SPF Flattener

Collapse nested SPF includes into a single record that uses only IP addresses — zero DNS lookups, no 10-lookup limit.

If you enter a domain, we'll fetch its live SPF record first.

Why flatten SPF?

SPF is limited to 10 DNS lookups when it is evaluated. Each include: (for Google, a CRM, an ESP, etc.) can consume several. Cross the limit and SPF returns permerror and fails — even though your record looks correct.

What flattening does

Flattening resolves the include: mechanisms down to their underlying IP addresses, so your record uses ip4:/ip6: entries instead of chained lookups. That keeps you safely under the limit.

The trade-off

Flattened records must be kept in sync: if a provider changes its sending IPs, your hardcoded list goes stale. Re-check periodically, or only flatten the includes that are stable.

Frequently asked questions

What is the SPF 10 lookup limit?
When SPF is evaluated it may perform at most 10 DNS lookups. Exceeding this causes a permerror, which means SPF fails for your domain.
Is flattening safe?
It is safe as long as you keep the resulting IP list up to date. If a sender changes IPs, a flattened record can go stale and start failing legitimate mail.
How do I know I am over the limit?
Validate your SPF record — if it reports a permerror or "too many DNS lookups", you are over 10 and should flatten or remove unused includes.
Is the flattener free?
Yes, flattening your SPF record here is free.