SPF Record Too Long
DNS TXT records have practical length limits. While the theoretical maximum is around 255 characters per string, many DNS providers and protocols use 255-character chunks. SPF records that exceed these limits can be truncated, split incorrectly, or rejected. When that happens, receivers may not see your full policy, and SPF evaluation can fail or return unexpected results.
One-Minute Fix
Shorten your SPF record by removing obsolete providers, flattening includes to IP ranges where appropriate, and consolidating redundant mechanisms.
v=spf1 include:_spf.google.com include:sendgrid.net ~allKeeping the record under 255 characters per TXT string avoids truncation. Use flattening or provider consolidation when you have many includes.
Re-checkWrong vs correct setup
Overlong SPF record
v=spf1 include:_spf.google.com include:sendgrid.net include:mailgun.org include:amazonses.com include:spf.protection.outlook.com include:_spf1.constantcontact.com include:spf.mtasv.net ~allThis record may exceed safe TXT length and can be truncated by some DNS systems. Long records also increase the risk of exceeding the SPF lookup limit.
Consolidated record
v=spf1 include:_spf.google.com include:sendgrid.net ~allA shorter record with only active providers stays within DNS limits and is easier to maintain.
Why this happens
Domains accumulate include mechanisms over time as they add ESPs, marketing tools, and relays. Each new provider adds more characters. Eventually the record grows past DNS chunk limits or becomes hard to manage.
Why this is a problem
- Truncated records may omit critical mechanisms, causing SPF to fail for legitimate senders.
- Some DNS providers reject or mishandle very long TXT records.
- Long records often correlate with high lookup counts, increasing permerror risk.
- Maintenance becomes harder as the record grows.
How this affects deliverability
When an SPF record is truncated or malformed due to length, receivers may see an incomplete or invalid policy. That can break authentication and hurt deliverability. Shortening the record and keeping it within DNS limits restores reliable SPF evaluation.
Common causes
- Several ESPs and marketing platforms were added over time.
- Legacy providers remained in SPF after they stopped sending.
- IP ranges were added manually instead of using shorter includes.
- No one reviewed total record length after adding new services.
What we checked
We measured the length of your SPF record and whether it fits within typical DNS TXT limits. Records that exceed safe length or are split across too many strings may cause parsing issues.
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FAQ
What is the maximum SPF record length?
DNS TXT strings are typically limited to 255 characters per string. SPF can use multiple strings, but long records increase truncation and lookup risks.
Should I flatten includes to shorten the record?
Flattening can shorten the visible record, but flattened IPs can become stale. Prefer removing obsolete providers first; flatten only when necessary.
Can I split SPF across multiple TXT records?
No. SPF allows one logical record that may be split into multiple DNS strings, but you cannot have multiple SPF policies. Merging into one record is required.
Next steps
- List every provider that actually sends mail for your domain.
- Remove obsolete includes and IP mechanisms.
- Consider flattening only if cleanup is not enough.
- Keep the record under 255 characters per string where possible.
- Re-check SPF after changes to confirm the record is valid and complete.
- Review the full troubleshooting guidance in the SPF Hub.
- Check signing and selector issues in the DKIM Hub.
- Review alignment and policy issues in the DMARC Hub.