When passing the `commit_id`, use the SHA of the latest commit in the pull request or your comment may appear as "outdated" if the specified `position` has been modified in a subsequent commit.

To comment on a specific line in a file, you will need to first determine the position in the diff. GitHub offers a `application/vnd.github.v3.diff` media type which you can use in a preceding request to view the pull request's diff. The diff needs to be [interpreted](https://en.wikipedia.org/wiki/Diff_utility#Unified_format) to translate from the *line in the file* to a *position in the diff*. The `position` value is the number of lines down from the first "@@" hunk header in the file you would like to comment on. The line just below the "@@" line is position 1, the next line is position 2, and so on. The position in the file's diff continues to increase through lines of whitespace and additional hunks until a new file is reached.

{{/tip}}