Customer IO vs Grammarly

Customer IO and Grammarly (Millions of users rely on Grammarly's AI-powered products to make their messages, documents, and social media posts clear, mistake-free, and impactful.) both appear on the Smoower Developer Ecosystem Index.

Customer IO (rank #165) holds a modest lead over Grammarly (rank #602) on the overall Smoower ecosystem score (51 vs 34). The gap of 17 points reflects composite signals across code, docs, community and reach.

On code quality (the state of repositories, tests, releases and polish), Customer IO is ahead of Grammarly. On education (docs, guides and learning material for developers), Customer IO is clearly ahead of Grammarly. On community (issue response, PR reviews and discussion health), Customer IO is slightly ahead of Grammarly. On reach (how visible the ecosystem is beyond its own repos), Customer IO is slightly ahead of Grammarly. On momentum (release cadence and how fast the ecosystem moves), Customer IO is ahead of Grammarly.

Customer IO carries 684 GitHub stars across 107 public repos, with 42 repositories active in the last 90 days and 26 external contributors on record. Grammarly shows 4,355 stars across 23 public repos, 0 active in the last 90 days and 0 external contributors. The star gap on its own does not decide the comparison, but Grammarly's footprint is roughly 6.4x larger, which usually shows up in downstream signals like inbound issues and third party integrations.

Customer IO is the stronger read for anyone weighting education. Grammarly makes more sense for teams already using its adjacent tools. The table below breaks the scores down pillar by pillar; the linked profiles cover the underlying repos, docs and community signals in full.