When comparing Gridly vs GraphCMS, the Slant community recommends GraphCMS for most people. In the question“What are the best open source headless CMS's?” GraphCMS is ranked 11th while Gridly is ranked 18th. The most important reason people chose GraphCMS is:
Webhooks enable you to trigger custom code as soon as your content changes.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Webhooks
Webhooks enable you to trigger custom code as soon as your content changes.
Pro Image processing
On-the-fly image transformations, such as resizing or cropping just by adding parameters to your media´s URL.
Pro Roles and permissions
The roles and permissions feature allows you to assign your collaborators different roles, such as Developer, Editor and Collaborator.
Pro Multi-project management
You can manage multiple projects and create up to 50 users per account to help manage those projects.
Cons
Con Not really open-source
Although there are some repositories on Github, it does not seem to be fully open-source.