How to assign an issue to a project for an organisation via API?

[ThePJhayes]

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As the title says, having issues assigning an issue to a project via API. I constantly get the below response, any advise on what might be causing this would be appreciated - I can find the projects in a list function, just when trying to assign the item does it start returning the error.

"body": {
"message": "Not Found",
"documentation_url": "https://docs.github.com/rest/projects/items#add-item-to-organization-owned-project",
"status": "404"

[yoter-k]

When you get a 404 Not Found while adding an issue to a project, it usually means the API endpoint or permissions don’t match the project type.

The 404 Not Found error when assigning an issue to a project via API usually happens for one of these reasons:

1. Wrong project type or endpoint

• GitHub has both classic Projects and Projects (v2 / beta).
• The REST endpoint you’re using (/projects/items) only works for Projects v2 (organization-owned).
• Check which type your project is — if it’s a classic project, use the classic API:
  POST /projects/columns/:column_id/cards

2. Missing permissions or token scopes
   Your PAT must include:

• project or project:write
• repo (if the project is linked to a repository)
• org:write (if it’s an org-level project)

3. Incorrect project ID or issue format
   For Projects (v2), you need the node_id of both the project and the issue.
   Example GraphQL mutation:

mutation {
  addProjectV2ItemById(input: {
    projectId: "PVT_kwDOExample123",
    contentId: "I_kwDOExample456"
  }) {
    item {
      id
    }
  }
}

✅ TL;DR

• Check if it’s a classic or v2 project.
• Use the correct endpoint or GraphQL mutation.
• Make sure your token includes the required scopes.

[Loser644]

The solution will be remove the project locally and clone it again using (git clone ) then try again. This only happing because API endpoint or permissions don’t match the project type. A fresh restart will fix it