Google Mariner Adds Limited Firefox Support

Google added limited Firefox support to Project Mariner this week, marking the first time the research agent has been available outside Chrome. The support is currently labeled "experimental" and lacks some of Chrome's deeper integrations, but it works for the core research workflows Mariner is known for.

What works

In our testing, the Firefox version of Mariner handles:

• Multi-tab research with parallel source gathering
• Citation-quality synthesis across sources
• Access to logged-in subscription content (paywalled news, academic databases)
• Multi-source comparison and synthesis

What doesn't work yet

• Deep integration with Google's search graph (Firefox version uses standard search)
• Some Chrome-specific features like Google Workspace integration
• Performance is roughly 20% slower than Chrome version
• No support for Firefox's container tabs

Should Firefox users switch?

If you've been using Firefox and maintaining a Chrome installation just for Mariner, the new support is good news — you can now do most Mariner workflows in Firefox. The 20% performance hit and missing Google integrations are real but manageable for most research workflows.

For Chrome users, there's no reason to switch. The Chrome version remains the more polished and performant option. The Firefox support is mainly a win for users who prefer Firefox for privacy or extension reasons.

What this means

The Firefox support signals that Google is positioning Mariner as a cross-browser tool rather than a Chrome-exclusive feature. This matters for adoption — many privacy-conscious users and enterprises standardize on Firefox, and the Chrome-only limitation was a real barrier. We expect Google to continue improving Firefox support and eventually add Edge and Safari support as well.

For Mariner subscribers who've been waiting for Firefox, the experimental support is worth trying. For everyone else, this is a positive signal about Mariner's future direction but doesn't change the current recommendation.