GPT-5.1 Update: All Changes Explained
The GPT-5.1 update made ChatGPT warmer, faster on simple tasks, more persistent on hard tasks, and easier to personalize. Here is what changed.
Ahmed Saad
Ahmed Saad is the content editor at ChatAI Guide. He reviews and updates the site's ChatGPT and OpenAI guides, checking them against OpenAI's official documentation, help center articles and release notes.
ChatGPT Plugins (Legacy): What Happened to Them
ChatGPT Plugins are legacy. Learn when they were retired, what replaced them, and how to migrate workflows to GPTs, Actions, Search, and Data Analysis.
Does ChatGPT Plus Include API Access?
ChatGPT Plus does not include OpenAI API access. Learn how Plus billing differs from API billing, how to get an API key, and when each option makes sense.
GPT-4.1 Review: Worth Upgrading?
Our GPT-4.1 review explains who should still use it, who should skip it, how it compares with GPT-4o and GPT-5, and whether the API cost makes sense.
ChatGPT Excel Prompts for Power Users
Copy-paste ChatGPT Excel prompts for formulas, cleanup, analysis, charts, dashboards, QA, Power Query planning, and safer spreadsheet workflows.
OpenAI API: Complete 2026 Beginner Guide
OpenAI API beginner guide for 2026 covering keys, Responses API, models, pricing, limits, tools, embeddings, audio, images, video, and production.
Code Interpreter Session Expired: How to Fix It
Fix the Code Interpreter session expired error in ChatGPT. Learn when to reload, reupload files, rerun analysis, start a new chat, or check OpenAI status.
ChatGPT Video Generator: Sora Inside ChatGPT
Learn how the ChatGPT video generator works through Sora, including access, plan limits, prompting workflow, safety rules, and when to use it.
Structured Outputs with the OpenAI API
Learn how OpenAI structured outputs work, when to use JSON schema, how they differ from JSON mode and function calling, and how to design schemas safely.
ChatGPT Customer Service: Build Your AI Helpdesk
Learn how to build a ChatGPT customer service helpdesk with routing, knowledge retrieval, human handoff, quality checks, and secure rollout steps.
Learn ChatGPT in 2026: Free Step-by-Step Course
Free beginner-friendly ChatGPT course for 2026. Learn setup, prompting, files, research, writing, data analysis, verification, and safe workflows.
OpenAI API Rate Limits: Tiers and How to Increase Them
Learn how OpenAI API rate limits work, what usage tiers mean, how to check your limits, and how to raise throughput without causing 429 errors.