# TestFlows Machine > TestFlows Machine is a deterministic execution machine in the cloud, provided as a self-serve service: you can sign up for free, and paid plans are available. It runs software built for Linux x86_64 and controls time, interrupts, random numbers and device input, so every run can be recorded, replayed exactly, and branched from any point to explore other outcomes. You use it from the `machine` command-line client or from the Python SDK. Install the client with `curl https://testflows.com/machine/install -fsS | bash`. It runs on Linux (x86_64 and arm64) and on Macs with Apple Silicon. Sign in with `machine login`, or set `TESTFLOWS_MACHINE_API_KEY` for scripts and agents. `machine --help` lists every command, and so does `--help` on each one. Each page below is one section of the Machine docs, in plain Markdown. In the Markdown files, `{% attention %}` starts a note. ## Start here - [Overview](https://testflows.com/docs/machine/overview.md): What Machine is, its concepts (disk, session, run, entry, checkpoint, branch, mark), and how to name a point in a run's history. - [Getting started](https://testflows.com/docs/machine/getting-started.md): Install the client, sign up and sign in, then go from a program to a branch in one first run. ## Guides - [Disks](https://testflows.com/docs/machine/disks.md): Build a disk from a binary, a Docker image or a Compose project, including on ARM machines, and manage disks. - [Sessions](https://testflows.com/docs/machine/sessions.md): Create, size, select and delete the cloud sessions your runs live in. - [Running a machine](https://testflows.com/docs/machine/running-a-machine.md): Create a run, drive it with `machine run`, wait for conditions, try different schedules, inspect it, and stop and start it. - [Checkpoints and branches](https://testflows.com/docs/machine/checkpoints-and-branches.md): Save checkpoints, branch with `fork`, `go`, `switch`, `rewind` and `detach`, see the tree, and mark branches. - [Replay](https://testflows.com/docs/machine/replay.md): Replay a recording, detect divergence, and compare or play back logs. - [Steering programs](https://testflows.com/docs/machine/steering-programs.md): Hold and release threads, focus on programs, write plan files, inject interrupts and change guest time. - [Reading the disk](https://testflows.com/docs/machine/reading-the-disk.md): Read files from a run's disk, at a checkpoint or an entry, without touching the run. - [Account and billing](https://testflows.com/docs/machine/account-and-billing.md): Manage the account, credits, plans, API keys and storage from the client. - [Scripting](https://testflows.com/docs/machine/scripting.md): JSON output, quiet mode, timeouts and exit codes for scripts and CI. ## Python SDK - [Python SDK](https://testflows.com/docs/machine/python-sdk.md): Install the SDK, sign in, and do from Python what the client does: sessions, runs, branches, replay, errors and example scripts. ## Optional - [Download the client](https://testflows.com/machine/download.md): Install the client, supported systems and how to check the download.