Fastmail vs Mailchimp

Fastmail (Open-source software developed at Fastmail.) and Mailchimp (Mailchimp is an all-in-one marketing platform that helps you manage and talk to your clients, customers, and other interested parties.) both appear on the Smoower Developer Ecosystem Index.

Mailchimp (rank #317) holds a narrow lead over Fastmail (rank #430) on the overall Smoower ecosystem score (44 vs 40). 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), Mailchimp is ahead of Fastmail. On education (docs, guides and learning material for developers), Fastmail is ahead of Mailchimp. On community (issue response, PR reviews and discussion health), Mailchimp is slightly ahead of Fastmail. On reach (how visible the ecosystem is beyond its own repos), Fastmail is clearly ahead of Mailchimp. On momentum (release cadence and how fast the ecosystem moves), Fastmail is clearly ahead of Mailchimp.

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. Mailchimp shows 8,980 stars across 28 public repos, 6 active in the last 90 days and 6 external contributors.

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