OpenAI ChatGPT 5.5 is the newest flagship (GPT-5.5) with a 1,050,000-token context window and up to 128,000 tokens of output. Better reasoning, creative writing, coding, and multimodal understanding than 5.4. Best for very long documents, large codebases, and long-form generation. For everyday tasks, 5.4 mini or nano is cheaper. If you need to search the web for information, please turn on the "Web Search" switch. Maximum context window (input and output combined): about 1,050,000 tokens. Maximum total input per request (including history): 922,000 tokens. Maximum output per reply: about 128,000 tokens (model reasoning, if any, counts toward this limit). Maximum total upload size per request: 256MB (all files and message content combined). Accepted document formats: pdf, docx, xlsx, pptx, txt, csv (file content is provided to the model as extracted text). Accepted image formats: gif, jpeg, jpg, png, webp. Maximum number of images: 1500. Maximum size per image: 50MB. Maximum total image size per message: 384MB (text and history share the same request size limit; uploads close to the limit may still be rejected). Image dimensions: 200 to 8,000 pixels per side. Maximum image resolution: 36,000,000 pixels in total. Output content formats: Text/Image This module supports continuous conversations. AI can make mistakes. Please verify important information.