Understanding Real Time APIs- Types & Use Cases

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The day when I felt proud of being one among millions of developers who are working tirelessly to scale up the real-time APIs.

Confused? Hold on, let me explain.

While I was surfing memes over social media and scrolling about the people uploading content about their lifestyle and emotions, I was just wondering about the technology that is powering these millions of content at a single point in time. This time I was not only thinking about Feeds but also about the food delivery apps, cab booking apps, eCommerce sites, and WhatsApp/Messenger chat applications, these all apps give us amazing real-time experiences.

And Guess what all these applications have only one backbone that is scalable real-time APIs. Let us dig further into Real-time APIs.  

Table of Content

  1. What is Real-time?
  2. Why are Real-time APIs required?
  3. Type of Real-time APIs?
    A. client-Driven and server-driven
    B. Polling.
    C. Long polling.
    D. Webhooks.
  4. Daily use cases of real-time APIs?
  5. Conclusion

What is Real-time?

Any information that is fed within 30ms is considered real-time. Let us look at the scientific ways why 30ms? 

  1. Science has discovered that human is capable to capture or scan an entire image within 10ms (study by neuroscientists at MIT)  
  2. To synchronize video it takes 6 to 20ms, i.e. the synchronization between the image and sound in the video.
  3. It takes less than 30ms to send out the data wirelessly and now with the introduction of 5G technology, it is now possible to get the wireless speed of 1 Gbps. 

Real-time is just like connecting anything on the planet which has a proper set of integrations and the experience should feel like face-to-face communication between two or more people.

With the rise of technology, real-time communications are getting more and more advanced with the use of APIs. APIs are acting as a perfect high-speed network cable between clients and owners. 

 Why are Real-time APIs required?

Real-time APIs are required to serve high-level interactive experiences. Considering the apps that we discussed in the introduction earlier, they  are highly reliable on real-time APIs and their connectivity to the servers. 

Like the food delivery service uses an API to connect between restaurants and the food delivery guys, Uber/ Ola or any cab service company uses Google Maps APIs to locate and figure the distance between source and destination.

Every individual wants to get things done in no time so  this real-time experience comes into the picture and it highly relies on API connectivity. It is considered that infrastructure for real-time APIs should not take more than 30ms to process a single API request and sometimes it gets as low as 3-6ms! This sounds a bit complex but not impossible. 

Types of Real-time APIs?

When we talk about APIs the word integrations pops up automatically because whenever an API is used, it connects two or more devices to process the desired task [which is integrated within the devices]. Integration makes our task much simpler like once you are integrating an API that will command application A to do some tasks and pass on the response to application B where the task at B is automatically executed.

These integrations are divided into two parts: client-driven and server-driven. Client-driven integration is simpler compared with server-driven where a person interacts with the client and waits for the response from the server and server-driven applications are quite different where changes are made to servers and clients need to be aware of those changes.

Client-Driven Integration

To understand in-depth, let us assume that we want to order a meal from Mc’d where the APIs are on the server end and our smartphone app is a client. A person uses an application to select his favorite meal and hits the order and pay button. Now as soon as the person interacts with the order button the client [smartphone app] knows that an API request has to be made to the Mc’d server. 

In general, the client knows when to act on the customer’s action and how. So as soon as there are some changes to the data on the client-side an API request is made to the server with no extra time (hence it’s real-time) and efficient. 

Server-Driven Integration

Assuming the above example, once the order is placed, now customers might want to know when their meal is ready and when it will be delivered. How can we use the APIs to provide them updates? Because the customer has nothing to do with making the meal. Here the server has to keep the customer updated with the order status. If this can’t be done then probably we are stuck!!

There are a couple of solutions software engineers used to update the client when servers respond. Let’s take a look at each.


When the request has to be made by the client only, then the easiest solution to keep the client up-to-date is to keep asking repeatedly for updates for the same resource as shown in the figure below. This technique is called Polling.

Let’s hop on our Mc’d meal order, polling for the status of our meal order might look like the following.

In the above approach, real-time communication is achieved by making frequent requests (polls). A large number of requests will move you closer to the real-time status update. Just like running a script to update a MySQL table and checking the same table update count on the terminal. If the poll is not frequent then it may not be aware of the latest updates on the server which communicates wrong information to the client. So it is recommended to poll every minute to keep the client and server in sync.

Long Polling (or Polling with patience)

Long polling comes into the picture when the requests are limited- if the API requests are free no one will worry about the efficiency and the preference would be always Polling. Since every request made over the internet requires cost, handling such a huge amount of API requests gets costlier with server and data usage. 

Long Polling was built to make these requests cost-efficient and can act as an optimized way of sending APIs over the network. Long Polling concept is the same as Polling, where the client asks repeatedly for updates from the server but the only difference here is the server doesn’t respond immediately. It makes clients wait until there are some changes on the server.   

Let’s revisit the polling example from above, but this time with a server that uses the long polling trick.

Long Polling technique is quite simple and smart where it makes sure that the client makes the initial request but also considers that client won’t get the server’s response immediately. So both client and server agree to keep the connection open unless there is a final response from the server.  


Webhooks are HTTP POST callback URLs that are developed to receive a response whenever an event occurs. They act as a lightweight data-sharing mechanism and are simple, effective to run on the server as they don’t require keeping the connection open which was a drawback for the long polling technique.

To get more details about the webhook let’s assume an example of our Mc’d Meal. So when a client orders a meal it completes the request and waits for an update. Using webhook the client doesn’t need to send requests frequently for updates, instead an URL will be configured at the client’s end so whenever the next update (event) is ready from the server it will be pushed automatically to the server. 

Daily use cases of real-time APIs

When it comes to real-time, the experience means a lot no matter what you are into.  It can be refreshing feeds, sending WhatsApp chat, uploading a cool picture on Instagram, nowadays everything around technology is built around real-time. Let’s check out a few daily life examples of real-time.

Real-time Chat APIs

One of the crucial factors that affect customer satisfaction is Low latency. Without low latency, the customer experience within your chat apps is dropped which impacts revenue and decreases the reputation among other competitors. 

Fraud Detection 

Considering financial sectors, every transaction is vital when data is processed. So when an offer for credit cards or coupons is made this sector employs fraud detection for the customer and makes sure the data is safe and under security at the point of sale. One can imagine if this Fraud detection is not real-time then the amount of fraud/loss of finance for an individual.


Without APIs, it becomes impossible for IoT devices to process and deliver the responses at incredible speed. Devices like home automation, medical device monitoring, smart lock, Air quality monitor, and many such devices. IoT devices are one of the  fast-growing gadgets which leverage the power of real-time APIs.


In this blog, we learned about what is a real-time API and how it helps us to improve customer experience by changing the speed of normal API to super-fast API. 

We also saw  why these real-time APIs are required and how the level of integration has changed due to that. If you have any thoughts or queries about the types of API that are used by developers to build high-quality real-time chat experience and improve the overall flow of developing amazing IoT devices, please share with us in comments. We’d love to receive your comments and do our best to explore this topic more with you.