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DMARC Record Builder
Generate a DMARC TXT record with explicit policy, alignment and aggregate-report addresses.
Aggregate report mailboxes, one per line
dmarc-record-builder.json (complete report and generated source where applicable)
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
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How to use this tool
- Enter values using the displayed examples; observe the documented input shape and limits.
- Choose Calculate result. Review the complete JSON report and any generated source text it contains.
- Download result to save the complete report; copy the generated source member into your project when relevant. Reset restores examples and clears output.
Examples
Policy: none
DKIM and SPF alignment: r
Aggregate report mailboxes, one per line: reports@example.com
Limitations
- Core DMARC1 tags only; no obsolete pct tag, DNS publication, external-report authorization or enforcement verification. ASCII report addresses.
- Maximum 100,000 UTF-16 units per field, 400,000 UTF-8 combined input bytes, 4 MiB output and 30 seconds in a local worker. Tool-specific bounds may be tighter.
- Generated snippets are source text inside the JSON download. They are never executed by this tool. Local inspection does not verify remote systems or establish standards certification.
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