Affirm vs Fastmail

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

Fastmail (rank #430) holds a narrow lead over Affirm (rank #485) on the overall Smoower ecosystem score (40 vs 38). The gap of 2 points reflects composite signals across code, docs, community and reach.

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

Affirm carries 207 GitHub stars across 116 public repos, with 9 repositories active in the last 90 days and 4 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 Fastmail's footprint is roughly 30.5x larger, which usually shows up in downstream signals like inbound issues and third party integrations.

Affirm is the stronger read for anyone weighting code quality. 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.