ChatGPT Box is a free, open-source browser extension that weaves ChatGPT and other large language models deeply into everyday browsing. Available for Chrome, Edge, Firefox and Safari, it has earned about 10,800 stars on GitHub and remains actively maintained in 2026.
Once installed, the extension adds an AI answer box alongside search results on Google, Bing, DuckDuckGo and more, offers a floating toolbar whenever you select text — explain, translate, summarize, polish or answer in one click — and provides a persistent sidebar chat for longer conversations. It ships with site adapters that summarize YouTube videos, GitHub repositories, Reddit threads and articles, and supports both the ChatGPT web account and API mode with your own key, including access to models such as GPT, Claude and other providers through compatible endpoints. Everything is configurable: triggers, languages, custom prompts and keyboard shortcuts, and because it is open source there is no subscription and no account with the extension itself. The extension supports a long list of model providers beyond OpenAI, including Claude, Gemini, DeepSeek and self-hosted Ollama instances, so you are not locked to a single vendor. Power users can write custom prompts triggered from the toolbar, pin favorite conversations and export chat history for notes or documentation. It is translated into many languages and developed in the open, with new site adapters contributed by its community rather than a central team.
ChatGPT Box is completely free and open source under the MIT license. In API mode you only pay your model provider for usage.
ChatGPT Box is for heavy web users — researchers, students, writers and developers — who want AI assistance inside the pages they already read instead of a separate chat tab.