Cal.com significantly outpaces Rallly in community adoption with 47,573 stars compared to 5,212 stars on GitHub. This 9.1x difference suggests Cal.com has a much larger and more active community. In terms of developer contributions, Cal.com has 14,767 forks, indicating strong developer engagement.

Cal.com is growing faster, adding 1,132 stars in the last 30 days (+2.4%) against adding 48 stars for Rallly (+0.9%). Cal.com is both larger and pulling further ahead.

Both projects show recent activity, with Cal.com last updated 6 days ago and Rallly 4 hours ago.

Both tools share common technology foundations, being built with JavaScript, CSS, Bash, Typescript, JSX, Next.js. However, they differ in their additional technology choices: Cal.com uses PHP, NestJS.

Rallly has been in development longer, starting 12 years ago, compared to Cal.com which began 5 years ago. This 6.2-year head start suggests Rallly may have more mature features and established processes.

Cal.com uses the MIT license, which is more permissive than Rallly's AGPL-3.0 license, potentially offering greater flexibility for commercial use and integration.

Both tools serve similar use cases in Appointment Scheduling.

Both Cal.com and Rallly offer self-hosting capabilities, giving you full control over your data and infrastructure.