One-click ChatGPT, Claude, and Gemini in your browser sidebar. 1M+ users.
Merlin is the Chrome extension that opens a sidebar with ChatGPT, Claude, Gemini, or Llama on any page. Highlight text on a webpage → click the Merlin icon → "summarize this," "reply to this email," "rewrite this tweet." The free tier gives 51 queries/day across all models. Pro is $19/mo for unlimited access to premium models. Also has YouTube summarizer, blog post generator, and social media reply tools.
Who it's for: Anyone who wants ChatGPT-style help on every page without copy-pasting. Sales reps drafting emails in Gmail. Marketers writing social replies. Students summarizing YouTube lectures. Less ideal if you want a fully free tool — Harpa with BYO API keys is cheaper long-term.
GPT-4o, GPT-5, Claude 4.5 Sonnet, Gemini 2.5 Pro, Llama 4, Mistral — all from one extension. Switch models per task. Premium models cost more credits.
More generous than ChatGPT's free tier (which is GPT-4o mini only). 51 free queries per day on GPT-3.5-class models, enough for casual users. Pro is unlimited premium.
One-click summary of any YouTube video with timestamps. Pulls transcript, summarizes, gives you the key points in 30 seconds. Huge time-saver for research.
Native iOS, Android, Mac, and Windows apps in addition to the browser extension. Your chat history syncs across devices. Free tier available on all platforms.
Merlin is the easiest on-ramp to browser AI in 2026. If you've never used a browser AI extension, start here — the free tier is enough to feel the value in 5 minutes. The YouTube summarizer alone is worth installing. For power users, Harpa with BYO API keys is cheaper for heavy use. For everyone else, Merlin is the right default.