Font Awesome's 99% sender score means nothing to Gmail's spam filter

Font Awesome discovered its announcement emails were quietly vanishing into Gmail spam folders despite a 99% reputation score in SendGrid. The team only noticed when preparing a Kickstarter launch and auditing recent sends. With roughly 90% of their list on Gmail addresses, the silent deliverability collapse meant a long stretch of missed product updates to paying customers.

The core problem is that Gmail operates its own opaque reputation system that ignores third-party scoring. Worse, it rewards constant volume to keep a sending IP warm, which directly punishes companies that follow the polite playbook of emailing only when there’s real news. Send too much and complaints sink your score; send too little and inactivity does the same. Either path degrades deliverability.

The remediation is unglamorous: prune stale addresses, slow the cadence, tighten authentication and list hygiene, and absorb the time cost rather than pay enterprise deliverability vendors. The episode highlights how a single mailbox provider’s private heuristics can override every industry signal and effectively dictate sender behavior across the web.