Cybersource vs Fastmail

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

Fastmail (rank #430) holds a narrow lead over Cybersource (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), Cybersource is ahead of Fastmail. On education (docs, guides and learning material for developers), Fastmail is slightly ahead of Cybersource. On community (issue response, PR reviews and discussion health), Fastmail is slightly ahead of Cybersource. On reach (how visible the ecosystem is beyond its own repos), Fastmail is clearly ahead of Cybersource. On momentum (release cadence and how fast the ecosystem moves), Fastmail is slightly ahead of Cybersource.

Cybersource carries 587 GitHub stars across 40 public repos, with 28 repositories active in the last 90 days and 7 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 10.8x larger, which usually shows up in downstream signals like inbound issues and third party integrations.

Cybersource 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.