Selenium vs Steel

Selenium

Selenium is stable, Apache-2.0 software on 4.51.0 with bindings in five languages, CI passing on trunk, an llms.txt and an agent guide added in September 2026. It has no MCP server of its own, Selenium Manager sends usage statistics by default, and Grid accepts unauthenticated sessions unless a username and password are set.

Steel

The hosted API has a public OpenAPI document, per-unit prices, $30 of starting credit and x402 payment for scrape, screenshot and PDF calls. The status page records three API or session-creation incidents of more than an hour in 90 days, and the documented CDP connection puts the API key in the URL.

Selenium

1. Install with pip install selenium (Python 3.10 or later) and let Selenium Manager fetch drivers. Do not set driver paths
2. Use WebDriverWait with expected conditions, never fixed sleeps, and do not mix implicit and explicit waits
3. Set SE_AVOID_STATS=true to stop Selenium Manager sending usage statistics
4. Point coding agents at https://www.selenium.dev/llms.txt. Most Selenium 2 and 3 era examples use removed APIs
5. Set --username and --password before exposing a Grid beyond localhost. Check http://localhost:4444/status before creating sessions

Steel

1. Use POST /v1/scrape for pages you only need to read. It starts no session and costs $5 per 1,000 calls, or $0.01 a call by x402
2. Release every session with POST /v1/sessions/{id}/release and set inactivityTimeout. Browser time bills by the minute, rounded up
3. Build the CDP URL as wss://connect.steel.dev?apiKey=<key>&sessionId=<id> and keep it out of logs, because it carries the key
4. Launch sessions end after 15 minutes at most, and timeout cannot be changed on a live session
5. CAPTCHA solving and Steel's managed proxies on Launch need $10 of paid balance. Free credit does not count