Fastmail vs Slab

Fastmail (Open-source software developed at Fastmail.) and Slab (Making the workplace a source of learning and purpose through knowledge-sharing. We're hiring!) both appear on the Smoower Developer Ecosystem Index.

Fastmail (rank #430) holds a narrow lead over Slab (rank #455) on the overall Smoower ecosystem score (40 vs 39). The gap of 1 points reflects composite signals across code, docs, community and reach.

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

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. Slab shows 49,433 stars across 28 public repos, 0 active in the last 90 days and 8 external contributors. The star gap on its own does not decide the comparison, but Slab's footprint is roughly 7.8x larger, which usually shows up in downstream signals like inbound issues and third party integrations.

Fastmail is the stronger read for anyone weighting reach. Slab 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.