Browser Use

agent37-hermes browses the web out of the box with a Chromium inside the instance. To run that browser on Browser Use Cloud instead, put your Browser Use API key in the instance’s environment. Hermes picks it up by itself: the agent keeps the same browser tools, and pages load in a Browser Use cloud browser with its stealth and residential proxies.

Paste this into your coding agent

Read https://www.agent37.com/docs/llms-full.txt.
I want my Hermes agents to browse on Browser Use Cloud.
Create an agent37-hermes instance with BROWSER_USE_API_KEY and TMPDIR=/tmp in its env and a budget, then ask it in chat to open https://ipinfo.io/json with its browser tool.
Done when the org the agent reports is a consumer internet provider, not a cloud or hosting company.
My Agent37 key is in AGENT37_API_KEY and my Browser Use key is in BROWSER_USE_API_KEY.

Create an instance with Browser Use

Get an API key from cloud.browser-use.com and pass it as BROWSER_USE_API_KEY, with TMPDIR set to /tmp:

curl -X POST https://api.agent37.com/v1/instances \
  -H "Authorization: Bearer sk_live_..." \
  -H "Content-Type: application/json" \
  -d '{
    "template": "agent37-hermes",
    "env": { "BROWSER_USE_API_KEY": "bu_...", "TMPDIR": "/tmp" },
    "budget": { "monthly_cap_micros": 5000000 }
  }'

That is the whole setup: no Hermes config, no custom image. TMPDIR works around a Hermes bug that makes cloud browser sessions fail when Hermes keeps its temp files under the home directory (hermes-agent#122786); without it the browser tool fails and the agent falls back to fetching pages without a browser. Like every env value, the key is write-only: it lives in the instance and is never returned by the API.

Add it to an existing instance

Edit the environment, then restart so the agent starts with the new values:

curl -X PATCH https://api.agent37.com/v1/instances/ab12cd34ef \
  -H "Authorization: Bearer sk_live_..." \
  -H "Content-Type: application/json" \
  -d '{ "env": { "BROWSER_USE_API_KEY": "bu_...", "TMPDIR": "/tmp" } }'

curl -X POST https://api.agent37.com/v1/instances/ab12cd34ef/restart \
  -H "Authorization: Bearer sk_live_..."

Waking a sleeping instance does not pick up the change; restart it. To go back to the built-in browser, set BROWSER_USE_API_KEY to null and restart.

Check it works

Ask the agent to open an IP lookup page with its browser tool:

curl https://ab12cd34ef.agent37.app/v1/responses \
  -H "X-Agent37-Key: sk_live_..." \
  -H "Content-Type: application/json" \
  -d '{ "input": "Open https://ipinfo.io/json with your browser tool and tell me the ip and org fields." }'

An org that is a consumer internet provider (Charter, Comcast, and the like) means the page loaded through Browser Use’s residential proxy. A cloud or hosting company means it did not: either the browser ran inside the instance, or the agent fetched the page without a browser. The session also appears in your Browser Use dashboard.

How sessions behave

One browser per turn. Each chat turn that browses opens its own cloud browser, and Hermes closes it when the turn ends, so you pay Browser Use only for the minutes a turn spends browsing. A page or sign-in does not carry over to the next turn.
Fallback to the instance. If Browser Use won’t start a browser, for example because the account is out of credits or already has as many browsers open as its plan allows, Hermes loads the page in the instance’s own Chromium and the turn still completes.

Many agents on one key

For a product where every user gets their own agent, the same key can go into every instance. Your Browser Use plan’s concurrent session limit caps how many agents can browse at the same moment, so size it to peak simultaneous browsing, not to user count. Browser Use bills browser time and proxy traffic to that account; the model and the instance bill to your Agent37 wallet as usual.

Browser Use Cloud or the built-in browser

	Built-in Chromium	Browser Use Cloud
Setup	None	Two `env` values
Cost	Included in the instance	Billed by Browser Use (pricing)
Visits from	The instance’s datacenter IP	Residential proxies
Bot checks and CAPTCHAs	Often blocked	Stealth browser and CAPTCHA solving

Use the built-in browser for sites that don’t fight automation, and Browser Use Cloud when the sites your agents visit block datacenter traffic. To watch the built-in browser work and take over a sign-in, see Browser and desktop.

Get started

Sandboxes

Agent templates

Build with Agent37

Create an instance with Browser Use

Add it to an existing instance

Check it works

How sessions behave

Many agents on one key

Browser Use Cloud or the built-in browser

​Create an instance with Browser Use

​Add it to an existing instance

​Check it works

​How sessions behave

​Many agents on one key

​Browser Use Cloud or the built-in browser

Create an instance with Browser Use

Add it to an existing instance

Check it works

How sessions behave

Many agents on one key

Browser Use Cloud or the built-in browser