# Cloud computing

> Renting computers over the internet instead of buying your own.

- Level: Basic
- Topics: Cloud
- URL: https://tidbit.legios.com.ar/cloud-computing/
- In Spanish: [Computación en la nube](https://tidbit.legios.com.ar/es/cloud-computing/)

**Cloud computing** means using someone else's computers over the internet, paid by the hour or by use, instead of buying and running your own. The "cloud" is not in the sky: it is huge buildings full of servers (a data center) owned by companies like AWS, Microsoft and Google, which rent out slices of them.

What you rent ranges from a bare virtual machine (Amazon EC2), to file storage (Amazon S3), to a managed database, to a function that runs for a few milliseconds (AWS Lambda). You click a button or call an API, and the machine exists a minute later; delete it and the bill stops.

Why it matters: a startup can begin with one small server and grow to thousands without ever buying hardware. Netflix, your bank's app and most AI chatbots run in the cloud. The trade-off is that you depend on the provider, and the bill grows with use, so a mistake left running over a weekend can get expensive.

## An analogy

Electricity from the grid. You do not build a power plant in your backyard; you plug in, use what you need, and pay the meter at the end of the month.

## Keep in mind

- The three biggest providers are AWS, Microsoft Azure and Google Cloud.
- You pay for what you use: per hour, per gigabyte or per request.
- "Public cloud" means shared data centers; "on-premises" means servers you own.
- Elasticity, adding or removing capacity in minutes, is the whole point.

## Go deeper

- [What is cloud computing? (AWS)](https://aws.amazon.com/what-is-cloud-computing/)
- [Cloud computing (Wikipedia)](https://en.wikipedia.org/wiki/Cloud_computing)

## Related terms

- [Internet](https://tidbit.legios.com.ar/internet/): A worldwide network of networks that lets any connected device reach any other.
- [Server](https://tidbit.legios.com.ar/server/): A computer whose job is to answer requests from other computers, all day, every day.
- [Data center](https://tidbit.legios.com.ar/data-center/): A building full of servers where the internet, the cloud and AI actually run.
- [Microsoft](https://tidbit.legios.com.ar/microsoft/): The company of Windows and Office, now just as much a cloud company with Azure.
- [Google](https://tidbit.legios.com.ar/google/): The search company that gives most products away and makes its money on ads.
- [Virtual machine](https://tidbit.legios.com.ar/virtual-machine/): A complete computer made of software, running inside a real one.
- [Amazon EC2](https://tidbit.legios.com.ar/amazon-ec2/): Virtual computers you rent by the hour, in any size, and switch off when done.
- [Amazon S3](https://tidbit.legios.com.ar/amazon-s3/): A giant online drawer for files, rented by the gigabyte.