OpenAI can offer this compatibility because Microsoft’s file formats for Excel (.xlsx) and PowerPoint (.pptx) are open source, so OpenAI doesn’t need any permission to build tools that use them.

Microsoft has announced that it will start disabling external workbook links to blocked file types by default between October 2025 and July 2026.

OpenAI is reportedly developing ChatGPT to support .xlsx and .pptx file formats, expected to enable native editing and creation of Excel and PowerPoint documents.

External workbook links which point to file types blocked by Excel's Trust Center will be disabled by default starting in October 2025, as Microsoft tightens down on reducing the potential ...