Klaviyo vs Mollie

Klaviyo and Mollie (Building a payments and banking stack for makers.) both appear on the Smoower Developer Ecosystem Index.

Mollie (rank #122) holds a narrow lead over Klaviyo (rank #237) on the overall Smoower ecosystem score (54 vs 48). The gap of 6 points reflects composite signals across code, docs, community and reach.

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

Klaviyo carries 573 GitHub stars across 117 public repos, with 23 repositories active in the last 90 days and 17 external contributors on record. Mollie shows 2,571 stars across 85 public repos, 30 active in the last 90 days and 26 external contributors. The star gap on its own does not decide the comparison, but Mollie's footprint is roughly 4.5x larger, which usually shows up in downstream signals like inbound issues and third party integrations.

Klaviyo is the stronger read for anyone weighting reach. Mollie looks better where education 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.