What Is the Internet of Things?

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Updated October 29, 2026

The Internet of Things (IoT) is a global infrastructure for the information society. It enables advanced services by interconnecting things, both physical and virtual, using existing and evolving interoperable information and communication technologies. This is the definition given in an ITU-T Recommendation.

Contents

An illustration of a thing joined through a network to a place where data is viewed.

An example of a smart object
A link
A screen for viewing data

What you will learn

Say what IoT is in your own words.
Explain why people connect things to a network.
Spot where the term IoT came from and why small devices have limits.

Before you start

No prior knowledge needed. Knowing how to use a phone or a computer is enough.

What is a "thing" in IoT?

IoT includes physical and virtual things interconnected through interoperable information and communication technologies. An IETF document describes smart objects as computing devices that can understand and react to their surroundings; this describes smart objects, not a requirement that every IoT thing be a sensor, actuator or computer.

RFC 8576 also calls the computing devices it describes smart objects or smart devices.

For example, building-automation devices, cellular phones and machine-to-machine (M2M) devices all benefit from interacting with other things nearby or somewhere on the Internet.

An example of a smart object that can take in information, react and communicate with another thing.

The surroundings
An example of a smart object
Exchange in both directions
Another thing

Why do people connect things to a network?

People connect things to a network to process, view and gain insight from the data the things collect. A growing number of products put the Internet Protocol Suite on smaller and smaller devices to do this.

When data from many different devices is combined, the network effect can increase.

Data from many devices is gathered to be viewed together.

Many different devices
Where data is gathered
Results to view

Where did the term IoT come from?

The term IoT was first coined in 1999 by the Auto-ID center. The center envisioned a world where every physical object has a radio-frequency identification (RFID) tag with a globally unique identifier.

Since then, the meaning of IoT has expanded. It now encompasses a wide variety of technologies, objects and protocols.

From one idea about identification tags, IoT grew to cover many kinds of things.

A radio identification tag
A thing
A different kind of thing

What limits do small IoT devices have?

Small devices often run with few resources. Some constrained devices may work under severe limits, such as limited battery and computing power and little memory.

So when you think of IoT, do not picture every thing as powerful as a phone.

A comparison of two small items with a larger block.

A nearly empty battery
Small memory
A larger server

Real-world example

Try this with an adult. Look around your home and choose three items that can connect to a network or to other items, such as a phone. For each one, ask whether it sends or receives information. If it does, where does it get that information, and does it react to it?

Common misunderstandings

IoT is only smart home gadgets. According to an IETF document, the meaning of IoT has expanded and now encompasses a wide variety of technologies, objects and protocols.

Every IoT device is as powerful as a phone. Another IETF document says constrained devices may have limited battery and computing power and little memory.

IoT is a very new term. According to an IETF document, the term was first coined in 1999.

IoT interconnects physical and virtual things through interoperable information and communication technologies; some smart objects are computing devices that sense or react to their surroundings.
People connect things to process and view data, and combining data from many devices can increase the network effect.
The term IoT was coined in 1999 and now covers much more, while small devices may have limited battery, computing power and memory.

Terms in this article

English and Vietnamese terms, with the meanings used here. Hover, tap or Tab to a term with a dotted underline for an explanation as you read.

Internet of ThingsInternet vạn vật: Infrastructure that interconnects physical and virtual things through interoperable information and communication technologies to enable advanced services.
Smart objectVật thông minh: A computing device that can receive information from its surroundings and respond.
Constrained deviceThiết bị bị ràng buộc: A device with tight limits on battery power, processing or memory.
RFID tagThẻ nhận dạng bằng sóng vô tuyến: A tag identifying an object by radio; the early IoT vision gave each object its own identifier.
Network effectHiệu ứng mạng: An effect of a network that can increase when data from many devices is combined.

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