Merlin
Browser extension that puts GPT and Claude in the sidebar of any page, with built-in chat history.
Merlin is a browser extension that puts GPT and Claude in the sidebar of any page, with built-in chat history. Runs as a browser extension that overlays GPT and Claude in a sidebar on any webpage.
About Merlin
Merlin is a browser extension that puts GPT and Claude in a sidebar on any webpage, with built-in chat history.
It overlays both OpenAI GPT and Anthropic Claude in one sidebar interface, so you can use either model on any page and review past conversations from built-in history.
It fits people who want an AI assistant beside whatever they are reading, on a freemium plan with free use plus paid upgrades. It is a poor fit if you need heavy daily volume, since the free tier caps daily queries, or if you work outside the browser, since it is not a native desktop or mobile app. Model choice is limited to GPT and Claude, with no other providers or local models.
Sources: this listing
What it does well
- Runs as a browser extension that overlays GPT and Claude in a sidebar on any webpage.
- Supports both OpenAI GPT and Anthropic Claude models from a single interface.
- Includes built-in chat history for reviewing previous conversations.
- Offered on a freemium pricing tier, allowing free use with paid upgrades.
Where it falls short
- The free tier limits the number of daily AI queries users can make.
- Functionality is limited to the web browser environment and is not available as a native desktop or mobile app.
- Model selection is restricted to GPT and Claude, with no support for other providers or local models.
Tagged
- Supports Claude
- Supports GPT
- Web-based
- Free
- Freemium
Compared with similar things
Picked by shared tags inside the AI Productivity.
- 01Freemium →OpenRouter
Unified API gateway for 200+ LLMs across providers with usage-based billing on a single account.
- 02Freemium →n8n
Open-source workflow automation with native LLM nodes — self-host on your own infrastructure.
- 03Freemium →LangSmith
Observability and evaluation for LLM apps — traces, datasets, A/B testing, and feedback collection.
- 04Freemium →Sider
ChatGPT + Claude sidebar for any browser tab — chat about the page, summarise, translate, draw.
- 05Freemium →ChatHub
Use GPT, Claude, Gemini, Bing, and more side-by-side in a single chat interface.
- 06Freemium →Make
Visual automation platform with AI modules for OpenAI, Anthropic, and self-hosted LLMs.
Related reading
- The Future of Marketing for People Who Build with AI
When AI makes building a product trivial and floods the web with generic content, marketing inverts: distribution becomes the moat, and distribution increasingly means being the source AI answer engines and buying agents cite and recommend. The durable move before 2027 is to engineer your product to be machine-discoverable and corroborated from day one — even at zero domain authority. Strong in the future means cited, not ranked.
Read guide → - How to Get Your First Users for a Vibe-Coded App
The cheapest way to get your first users for a vibe-coded app is organic short-video: post native-looking TikToks and Reels from accounts that read like your target user, and convert people in the comments — no ads, no influencers. It's slow at first and most clips flop, but it's how indie consumer apps go from zero to their first thousands of downloads.
Read guide → - How to Make Your App Go Viral with UGC
Going viral isn't luck — it's a format that earns watch time, run at volume. The founder of nomadtable grew it past a million downloads, solo, by ignoring view counts and chasing one number: how many people keep watching past the first three seconds. Here's that UGC playbook, with his real figures attributed throughout.
Read guide →
Featured on Vibedonalds
Own Merlin? Add this badge to your site to show you’re listed — and link back to your profile here.
<a href="https://vibedonalds.com/tools/merlin-extension" target="_blank" rel="noopener">
<img src="https://vibedonalds.com/badge/featured-on-vibedonalds.svg" alt="Merlin — Featured on Vibedonalds" width="240" height="60" loading="lazy" />
</a>Frequently asked questions
- What is Merlin?
- Merlin is a browser extension that puts GPT and Claude in the sidebar of any page, with built-in chat history.
- Is Merlin free?
- Merlin offers a free tier and paid plans with higher limits or premium features.
- What platforms does Merlin support?
- Merlin runs on web.
- What category does Merlin belong to?
- Merlin is in the AI Productivity category — AI-powered task trackers, calendars, note tools, and meeting assistants. Helps you do more with less context-switching.
- What are the downsides of Merlin?
- The free tier limits the number of daily AI queries users can make. Functionality is limited to the web browser environment and is not available as a native desktop or mobile app. Model selection is restricted to GPT and Claude, with no support for other providers or local models.