Merlin AI puts GPT, Claude, Gemini, and more into a sidebar that follows you across the web. One extension, one subscription, and every page, inbox, and video you open gains an AI layer.

Merlin is a browser extension (plus web app) that brings multi-model AI to wherever you already are. On an article, it summarizes; on YouTube, it digests videos with timestamps; in Gmail, it drafts replies in context; on LinkedIn, it writes comments and messages; on any site, a keyboard shortcut opens chat with your chosen model. It reads PDFs, supports live web-grounded answers, and lets you switch between frontier models per task, using Claude for writing, Gemini for research, GPT for general chat.

The free tier's daily queries made Merlin one of the most installed AI extensions; the paid tier effectively replaces multiple model subscriptions with one.

Who is it for?

Knowledge workers who live in the browser, sales and recruiting professionals working LinkedIn and email, and researchers summarizing at volume, anyone for whom tab-switching to a chatbot is the friction.

How much does Merlin AI cost?

Free daily queries cover light use. Pro at around $19 per month unlocks high-volume access to all premium models, priority speed, and full features, cheaper than two separate model subscriptions.

Our verdict

Merlin is one of the best-executed AI extensions: fast, genuinely multi-model, and useful within minutes. Privacy-cautious users should review permissions, as with any extension that reads pages, but the productivity gain is real.