Voices
Simon Willison Ships 'CORS Chat' — a Browser-Only Client for Any CORS-Enabled OpenAI Responses Endpoint, Built to Compare Qwen 3.8 27B on an M5 MacBook vs an NVIDIA DGX Spark
On August 15, 2026, Willison published CORS Chat, a client-side web UI that talks directly to any OpenAI Responses-compatible endpoint that sends CORS headers — no server, with conversations persisted in the browser and exportable as JSON. He built it specifically to run the same prompts against Qwen 3.8 27B served by LM Studio (using its --cors flag) on an M5 MacBook Pro and on an NVIDIA DGX Spark, and also tested it against OpenRouter. Two details are worth stealing: per-endpoint custom headers, and progressive SVG rendering that draws the image while tokens are still streaming. He notes the tool was written with GPT-5.6-Sol at xhigh.
↳ Follow the thread