Lightpanda is now a browser backend in Hermes Agent

Katie Brown

Cofounder & COO

TL;DR

Lightpanda is now an officially supported browser backend in Hermes Agent  by Nous Research. One config line to enable it, with automatic Chrome fallback for anything Lightpanda can’t handle yet. Median 1.2x faster cold starts than Chrome across 27 tests, up to 4.5x on lighter sites. Here’s why it’s a good fit and how to set it up.

What is Hermes Agent

Hermes is Nous Research’s open source autonomous agent. It runs on a $5 VPS and builds persistent memory, writes its own skills when it solves hard problems, spawns subagents in parallel, and reaches you on Telegram or Discord while it works on a VM you never SSH into. The kind of agent that runs for weeks on cheap infra and slowly gets better.

If your agent is meant to live on a server for weeks, every byte of memory and every second of cold start cost adds up.

Why this integration matters

Until now, when Hermes needed to browse the web, it was driving Chrome. Running Chrome is a 200MB process and seconds of cold start, which are baggage you don’t need when the work is navigating DOMs and reading content.

Lightpanda was built from scratch in Zig for exactly this workload. Headless, no rendering pipeline, instant startup, low memory footprint. It’s a browser shaped like an agent.

The Hermes team ran a benchmark PR (#7144 ) of Chrome against Lightpanda. 27 cold-start tests across 9 sites. Lightpanda was a median 1.2x faster, averaging 1.7x. On lighter sites like example.com, react.dev, and docs.python.org, it was 2.5 to 4.5x faster.

Cold start matters more than people think. Agents don’t always have a warm browser sitting around. They spin up, do a task, and shut down. Multiply that across thousands of tasks per day and the seconds add up to hours.

How it works

Hermes uses agent-browser  to drive whichever browser engine you’ve configured. The PR adds three engine options:

• auto (default): Chrome
• lightpanda: Lightpanda, with automatic Chrome fallback for screenshots and failed commands
• chrome: Chrome explicitly

When you set engine: lightpanda, Hermes passes --engine lightpanda through to the browser layer. Hermes also adds a fallback: if a command fails on Lightpanda, or if you call something Lightpanda doesn’t yet support (like screenshots, since it has no graphical renderer), Hermes transparently retries with Chrome.

You get the speed and footprint of Lightpanda for agent work that’s just navigation and DOM scraping, and Chrome steps in for the edge cases.

Setting it up

Three steps.

1. Update Hermes to v0.13.0 or later

hermes update

If you don’t have Hermes installed yet:

curl -fsSL https://raw.githubusercontent.com/NousResearch/hermes-agent/main/scripts/install.sh | bash

2. Install the Lightpanda binary

Download the nightly build for your platform (docs here ) and put it somewhere on your PATH.

For Apple Silicon Macs:

curl -L -o lightpanda https://github.com/lightpanda-io/browser/releases/download/nightly/lightpanda-aarch64-macos
chmod +x lightpanda
sudo mv lightpanda /usr/local/bin/

3. Tell Hermes to use it

Open ~/.hermes/config.yaml, find the browser: block, and add engine: lightpanda:

browser:
  engine: lightpanda

Confirm it worked

Start Hermes and run the /browser slash command:

hermes
/browser

You should see:

🌐 Browser: local Lightpanda (agent-browser --engine lightpanda)
   ⚡ Lightpanda: faster navigation, no screenshot support
   Automatic Chrome fallback for screenshots and failed commands

What works, what doesn’t yet

Lightpanda doesn’t cover everything Chrome does. The Hermes integration draws a clear line around what’s safe to use today.

Works on Lightpanda: open, snapshot, click, type, scroll, back, press, eval. The whole core agent workflow.

Auto-fallback to Chrome: screenshots (Lightpanda has no graphical renderer), PDF generation, and any command Lightpanda errors on.

Not supported yet: file uploads, multi-tab contexts, clipboard, geolocation emulation, network condition emulation.

For most agent workflows like crawling, scraping, and automation against real websites, the supported set is enough.

What’s next

We’ll keep closing Lightpanda’s gaps with Chrome’s website coverage. Multi-context support and file uploads are the next priorities. The Hermes integration gave us a really clear picture of which gaps matter most in practice.

If you’re building agents and want a browser that doesn’t fight you on memory and startup, give it a try. If you find something broken, open an issue . If you want to see how Hermes wired it in, the PR  is a good read.

Try it now

Get started with the quickstart guide  to run your first Lightpanda script in under 10 minutes. Read the documentation  or jump straight to the Hermes integration .

Thanks to Kshitij , and the whole Nous Research team for shipping this. Lightpanda is on GitHub  and Hermes is on GitHub .

Katie Brown

Cofounder & COO

Katie led the commercial team at BlueBoard, where she met Pierre and Francis. She rejoined them on the Lightpanda adventure to lead GTM and to keep the product closely aligned with what developers actually need. She also drives community efforts and, by popular vote, serves as chief sticker officer.