Simplify · Optimize · Stay Within Limits
SPF Flattener / Simulator
Expand all include statements, simulate SPF flattening, and generate an optimized SPF record. Reduce DNS lookup pressure while keeping the resulting authorization easy to review.
✓ Recursive include expansion·✓ DNS lookup simulation·✓ Optimized SPF preview·✓ Free to use
SPF Flattening Workspace
Analyze your domain's SPF record, review its recursive lookup tree, and simulate a flattened version.
Original SPF record
TXTv=spf1 include:_spf.google.com include:spf.protection.outlook.com include:sendgrid.net a mx -allFlattened SPF record
TXTv=spf1 ip4:74.125.0.0/16 ip4:209.85.128.0/17 ip4:40.92.0.0/15 ip4:167.89.0.0/16 ip4:13.111.64.0/18 a mx -allLookup tree & expansion
View: TreeResolved IP addresses (32)
| IP address / Range | Source | Status | Notes |
|---|---|---|---|
| 74.125.0.0/16 | Included | From _spf.google.com | |
| 209.85.128.0/17 | Included | From _spf.google.com | |
| 40.92.0.0/15 | Microsoft | Included | From spf.protection.outlook.com |
| 52.100.0.0/16 | Microsoft | Included | From spf.protection.outlook.com |
| 167.89.0.0/16 | SendGrid | Included | From sendgrid.net |
| 13.111.64.0/18 | SendGrid | Included | From sendgrid.net |
About This SPF Flattener
The SPF Flattener expands include statements, simulates recursive SPF DNS lookups, resolves supported authorization sources to direct IP addresses, and produces a flattened SPF preview. This can reduce DNS-querying terms, but flattened records require maintenance when providers change their IP ranges.
What it does
- Parses your published SPF record
- Recursively expands include statements
- Simulates SPF DNS-querying terms
- Resolves supported sources to IP addresses
- Generates a flattened SPF preview
- Highlights optimization and maintenance risks
Who it’s for
- Domain owners
- IT administrators
- Email deliverability teams
- Security teams
- Agencies
- MSPs and resellers
Important to know
- SPF has a 10 DNS-querying-term limit
- Flattened records may need periodic updates
- Third-party providers can change IP ranges
- Not every SPF mechanism can be safely flattened
- Unknown DNS evidence is not a failure
- Always verify the record before publishing
How It Works
Get your SPF flattening simulation in four simple steps.
- 1Enter Domain
Type in your domain name and start the analysis.
- 2Expand Includes
Mailvovo recursively looks up supported SPF include chains.
- 3Simulate Flattening
We build a flattened preview using directly resolved authorization sources.
- 4Review & Use
Review the result carefully before publishing it in DNS.
Frequently Asked Questions
SPF flattening replaces supported recursive authorization mechanisms with direct IP address mechanisms to reduce DNS-querying terms during SPF evaluation.
A correctly maintained flattened record can preserve authorization while reducing DNS-querying terms, but stale IP ranges or an incorrect transformation can cause legitimate mail to fail SPF.
Only when the included mechanisms can be resolved and represented safely. Mailvovo highlights unresolved, unknown, or non-equivalent mechanisms that need manual review.
Not in this free simulator. The generated record is a preview and is not published or maintained automatically.
There is no universal schedule because third-party providers can change their sending infrastructure at any time. A flattened record should be monitored and regenerated when provider IP ranges change.
A very large flattened record can become difficult to maintain and may not be a good optimization strategy. In that case, consider simplifying sending services or using automated SPF management.
Try Another Domain
Check another SPF configuration and generate a fresh flattening simulation.