Fastmail vs Gusto

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

Gusto (rank #338) holds a narrow lead over Fastmail (rank #430) on the overall Smoower ecosystem score (43 vs 40). The gap of 3 points reflects composite signals across code, docs, community and reach.

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

Fastmail carries 6,316 GitHub stars across 38 public repos, with 12 repositories active in the last 90 days and 2 external contributors on record. Gusto shows 781 stars across 148 public repos, 20 active in the last 90 days and 6 external contributors. The star gap on its own does not decide the comparison, but Fastmail's footprint is roughly 8.1x larger, which usually shows up in downstream signals like inbound issues and third party integrations.

Fastmail is the stronger read for anyone weighting reach. Gusto looks better where code quality 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.