Sender Policy Framework, automated

Stop hitting the SPF
10‑lookup limit.

Solid SPF resolves and flattens your SPF includes into a compact, standards‑compliant record — and keeps it updated automatically as providers like Google Workspace and Microsoft 365 change theirs.

Start free Read the docs

You publish once

customer.com.  TXT  "v=spf1 include:customer-com-a1b2c3.flat.solidspf.com ~all"

Point your domain at a managed record under our hosting domain.

We keep it flattened & fresh

customer-com-a1b2c3.flat.solidspf.com.  TXT  "v=spf1 ip4:192.0.2.1 ip4:198.51.100.0/24 ip6:2001:db8::/48 -all"

We refresh every 15 minutes, track upstream changes, and never publish a broken record.

Why Solid SPF

Under the limit, always

Flattening collapses include/a/mx lookups into ip4/ip6 so receivers never permerror on your mail.

Tracks upstream changes

When Google, Microsoft, Mailchimp, SendGrid or Salesforce change their SPF, we detect it and regenerate — automatically.

Safe by design

We keep the last known‑good record if a refresh fails, version every change, and let you roll back instantly.

Change visibility

See exactly what changed between versions and get alerted when dependencies move materially.

Passwordless

Sign in with passkeys or email magic links. No passwords to leak, reuse, or reset.

Built on Cloudflare

Serverless Workers, D1, KV and Cloudflare DNS. Fast, global, and inexpensive to run.

The SPF 10‑lookup problem

SPF (Sender Policy Framework) limits a record to 10 DNS‑lookup mechanisms (include, a, mx, ptr, exists, and redirect). Stack a few email providers and you blow past it — receivers then return permerror and may reject or unauthenticate your mail. Flattening replaces those lookups with the resolved IP ranges, dropping your lookup count toward zero while preserving your intended -all/~all policy.

Learn about lookup limits

Simple, flat pricing

$10 / domain / month

Every managed domain includes automatic 15‑minute refreshes, version history, rollback, and email alerts.

Get started