GitHub API - Get the number of branches of a repo without listing all its branches

There's no such attribute currently.

However, there's a neat trick you can use to avoid fetching all pages. If you set per_page to 1, then each page will contain 1 item and the number of pages (revealed by the last page) will also tell you the total number of items:

https://developer.github.com/v3/#pagination

So, with just one request -- you can get the total number of branches. For example, if you fetch this URL and inspect the Link header:

https://api.github.com/repos/github/linguist/branches?per_page=1

then you'll notice that the Link header is:

Link: <https://api.github.com/repositories/1725199/branches?per_page=1&page=2>; rel="next", <https://api.github.com/repositories/1725199/branches?per_page=1&page=28>; rel="last"

This tells you that there are 28 pages of results, and because there is one item per page -- the total number of branches is 28.

Hope this helps.

You can also use GraphQL API v4 to get branch count easily :

{
  repository(owner: "google", name: "gson") {
    refs(first: 0, refPrefix: "refs/heads/") {
      totalCount
    }
  }
}

Try it in the explorer

which gives :

{
  "data": {
    "repository": {
      "refs": {
        "totalCount": 13
      }
    }
  }
}

As you are doing this on multiple repo, it's also more straightforward with GraphQL as you can build the query with different aliases per repo & use only one request to get branch count for all of these :

{
  fetch: repository(owner: "github", name: "fetch") {
    ...RepoFragment
  }
  hub: repository(owner: "github", name: "hub") {
    ...RepoFragment
  }
  scientist: repository(owner: "github", name: "scientist") {
    ...RepoFragment
  }
}

fragment RepoFragment on Repository {
  refs(first: 0, refPrefix: "refs/heads/") {
    totalCount
  }
}

Try it in the explorer