Incident
SendGrid IP Reputation: What Goes Wrong and How to Fix It
SendGrid shared IP pools have experienced periodic reputation issues that affect deliverability for all users on those IPs. Using dedicated IPs and configuring domain authentication properly reduces this risk.
On a shared pool, someone else's bad mail becomes your problem — Gmail and Yahoo weight domain reputation when DMARC aligns, but a toxic IP still hurts. Here's how shared IP risk shows up and how to harden your setup.
Shared IP risk on SendGrid
SendGrid, like all major ESPs, uses shared IP pools for free and low-volume accounts. If other senders on your shared IP damage its reputation, your emails are affected too.
Signs of shared IP reputation issues
- Deliverability drops suddenly without changes to your setup
- Gmail Postmaster Tools shows IP reputation declining
- Bounce rates increase without changes to your list
How to protect yourself
- Configure domain authentication properly — DKIM and DMARC alignment means your domain's reputation matters more than the shared IP
- Consider a dedicated IP if you send over 100,000 emails/month
- Monitor your domain reputation in Gmail Postmaster Tools
Domain authentication is your moat: With proper DMARC alignment, major providers weight your domain reputation heavily. Even on a shared IP, a clean domain reputation protects you.
Check SendGrid alignment
Open DNS Preflight →FAQ
Can SendGrid shared IPs affect my deliverability?
Yes. If other senders on your shared IP send spam, it damages the IP's reputation and affects everyone on that pool.
How do I know if shared IP reputation is causing my problem?
Check Gmail Postmaster Tools — it shows both IP and domain reputation separately. If IP reputation is low but domain is fine, it's the shared IP.
Should I get a dedicated SendGrid IP?
Consider it if you send 100,000+ emails/month. Below that, the warm-up period for a new dedicated IP often causes more problems than shared IP reputation.
Does configuring DMARC help with shared IP issues?
Yes. DMARC alignment shifts reputation signals to your domain rather than the sending IP. Providers weight domain reputation heavily.
How do I set up DMARC alignment for SendGrid?
Add three CNAME records from SendGrid's Sender Authentication dashboard. See the SendGrid DMARC fix guide.