SPF Record
An SPF (Sender Policy Framework) record is a DNS TXT record that specifies which mail servers are authorised to send email on behalf of your domain.
What Is SPF Record?
SPF works by listing the IP addresses and servers permitted to send mail from your domain. When a receiving server gets an email claiming to be from your domain, it checks your SPF record to verify the sending server is authorised. If the sending server isn't listed, the email may be rejected or flagged as spam. SPF records use a specific syntax — for example, 'v=spf1 include:send.resend.com ~all' authorises Resend to send on your behalf while soft-failing all other sources.
Why It Matters for Newsletters
Without SPF, anyone can spoof your domain and send emails that appear to come from you. For newsletter creators, a properly configured SPF record is the first line of defence against spoofing and a baseline requirement for good deliverability. Most ISPs now require SPF as a minimum authentication standard.
Best Practices
- Always include your email service provider's servers in your SPF record
- Use 'include' mechanisms rather than listing individual IP addresses
- Keep your SPF record under 10 DNS lookups to avoid exceeding the lookup limit
- Use ~all (soft fail) or -all (hard fail) at the end of your record
- Combine SPF with DKIM and DMARC for comprehensive authentication
How Aldus Handles This
When you set up a custom sending domain in Aldus, the platform generates the exact SPF record you need and walks you through adding it to your DNS. Aldus uses Resend as its sending infrastructure, so your SPF record simply needs to include Resend.