Thank you for your issue! I don't have the time to add it myself, but I would be happy to review and accept a PR adding it. 🙂 If you want to the conventions, generally all you have to do is look at octokit's API, as we try to be similar where possible so it's recognisable for developers.

Would this use the REST API for the "classic" implementation or the preferred GraphQL client?

Classic: https://docs.github.com/en/rest/projects/projects?apiVersion=2022-11-28

GraphQL: https://docs.github.com/en/issues/planning-and-tracking-with-projects/automating-your-project/using-the-api-to-manage-projects

Looking at the restful API:

Org Projects

• projects: GET /orgs/{org}/projects
• projects: POST /orgs/{org}/projects

Projects

• projects: GET /projects/{project_id}
• projects: PATCH /projects/{project_id}
• projects: DELETE /projects/{project_id}
• projects: GET /repos/{owner}/{repo}/projects
• projects: POST /repos/{owner}/{repo}/projects

User Projects

• projects: POST /user/projects
• projects: GET /users/{username}/projects

Cards

• cards: GET /projects/columns/cards/{card_id}
• cards: PATCH /projects/columns/cards/{card_id}
• cards: DELETE /projects/columns/cards/{card_id}
• cards: POST /projects/columns/cards/{card_id}/moves
• cards: GET /projects/columns/{column_id}/cards
• cards: POST /projects/columns/{column_id}/cards

Collaborators

• collaborators: GET /projects/{project_id}/collaborators
• collaborators: PUT /projects/{project_id}/collaborators/{username}
• collaborators: DELETE /projects/{project_id}/collaborators/{username}
• collaborators: GET /projects/{project_id}/collaborators/{username}/permission

Columns

• columns: GET /projects/columns/{column_id}
• columns: PATCH /projects/columns/{column_id}
• columns: DELETE /projects/columns/{column_id}
• columns: POST /projects/columns/{column_id}/moves
• columns: GET /projects/{project_id}/columns
• columns: POST /projects/{project_id}/columns

Would this use the REST API for the "classic" implementation or the preferred GraphQL client?

The REST API, if people want to use GraphQL they can through the graphql method.

Hi, I like the api, I stumbled upon it a couple of weeks ago due to a personal project. I'd like to contribute filling out some of the boxes above.

@gabrielecodes Great feel free to make a PR and I will review it when I have time 🙂

I looked at this briefly and I think the part I got confused on is that a card should be able to reference a user but the user API isn't implemented. Could that be the case or perhaps I've misunderstood?

PR #447 adds interfaces to the REST api for org projects, projects and user projects. I added mock tests. I don't have an "old" style GH project to test the (REST) api, so let me know how you want to proceed.

I looked at this briefly and I think the part I got confused on is that a card should be able to reference a user but the user API isn't implemented. Could that be the case or perhaps I've misunderstood?

I think it depends on what is needed, we do have some of the user schema such as Author already available, but obviously if we're missing other parts those need to be added too.

I don't have an "old" style GH project to test the (REST) api, so let me know how you want to proceed.

That's fine, I've approved the CI run, please do remember to un-draft your PR when you think it's ready to be merged, as I don't tend to put review time into drafts.

I fixed the doc tests, I think the PR is ready to be reviewed.