Customer IO vs Proton Mail

Customer IO and Proton Mail both appear on the Smoower Developer Ecosystem Index.

Customer IO (rank #165) holds a modest lead over Proton Mail (rank #401) on the overall Smoower ecosystem score (51 vs 41). The gap of 10 points reflects composite signals across code, docs, community and reach.

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

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. Proton Mail shows 16,265 stars across 186 public repos, 19 active in the last 90 days and 20 external contributors. The star gap on its own does not decide the comparison, but Proton Mail's footprint is roughly 23.8x 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. Proton Mail looks better where community is the deciding factor. The table below breaks the scores down pillar by pillar; the linked profiles cover the underlying repos, docs and community signals in full.