Keycloak leads in popularity with 36,125 stars vs 14,700 stars for Zitadel. The 146% higher star count indicates stronger community adoption. In terms of developer contributions, Keycloak has 8,766 forks, indicating strong developer engagement.

Zitadel is growing faster, adding 309 stars in the last 30 days (+2.1%) against adding 509 stars for Keycloak (+1.4%). Zitadel is the smaller project of the two, so it is closing the gap rather than extending a lead.

Both projects show recent activity, with Keycloak last updated 1 hour ago and Zitadel 3 hours ago.

Both tools share common technology foundations, being built with JavaScript, CSS, Bash, Typescript, JSX. However, they differ in their additional technology choices: Keycloak uses Python, C, Java while Zitadel leverages Next.js, SCSS, Golang, Lua.

Keycloak has been in development longer, starting 13 years ago, compared to Zitadel which began 6 years ago. This 6.8-year head start suggests Keycloak may have more mature features and established processes.

The projects use different licenses: Keycloak is licensed under Apache-2.0 while Zitadel uses AGPL-3.0. Consider the licensing requirements when choosing for your project.

Both tools serve similar use cases in Authentication & SSO, Authorization & Permissions.

Zitadel provides self-hosting options for complete data control and customization, while Keycloak may be primarily cloud-based or require different deployment approaches.