Deezer vs Fastmail

Deezer and Fastmail (Open-source software developed at Fastmail.) both appear on the Smoower Developer Ecosystem Index.

Fastmail (rank #430) holds a narrow lead over Deezer (rank #536) on the overall Smoower ecosystem score (40 vs 36). The gap of 4 points reflects composite signals across code, docs, community and reach.

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

Deezer carries 29,854 GitHub stars across 99 public repos, with 5 repositories active in the last 90 days and 2 external contributors on record. Fastmail shows 6,316 stars across 38 public repos, 12 active in the last 90 days and 2 external contributors. The star gap on its own does not decide the comparison, but Deezer's footprint is roughly 4.7x larger, which usually shows up in downstream signals like inbound issues and third party integrations.

Deezer is the stronger read for anyone weighting community. Fastmail looks better where reach 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.