SPF Flattening ToolOversized SPF records silently break email delivery. Flatten any domain's record into a managed one that stays under the 10-lookup limit, kept current by automatic regular scanning of every provider every 30 minutes. Free to use with a Maileroo account.
Deliverability, ProtectedEvery include you add pushes your SPF record closer to the RFC 7208 limit of 10 DNS lookups. Cross it, and receiving servers can permerror your mail straight into spam. Flattening keeps you safely under the limit for good.
How It WorksThe tool does the DNS heavy lifting: resolving every include, collecting every IP, and assembling a record you can publish with confidence.
We resolve your live SPF record and walk the full include tree exactly like a receiving server would.
Every record, its depth in the tree, and the lookups it consumes, plus warnings for multiple records or unresolvable includes.
All IPs are collected into managed records, and you get a single flattened record that points at them.
Swap your old record for the flattened one. Automatic regular scanning rechecks the managed records every 30 minutes and refreshes them as providers change their infrastructure.
FAQHow SPF flattening works, why the 10-lookup limit matters, and how managed records keep your record valid.
SPF flattening replaces the includes in your SPF record with the actual IP addresses they resolve to, so the published record needs far fewer DNS lookups. Enter a domain and the tool resolves its live SPF record tree the way a receiving server would, collects every IP, and builds a flattened replacement record served from Maileroo-managed DNS. Want to see your record's lookup count first? Run it through the SPF Lookup tool, then come back to flatten it, free and unlimited, if it's over the limit.
SPF validation allows a maximum of 10 DNS-querying mechanisms per check, counting include, a, mx, ptr, exists, and redirect. If a check needs more than 10, the result is a permanent error (permerror) and receiving servers may treat your mail as unauthorized. Large providers nest includes several levels deep, which is why big records routinely exceed the limit.
Instead of pasting hundreds of IP addresses into your record, the flattened record points at Maileroo-managed DNS records that hold the IP list. Those records are rechecked against every provider every 30 minutes and refreshed whenever sending IPs change, so your published record never goes stale and never creeps over the lookup limit.
No. Once you publish the flattened record, the managed records it points to are rechecked every 30 minutes and refreshed automatically when a provider adds or removes sending IPs. Your DNS stays untouched while the underlying IP list stays current.
Yes, it's fully customizable. After the initial scan builds the flattened record, add whatever you need on top of it: your own include: mechanisms, ip4:/ip6: addresses, macros, anything a normal SPF record allows. Mechanisms that cannot be flattened safely are already carried over as-is.
Warnings are non-fatal issues, such as multiple SPF records on a domain or mechanisms that had to be simplified. Errors mean part of the include tree could not be resolved, so the flattened record may be incomplete. Either way, review them before replacing your live record.
Yes, free of cost. The SPF flattening tool requires a free Maileroo account to use, and creating one costs nothing. Once signed up, flatten any domain's SPF record, check it against the 10-lookup limit, and generate a managed replacement record without paying a cent.
Unlimited. A free Maileroo account comes with unlimited SPF flattening runs, free of cost, for every domain you manage. Each flattened record gets its own Maileroo-managed DNS records, kept current by automatic regular scanning every 30 minutes.
FeaturesEverything behind reliable delivery at any volume: sending, verification, routing, and the analytics to see what happened, from first API call to millions a month.
Send transactional and bulk emails through reliable SMTP infrastructure built for speed, security, and deliverability.
Integrate email delivery into your applications using powerful APIs built for flexibility, scalability, and performance.
Separate transactional and marketing traffic into isolated sending streams to protect reputation and keep critical emails fast.
Receive and route incoming emails directly into your applications using flexible automation and processing workflows.
Create and deliver marketing campaigns designed to increase engagement, reach, and customer retention.
Receive real-time event notifications for deliveries, opens, and clicks for storage and automation workflows.
Monitor email performance with detailed insights, reporting tools, and actionable delivery metrics in real time.
Gain greater sending control with dedicated IPs designed for consistency, reputation, scalability, and reliability.
Build integrations faster using SDKs, code examples, and resources for modern application development.
