookups against the limit of 10.
Find the DKIM public key for a selector (or auto-detect common ones) and check its size and flags.
Read the DMARC policy, alignment and reporting tags, and check that report addresses will accept reports.
Check the BIMI record, the SVG Tiny PS logo, the mark certificate and the DMARC policy BIMI depends on.
Fetch the MTA-STS policy, check its mode and max_age, and confirm it covers every MX host.
Validate the _smtp._tls record against RFC 8460 and see where TLS failure reports are sent.
Check a sending IP against 18 email DNS blacklists, grouped by how much each one matters.
Check whether a domain, or the domain of an email address, is on a domain or URI blacklist.
Trace a message hop by hop, read the receiver's SPF/DKIM/DMARC verdicts and check DMARC alignment.
Open .eml and .emlx files in the browser: rendered body, headers, authentication and attachments.
Drop in DMARC aggregate reports (XML, .gz, .zip) to see pass rates, failing sources and what to fix.
The domain, record, blacklist, header and copy checks are JSON endpoints under https://powerline.ai/api/tools/ and tools on a hosted MCP server at https://powerline.ai/mcp. No key, no account.
{
"mcpServers": {
"powerline-email-tools": { "type": "http", "url": "https://powerline.ai/mcp" },
"powerline-inbox-preview": { "type": "http", "url": "https://api.powerline.ai/v1/mcp" }
}
}