Ferrum review
A focused, open-source Ruby interface for Chromium automation through CDP.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Ferrum is an open-source Ruby library for controlling Chrome and Chromium through the Chrome DevTools Protocol. It is aimed at developers building browser automation, testing, scraping, screenshots, JavaScript execution, network inspection, and interactive page control. The library runs headless by default and also supports headful operation, while avoiding Selenium, WebDriver, and ChromeDriver. It is distributed as a Ruby gem and can work with Capybara through the related Cuprite driver.
The pricing model is straightforward: Ferrum is open source, with no paid tiers to compare. That makes the product a fit for teams seeking a Ruby-based library they can incorporate into their own environment rather than a hosted browser execution service. Its setup model centers on the Ruby gem and a Chrome or Chromium browser, with CDP providing the control layer. Capybara users also have a related Cuprite path for browser-driven application workflows.
Ferrum’s strongest distinction is the breadth of control available within one engine. Developers can manage pages and browser sessions, take screenshots, evaluate or inject JavaScript, inspect network traffic, intercept requests, automate mouse and keyboard input, and work with multiple pages and contexts. Thread-safe execution extends that control to concurrent Ruby workflows. The trade-off is scope: Ferrum focuses on Chrome and Chromium rather than multiple browser engines. Ruby teams that want direct CDP control of Chromium should choose it; teams requiring broader engine coverage should consider an alternative.
Ferrum pros and cons
- Where it wins
- Controls Chrome and Chromium through CDP without Selenium or ChromeDriver
- Covers navigation, screenshots, JavaScript, network inspection, and input
- Supports multiple pages, contexts, and thread-safe execution
- Where it doesn't
- Supports one browser engine: Chrome and Chromium
- Requires Ruby and a Chromium-based browser environment
- No official paid pricing or hosted execution plan
Ferrum fact sheet, pricing and score →
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