Lightpanda Browser

Overview

Lightpanda is a browser built from scratch for automation, not a Chromium fork. It runs JavaScript (V8), loads pages over libcurl, builds a DOM, and speaks the Chrome DevTools Protocol (CDP) and WebDriver BiDi, so Puppeteer and Playwright can connect to it. It does not lay out or paint pages. The project reports about 16x less memory and 9x faster execution than headless Chrome on a 100-page crawl; treat that as a vendor benchmark and measure your own sites.

Version 1.0.0 (2 October 2026) has five subcommands: fetch (load URLs and dump them), serve (CDP/BiDi server), mcp (MCP server over stdio or HTTP), agent (an LLM-driven browsing REPL) and run (replay a saved script, no LLM). Older guides use a bare lightpanda --host ... --port ...; use serve instead.

Instructions

Install

Packages first, then a checksum-verified binary:

brew install lightpanda-io/browser/lightpanda        # macOS / Linux, tracks the nightly build

Release assets are listed with their SHA-256 on the GitHub release page. Verify before running:

curl -L -o lightpanda https://github.com/lightpanda-io/browser/releases/download/1.0.0/lightpanda-x86_64-linux
echo "aa5a4b8ed53d1e38b3c73f5b2647d0a84a82e6744557f45f9a9c85858aa031c3  lightpanda" | sha256sum -c
chmod +x lightpanda && ./lightpanda version

Other assets: lightpanda-aarch64-linux, lightpanda-aarch64-macos, lightpanda-x86_64-macos, and .deb packages. Linux binaries need glibc (they fail on Alpine with "required file not found"); there is no native Windows or Android build. Docker: docker run -d --name lightpanda -p 127.0.0.1:9222:9222 lightpanda/browser:nightly.

Telemetry is on by default; set LIGHTPANDA_DISABLE_TELEMETRY=true to turn it off.

Fetch a page without any client library

lightpanda fetch --dump markdown --strip-mode js https://news.ycombinator.com

--dump takes html, markdown, pdf, png (text-only rendering), semantic_tree or semantic_tree_text. Useful companions: --dump-selector "main", --strip-mode clutter|shell|css|js|invisible, --dump-max-bytes 60000, --fail-on-http-error, --json, --obey-robots, --cookie, and the --wait-until, --wait-ms, --wait-selector, --wait-script flags for pages that finish rendering late.

Serve CDP for Puppeteer or Playwright

lightpanda serve --host 127.0.0.1 --port 9222 --obey-robots

Check it with curl http://127.0.0.1:9222/json/version. Add --protocol webdriver for BiDi (repeat --protocol to serve both). Keep the host on 127.0.0.1: the endpoint has no authentication.

MCP server for agents

{ "mcpServers": { "lightpanda": { "command": "/usr/local/bin/lightpanda", "args": ["mcp"] } } }

lightpanda mcp --port 9223 serves MCP over HTTP at /mcp; each client gets its own session through the Mcp-Session-Id header.

Agent mode and scripts

lightpanda agent --task "top story on news.ycombinator.com?" drives the browser from plain English. It detects the provider from environment variables (Anthropic, OpenAI, Gemini, Vertex, Mistral, Hugging Face, OpenRouter, Vercel AI Gateway, Ollama, llama.cpp); --no-llm gives a REPL. /save (or --save out.js) writes a PandaScript, a JavaScript file you replay with lightpanda run out.js with no model calls.

Examples

Example 1: Turn a docs page into Markdown for an LLM

Request: "Get the pricing section of that page as Markdown, small enough for a prompt."

lightpanda fetch --dump markdown --dump-selector "main" --strip-mode clutter \
  --dump-max-bytes 40000 https://demo-browser.lightpanda.io/campfire-commerce/ > page.md

Result: page.md holds the main content as Markdown, cut at 40 kB with a [truncated] marker if longer.

Example 2: Scrape links with Puppeteer

Request: "List every link on the demo shop page using Puppeteer."

lightpanda serve --port 9222 &

import puppeteer from "puppeteer-core";

const browser = await puppeteer.connect({ browserWSEndpoint: "ws://127.0.0.1:9222" });
const context = await browser.createBrowserContext();
const page = await context.newPage();
await page.goto("https://demo-browser.lightpanda.io/amiibo/", { waitUntil: "networkidle0" });
const links = await page.evaluate(() =>
  Array.from(document.querySelectorAll("a")).map((a) => a.getAttribute("href")),
);
console.log(links);
await page.close();
await context.close();
await browser.disconnect();

Result: an array of href strings. Stop the server by its PID when finished.

Example 3: Playwright over CDP

import asyncio
from playwright.async_api import async_playwright

async def main():
    async with async_playwright() as p:
        browser = await p.chromium.connect_over_cdp("http://127.0.0.1:9222")
        context = await browser.new_context()
        page = await context.new_page()
        await page.goto("https://demo-browser.lightpanda.io/campfire-commerce/")
        print(await page.title())
        await browser.close()

asyncio.run(main())

Result: the page title is printed. If a Playwright call is not implemented, fall back to page.evaluate.

Guidelines

• Prefer fetch --dump markdown when you only need page text; start serve only when you need clicks, forms or a client library.
• Reuse one browser connection and open a context per task instead of reconnecting per page.
• No screenshots in the Chrome sense: png and pdf dumps are text-only renderings. Use Chromium for visual testing.
• Web API coverage is still partial (see the Web Platform Tests dashboard linked from the README). If a heavy single-page app breaks, test the same flow in Chromium before blaming your code.
• Respect robots.txt with --obey-robots, rate-limit requests, and never scrape pages behind logins you do not own.
• agent scripts and .js files run arbitrary JavaScript in pages; run only scripts you trust. LLM API keys come from environment variables such as ANTHROPIC_API_KEY.
• The licence is AGPL-3.0: check it before embedding the binary in a distributed product.