Email & DNS

SPF Flattening Planner

Plan a conservative SPF include expansion from records you supply.

Calculations run in your browser. The tool does not send your inputs to a server.

01Your inputs

Local workspace

Start with the sample below, or enter your own values.

Root SPF TXT valueThe sample is editable. Keep the input format consistent with the action you choose.

Included records: domain | SPF TXT valueOne current DNS result per line: domain | complete v=spf1 value. Include every nested domain used by the root record.

02Your result

Your result will appear here. Choose an action after checking your inputs.

A quick guide

How to use this tool

Check the example and the unit beside each input.
Enter your values and choose Plan flattening.
Review the result and assumptions, then copy what you need.

Reset example restores the starting values. Clear removes text and number inputs, returns choices to their first valid option, and removes the result.

Reference guide

Explanation and worked examples

Flattening replaces supported include chains with explicit IP mechanisms. It can reduce lookup use, but provider addresses can change, so the generated record requires continuing refresh and review.

Use in day-to-day IT work

Review a proposed replacement for an SPF include chain using supplied current records.

Checks before applying the result

Keep the original record, compare authorised sender ranges and test mail from every legitimate service before replacement.
Flattening removes provider-managed updates. Assign an owner to refresh the snapshot; syntax success does not establish a complete live SPF evaluation.

New to the terminology?

SPF: Sender Policy Framework: authorises sending hosts for a domain used by SMTP.
MTA-STS: A published policy for authenticated TLS delivery to declared MX hosts.
TTL: How long a DNS answer may normally remain cached.

Keep exploring

How calculations work and where the models stop →