ChatGPT

Getting Started

1. Visit chatgpt.com and sign up for a free account — you get GPT-4.1 mini access immediately.
2. Upgrade to ChatGPT Plus ($20/mo) for GPT-4.1, o3, o4-mini, DALL-E, and higher usage limits.
3. For Codex and the full model lineup, upgrade to ChatGPT Pro ($200/mo).
4. For API access, go to platform.openai.com to get your API key.

Model Lineup

• GPT-4.1 — The latest fast multimodal model. Strong at coding, instruction following, and long-context tasks. Available in standard, mini, and nano variants.
• o3 — OpenAI’s most powerful reasoning model. Uses extended “thinking” for complex math, science, coding, and multi-step problems.
• o4-mini — Fast, efficient reasoning model. Great balance of intelligence and speed for everyday tasks.
• Codex (codex-1) — OpenAI’s autonomous coding agent. Runs in a cloud sandbox, reads your full repo, writes and edits code, runs tests, and creates PRs on GitHub. Works asynchronously — assign tasks and come back to finished work. Based on o3, fine-tuned with RLHF for software engineering.
• GPT-4o — Previous generation multimodal model, still widely used and available.

Key Features

• Codex coding agent — Connect your GitHub repo and assign coding tasks in natural language. Codex clones your codebase into a sandboxed environment, writes code, runs your test suite, iterates on failures, and opens a PR when done. Multiple tasks run in parallel.
• Deep reasoning with o3 — Extended thinking mode that works through complex problems step-by-step before responding, dramatically improving accuracy on hard tasks.
• Multimodal I/O — Text, images, audio, video, and file uploads in a unified chat interface. Generate images with DALL-E 3 inline.
• Real-time web search — Searches the internet for current information, news, prices, and events when needed.
• Code Interpreter — Executes Python in a sandboxed environment for data analysis, charting, file conversion, and computation.
• Canvas — A side-by-side editing workspace for writing and code, where you can collaborate with ChatGPT on documents and programs.
• Custom GPTs — Create and share tailored AI assistants with specific instructions, knowledge files, and API actions. Browse the GPT Store for community-built specialists.
• Memory — Remembers your preferences, projects, and context across conversations for more personalized responses.
• Voice mode — Real-time spoken conversations with natural-sounding voice synthesis and understanding.
• Operator and deep research — Agentic features that browse the web, perform multi-step research, and complete tasks autonomously.