Docstring Stub Generator

About this tool

Paste a function signature and get back a documentation stub with a slot for every parameter, the return value and the errors it raises. Nothing is uploaded — the parser is compiled to WebAssembly and runs inside your browser tab.

Ten languages are covered, each in its own convention: Python docstrings (Google, NumPy, Sphinx/reStructuredText, Epytext and PEP 257), JSDoc for JavaScript and TypeScript, PHPDoc, Javadoc, C# XML doc comments, godoc, rustdoc and Ruby YARD. Leave the language on Auto-detect and the shape of the code decides.

Parameter types come from the annotations you wrote; where there is no annotation, the default value is used as a hint (timeout = 30 → int, name = "x" → str), and anything still unknown becomes a _type_ placeholder you can replace. Set Types to Declared annotations only to suppress the guessing, or to No types for the untyped variant of each convention.

Worked example

Input:

def fetch(url: str, timeout: int = 30) -> dict:

With language = python, style = google and the default options, the output is:

def fetch(url: str, timeout: int = 30) -> dict:
    """_description_

    Args:
        url (str): _description_
        timeout (int, optional): _description_. Defaults to 30.

    Returns:
        dict: _description_
    """

Switch Language to typescript, turn Align tag columns on, and export async function load(id: string, opts?: LoadOptions): Promise<User> { produces a JSDoc block above the signature instead, with the descriptions lined up:

/**
 * _description_
 *
 * @param {string}      id     - _description_
 * @param {LoadOptions} [opts] - _description_
 * @returns {Promise<User>} _description_
 */

Set Output to Stub only for just the comment block, or to Parsed signature as JSON for a machine-readable {name, async, params, returns, raises} record — handy for feeding a codemod.

Limits and edge cases

This reads signatures, not function bodies, so it cannot know which errors a function throws: list them yourself in the Errors raised box and they become a Raises: / @throws / # Errors section. Java throws clauses are the one exception — they are read straight off the signature.

Descriptions are always placeholders. This tool does not write prose for you; it builds the scaffolding so the summary is the only thing left to type.

It is a structural parser, not a full language grammar. Destructured JavaScript parameters (function f({a, b})) are documented as a single parameter under their literal text, unnamed Go parameters are treated as names, and a trailing comment on the same line as a signature is read as part of it. Input is capped at 200,000 bytes and 200 signatures per run, with 100 parameters per signature and 20 declared error names.

FAQ