Try this
llama-server on Vulkan — the first /v1
llama.cpp’s llama-server README documents OpenAI-compatible GET /v1/models, POST /v1/chat/completions, and POST /v1/responses. House daily-driver flags from the 35B recipe: ./build-vk/bin/llama-server -m ~/models/Qwen3.6-35B-A3B-UD-Q5_K_XL.gguf -ngl 99 -c 262144 --cache-type-k f16 --cache-type-v f16 --host 127.0.0.1 --port 8080. Vulkan first; HIP / ROCm is the alternative compile on /rocm/vulkan-hip. Upstream default --port is 9931 in the current README — we pin --port 8080 so harnesses on this site keep http://127.0.0.1:8080/v1. Confirm with curl -s http://127.0.0.1:8080/v1/models. Those flags and the 35B decode table are measured on llama.cpp on the local desktop.