SPF Analyzer

SPF is a method to prevent email sender address forgery.


Enter a domain to view and analyze its SPF record:


"250ok has built a best-of-breed platform that addresses the concerns of today's data-driven marketers."


Len Shneyder
VP of Industry Relations at SendGrid

Need assistance with SPF? See how 250ok can help.



More Free Tools

Blacklist Checker

Instantly check an IP or domain against major email blacklists including Spamhaus, SURBL, SORBS, and more.


Use Blacklist Checker


CIDR to IP Range

Enter a CIDR notation to instantly convert it to an IP range.


Use CIDR to IP Range

SPF Analyzer

SPF is a method to prevent email sender address forgery. Enter your domain to analyze its SPF record.


Use SPF Analyzer


IP Range to CIDR

Enter a IP range to instantly convert it to a CIDR notation.


Use IP Range to CIDR

DMARC Wizard

Enter your domain to analyze your DMARC record or create a DMARC policy for your domain.


Use DMARC Wizard


DNS Lookup

Perform a DNS lookup against multiple widely used nameservers around the world.


Use DNS Lookup

Resources for #SeriousSenders


Seedlist-based inbox monitoring 250ok Return Path eDataSource

Seedlist-Based Inbox Monitoring the Right Way

When sending commercial email, it’s important to understand what’s likely to happen the next time you send to a recipient at a particular mailbox provider. Are your messages hitting SPAM at Yahoo! or going missing at Comcast? Are you sacrificing ROI because you lack the proper visibility into performance? Seedlist-based inbox monitoring is a key […]

IP and Domain Warming, a Medieval Perspective

Marketers are often confused about the point of IP and domain warming, and they end up wondering: “Everything is authenticated, and I’m not using a blacklisted IP, so what’s the problem?” In short: senders who blast to their entire list without history look like spammers. Internet service providers (ISPs) can choose what to accept or […]

The Truth About Email Panel Data

We’re often asked about our stance on the use of email panel data. As senders, we want additional data points, visibility, and signals. In a perfect world, email panel data would enable marketers to compare their engagement to that of their competitors within a contextually relevant group of subscribers. Collected ethically and without bias, this […]




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