{"id":3325,"library":"yt-dlp-ejs","title":"yt-dlp External JavaScript Solver","description":"yt-dlp-ejs is a specialized Python library that provides external JavaScript execution capabilities for yt-dlp, the popular video downloader. It solves YouTube's signature and n-parameter challenges by bundling JavaScript solvers that work across multiple runtimes such as Deno, Bun, Node.js, and QuickJS. Currently at version 0.8.0, it maintains a frequent release cadence to adapt to YouTube's player code changes.","status":"active","version":"0.8.0","language":"en","source_language":"en","source_url":"https://github.com/yt-dlp/ejs","tags":["yt-dlp","video-downloader","youtube","javascript","decryption"],"install":[{"cmd":"pip install yt-dlp-ejs","lang":"bash","label":"Install yt-dlp-ejs"},{"cmd":"pip install \"yt-dlp[default]\"","lang":"bash","label":"Install yt-dlp with EJS support"}],"dependencies":[{"reason":"This library is a companion package for yt-dlp, providing essential JavaScript challenge-solving capabilities for YouTube. yt-dlp will automatically detect and use it.","package":"yt-dlp"},{"reason":"An external JavaScript runtime (Deno is recommended) must be installed on the system for yt-dlp-ejs to execute the solver scripts. Not a Python package dependency.","package":"Deno / Node.js / Bun / QuickJS","optional":true}],"imports":[{"note":"Typically, end-users do not directly import this library; yt-dlp uses it automatically. This import is for advanced use cases like custom video extractors or direct interaction with solver APIs.","symbol":"yt_dlp_ejs.yt.solver","correct":"import yt_dlp_ejs.yt.solver"}],"quickstart":{"code":"import os\nfrom yt_dlp import YoutubeDL\n\n# yt-dlp-ejs is automatically detected by yt-dlp if installed.\n# Ensure a JS runtime (Deno, Node.js, Bun) is available in your PATH\n# or specified via yt-dlp options (e.g., --js-runtimes deno:/path/to/deno)\n\n# Example: Download a YouTube video that requires signature/n-parameter decryption\n# For this to work, yt-dlp-ejs and a JS runtime must be correctly set up.\n\nurl = 'https://www.youtube.com/watch?v=dQw4w9WgXcQ' # Example URL\n\nwith YoutubeDL({'format': 'bestvideo[ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best'}) as ydl:\n    info = ydl.extract_info(url, download=False)\n    print(f\"Title: {info.get('title')}\")\n    print(f\"Uploader: {info.get('uploader')}\")\n    print(f\"Duration: {info.get('duration_string')}\")\n    print(\"yt-dlp-ejs (and a JS runtime) was implicitly used for decryption.\")\n\n# To explicitly verify the presence of EJS solvers (for advanced debugging)\ntry:\n    from yt_dlp_ejs.yt.solver import core, lib\n    print(\"yt_dlp_ejs solvers (core, lib) are importable.\")\n    # Example of accessing a solver, though not typically done by end-users:\n    # core_js = core()\n    # print(f\"Core solver JS size: {len(core_js)} bytes\")\nexcept ImportError:\n    print(\"yt_dlp_ejs solvers are not directly importable or installed.\")","lang":"python","description":"This quickstart demonstrates how yt-dlp-ejs is used implicitly by yt-dlp to decrypt YouTube video URLs. No explicit Python code is usually needed to interact with yt-dlp-ejs directly when using yt-dlp. It also includes a check for direct import for debugging purposes."},"warnings":[{"fix":"Always install/update yt-dlp-ejs concurrently with yt-dlp, preferably by installing `yt-dlp[default]` or ensuring versions match the `yt-dlp`'s `pyproject.toml` definition. `pip install -U yt-dlp yt-dlp-ejs` is recommended.","message":"yt-dlp is often pinned to a specific compatible version of yt-dlp-ejs. Using mismatched versions can lead to 'No suitable player found' or 'Signature/n-parameter decryption failed' errors, especially for YouTube videos.","severity":"breaking","affected_versions":"All versions"},{"fix":"Install a supported JavaScript runtime (Deno is highly recommended) and ensure it's accessible in your system's PATH. You can also specify the runtime path using yt-dlp's `--js-runtimes` option (e.g., `--js-runtimes deno:/path/to/deno`).","message":"yt-dlp-ejs *requires* an external JavaScript runtime (e.g., Deno, Node.js, Bun, or QuickJS) to be installed on your system. Without one, yt-dlp-ejs cannot function, and YouTube support in yt-dlp will be limited or broken.","severity":"gotcha","affected_versions":"All versions"},{"fix":"Regularly update `yt-dlp` and `yt-dlp-ejs` to their latest versions to ensure compatibility with YouTube's most recent player changes. `pip install -U yt-dlp yt-dlp-ejs`.","message":"YouTube frequently updates its player code, which can break yt-dlp-ejs's decryption logic. This necessitates frequent updates to yt-dlp-ejs.","severity":"gotcha","affected_versions":"All versions"},{"fix":"Review the `yt-dlp-ejs` changelog and ensure your custom JavaScript or integration code is compatible with the changes in global scope handling if directly calling the internal solver scripts.","message":"If building from source or performing advanced integrations, be aware that internal changes (like exposing `window` as `self` in 0.8.0 or making `window` a local in 0.2.0) might affect custom JavaScript code relying on these globals.","severity":"gotcha","affected_versions":"0.2.0+, 0.8.0+"}],"env_vars":null,"last_verified":"2026-04-11T00:00:00.000Z","next_check":"2026-07-10T00:00:00.000Z"}