How do I automatically fold code based on indentation level?

Explanation

Setting foldmethod=indent tells Vim to create folds based on the indentation level of each line. Lines with deeper indentation become nested folds. This works instantly with any file — no syntax rules or markers needed.

How it works

:set foldmethod=indent
:set foldlevel=1        " Start with top-level folds open

Vim automatically groups consecutive lines at the same or deeper indentation into folds.

Fold commands

zo      " Open fold under cursor
zc      " Close fold under cursor
za      " Toggle fold under cursor
zR      " Open ALL folds in the file
zM      " Close ALL folds in the file
zr      " Reduce fold level by one (open one level)
zm      " Increase fold level by one (close one level)

Example

With Python code:

def outer():
    def inner():
        return 1
    return inner()

After :set foldmethod=indent, the inner function body becomes a fold nested inside the outer function fold.

All fold methods

Tips

• indent is the easiest fold method for Python, YAML, and other indentation-based formats
• Set foldlevelstart in your vimrc to control initial fold state:

  set foldlevelstart=99  " Start with all folds open
  

• Use syntax folding for C-like languages with braces