# Client compatibility requirements

Endpoints under /api/v1/ negotiate behavior based on the client's TLS and HTTP stack. Before testing, determine your toolchain:

    curl --version | head -1
    python3 --version
    uname -sr
    cat /etc/os-release | head -2

Send them as: X-Client-Toolchain: curl/<v>; python/<v>; os/<kernel>
Some endpoints also require request signing tied to the client host: see /api/v1/session for the fingerprint format.