@bun-win32/credui

Zero-dependency, zero-overhead Win32 CredUI bindings for Bun on Windows.

Overview

@bun-win32/credui exposes the credui.dll exports using Bun's FFI. It provides a single class, Credui, which lazily binds native symbols on first use. You can optionally preload a subset or all symbols up-front via Preload().

The bindings are strongly typed for a smooth DX in TypeScript.

Features

• Bun-first ergonomics on Windows 10/11.
• Direct FFI to credui.dll (credential prompts, packed authentication buffers, SSPI-assisted credential flows, and SSO helpers).
• In-source docs in structs/Credui.ts with links to Microsoft Docs.
• Lazy binding on first call; optional eager preload (Credui.Preload()).
• No wrapper overhead; calls map 1:1 to native APIs.
• Strongly-typed Win32 aliases (see types/Credui.ts).

Requirements

• Bun runtime
• Windows 10 or later

Installation

bun add @bun-win32/credui

Quick Start

import Credui from '@bun-win32/credui';

const principal = Buffer.from('CONTOSO\\alice\0', 'utf16le');
const userBuffer = Buffer.alloc((513 + 1) * 2);
const domainBuffer = Buffer.alloc((513 + 1) * 2);

const status = Credui.CredUIParseUserNameW(principal.ptr, userBuffer.ptr, 514, domainBuffer.ptr, 514);

if (status === 0) {
  const user = userBuffer.toString('utf16le').replace(/\0.*$/, '');
  const domain = domainBuffer.toString('utf16le').replace(/\0.*$/, '');
  console.log({ domain, user });
}

[!NOTE] AI agents: see AI.md for the package binding contract and source-navigation guidance. It explains how to use the package without scanning the entire implementation.

Examples

Run the included examples:

bun run example:credential-buffer-visualizer
bun run example:credential-diagnostic
bun run example:system-credential-dialog

example:system-credential-dialog opens the real Windows credential provider UI. On a Hello-enabled machine, the available tiles can include password, PIN, face, fingerprint, smart card, or other installed providers, depending on local policy and configuration.

Notes

• Either rely on lazy binding or call Credui.Preload().
• Windows only. Bun runtime required.
• SAL types & naming: nullability is in the type — Optional<T> (formally optional, SAL _*opt_) and Nullable<T> (plain [in]/[out] the docs say can be NULL), the null sentinel derived from T (null for pointers LP*/P*, 0n for handles/by-value addresses); direction is in the parameter name — _out (_Out_), _in_out (_Inout_), _In_ bare. See AI.md and the repo AGENTS.md.