It’s safe to say that we’ve not seen the true power and potential of IoT yet. The IoT market is set to almost double in value in the next five years – from $760 billion to $1386 in 2026. And this growth would not even be possible without APIs.
API stands for Application Programming Interface. It’s a set of lines of codes and specifications that allow two devices to communicate with one another. They serve as the interface between different programs. And, to put it bluntly, the whole concept of IoT falls down without APIs.
Moreover, the emergence of easy-to-code web API IoT – or Rest APIs – has made IoT more developer-friendly than ever before. Now, if you’re scratching your head and wondering “what is REST in IoT?” or have any other similar questions, we’re here to help.
Our guide to REST APIs in IoT explains what Rest IoT entails, the difference between REST and RESTful, the positives and negatives of REST, and much more. Let’s get into it.
What is REST API?
REST stands for Representational State Transfer. It’s an architectural style for developing web services. A lot of people believe that there is a REST protocol in IoT. However, REST itself is a concept, not an IoT protocol.
REST is the basis for the most widely used form of API and is designed to be used over any protocol. However, it typically uses HTTP or COAP to work with components in a particular IoT device, such as:
Web services are defined on the principles of REST and can be defined as a RESTful web service. RESTful web services can use normal POST, DELETE, PUT, and HTTP verbs of GET for working the components listed above.
What’s the Difference Between REST and RESTful?
A REST web service is a Representational State Transfer and an architectural pattern for creating web services.
On the other hand, the RESTful service is one that implements that pattern.
What’s better in IoT? MQTT or REST? Check out our guide here
Advantages of Using REST APIs
REST means that there’s a clear separation between client and server. As a result, products can be scaled up by a development team without much difficulty.
Familiarity and Usability
REST APIs use constructs that are familiar to anyone who has used HTTP – i.e. the internet. Unless you’re completely off the grid, you’ll have used the internet before.
On top of that, most IoT developers are already familiar with the REST architecture, such as SSL and TLS. This makes REST APIs the most easy-to-use API out there.
Developers can use any language that uses HTTP to make web-based requests. This is another reason why REST APIs are so popular with developers. They give you the power to program using a language you’re comfortable and familiar with to develop your IoT app.
Disadvantages of Using REST APIs
While the simple architecture of REST is a great entry point for budding IoT developers, those who want to do more or work with REST frequently may encounter limitations due to its architecture.
Lack of State
HTTP doesn’t store information between request and response cycles.
This can both be an advantage and a disadvantage. On the plus side, statelessness means every request and response is purposeful and understandable. This makes it very easy for you to decipher requests within the API’s code without context.
However, on the flip side, the majority of web applications require stateful mechanisms. And, as there is a clear separation between client and server, the burden of maintaining states falls firmly on your lap.
The more states that need to be programmed, the heavier and more difficult it becomes to maintain your device.
Lack of Security
REST doesn’t impose security, like SOAP APIs for example (more on that later).
The benefit of this is the REST is able to run on public URLs. However, it’s not good if you want to set up a confidential data passage between client and server.
REST vs. SOAP
REST APIs are heavily embedded and the favored API within IoT. However, if you’re not a fan, you do have other options.
REST is often compared to SOAP. However, even though they’re talked about in the same breath, there are actually a lot of fundamental differences between them.
Take a look at this comparison table and see how the two stand up alongside each other:
What is it?
An architectual style
REpresentional state transfer
Simple object access protocol
Can use the other?
Can use SOAP and any other protocol e.g. HTTP
It can't - because it's a protocol
RESTful inherits security from the transport layer
Defines its own security
Requires more bandwidth
Data Formats Compatible
Plain Text, HTML, XML, JSON etc.
The key benefit of using SOAP as an IoT protocol over REST, instead of HTTP, is if you’re looking for extremely secure and very formal communication.
Otherwise, it’s better the devil you know – stick with REST as your web-based IoT API.
The Bottom Line
So there you have it! You now know your REST from your RESTful and your architecture from the protocol.
While there are undoubtedly some limitations with REST as an API, we still believe it’s the best option for your IoT solution. It requires little bandwidth, is easy to scale up, and supports any programming language.
Without an API, IoT compatibility is not possible. So, in order to REST easy, choose REST as your IoT API.
Read Our Other Resources
We’ve published a range of IoT resources for our community, including:
- A Comparison of IoT Protocols, which provides a complete comparison of the major protocols and standards available.
- Buying versus building an IoT platform, which discusses how to choose the best option for you.
- Our guide on how to Develop IoT Apps and what platforms you can use.
- Find the right microcontroller by reading our Complete Guide to Microcontrollers for IoT.