# Welcome to Quantum Cloud Services

Quantum Cloud Services (QCS) is Rigetti’s quantum-first cloud computing platform. With QCS, [our quantum processors (QPUs)](https://qcs.rigetti.com/qpus/) are tightly integrated with classical computing infrastructure and made available to you over the cloud.

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If you don't already have a QCS account, you can [request one](https://www.rigetti.com/get-quantum). See [how-to-use-rigetti-qpus](https://docs.rigetti.com/qcs/guides/how-to-use-rigetti-qpus "mention") for an overview of all the platforms on which Rigetti QPUs are available.
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## Quil SDK

The Quil SDK is a set of software tools that allows you to write quantum programs in [Quil](https://docs.rigetti.com/qcs/guides/quil/quil), then compile and run them on a simulator, or on a real Quantum Processor via QCS.

The SDK is comprised of the following:

* [**pyQuil**](https://docs.rigetti.com/qcs/references/pyquil): A Python library for building and executing Quil programs
* [**quilc**](https://docs.rigetti.com/qcs/references/quilc): An optimizing Quil compiler
* [**QVM**](https://docs.rigetti.com/qcs/references/qvm): A quantum virtual machine (quantum computer simulator)

When you're ready, continue on to learn how to start using QCS and the Forest SDK.