Fastmail vs Zscaler, Inc.

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

Zscaler, Inc. (rank #298) holds a narrow lead over Fastmail (rank #430) on the overall Smoower ecosystem score (45 vs 40). The gap of 5 points reflects composite signals across code, docs, community and reach.

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

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. Zscaler, Inc. shows 337 stars across 58 public repos, 33 active in the last 90 days and 11 external contributors. The star gap on its own does not decide the comparison, but Fastmail's footprint is roughly 18.7x larger, which usually shows up in downstream signals like inbound issues and third party integrations.

Fastmail is the stronger read for anyone weighting reach. Zscaler, Inc. 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.