OpenAI is adding support for plugins. They allow integration into ChatGPT with real-time information, external knowledge (such as personal notes or company knowledge), and perform actions (like booking a flight, ordering food, etc.)
Companies that have already created plugins include: Expedia, FiscalNote, Instacart, KAYAK, Klarna, Milo, OpenTable, Shopify, Slack, Speak, Wolfram, and Zapier.
Currently, it's only available via whitelist.
Website: https://openai.com/blog/chatgpt-plugins
Documentation: https://platform.openai.com/docs/plugins/introduction
Github (example): https://github.com/openai/chatgpt-retrieval-plugin