ChatGPT

ChatGPT launched on November 30, 2022, and became the fastest consumer software to reach 100 million users (in roughly two months). The product brought LLM-powered conversation to a general audience that previously had no easy access to frontier models. In 2026, ChatGPT has evolved far beyond a simple chatbot: it includes agentic tools like Operator for web tasks, Codex for coding agents, Deep Research for multi-step research synthesis, Canvas for collaborative writing and code, image generation via GPT Image, and spreadsheet assistance built into Excel and Google Sheets.

The model picker simplified significantly in 2026. Where 2025 had a confusing mix of GPT-4o, GPT-4.1, o1, o3, and o4-mini, the current interface has three primary tiers: Instant (fast everyday responses, default for all users including free), Thinking (deeper reasoning for hard tasks, paid tiers), and Pro (highest capability, Pro and Enterprise plans). GPT-5.5 Instant became the default model for all ChatGPT users in May 2026. Older models like GPT-4.5 and o3 are being retired from the consumer interface through mid-2026.

For builders, ChatGPT matters as both a product and a distribution channel. The free tier creates enormous reach for any AI product that integrates with ChatGPT's ecosystem. The API is separate from the ChatGPT product interface and gives developers direct programmatic access to OpenAI models. Custom GPTs (now called Skills in enterprise contexts) let teams build lightweight AI tools on top of ChatGPT without leaving the familiar interface.