Thread by @swapnakpanda

🪜 Introduction to GraphQL

"FAANG might have changed to MANGA, but GraphQL is still GraphQL" 😉

🧵 👇

1️⃣ What is GraphQL?

GraphQL is

→ a query language for your API (explained in 6️⃣)

→ a server-side runtime for executing queries using a type system you define for your data (explained in 7️⃣)

2️⃣ What is an API?

✪ API stands for "Application Programming Interface".

✪ You have an application. Your application has several data. Users of your application want to fetch those data. How would they be able to do that?

✪ One way is to provide them a GUI (Graphical User Interface). User can view the data and perform any action on the data using GUI.

✪ GUI has a shortcoming viz. "Extensibility". It means a user can consume the data only through that GUI. You cannot extend this functionality.

✪ The other option is to provide user the data programmatically. As a data owner, you facilitate your application's programming interface aka API.

✪ Using API, user can fetch and/or manipulate the data from any other application. So, it's "flexible" and "extensible".

3️⃣ How were we using APIs?

✪ In earlier days, API calls used to be made through web services using SOAP (Simple Object Access Protocol).

✪ Introduction of REST (REpresentational State Transfer) made the API development process faster. Consuming an API became easier.

4️⃣ REST API

✪ REST uses HTTP (no separate protocol)
✪ REST is stateless (because HTTP is stateless)
✪ REST defines the data to be consumed as a "Resource"
✪ REST uses HTTP verbs (GET, PUT, POST etc) to perform actions on the resources.

5️⃣ Shortcomings of REST

✪ Server defines the structure of a "Resource". Client has no take in it.

✪ When client wish to fetch "some" of that resource, it cannot. It has to consume it entirely.

✪ There is no way to define any relationship between resources. To fetch a related resource, you need to make another API call.

6️⃣ What is a Query Language?

To overcome these shortcomings of REST, a query language is developed.

✪ Using the query language, client decides "how much" to consume.

✪ Query Language allows to layout a schema.

✪ Using Schema, we define the resources and their relationships.

✪ Schema also defines various queries that can be made (aka end points).

✪ Client can fetch only what it requires without having to do several trips to server. Lower latency, less bandwidth. Happy Customer.

7️⃣ What is a Server-Side Runtime?

✪ The job of Server-Side runtime is to process the client query and provide only those details that's been requested for.

✪ Server-Side runtime use the schema for all validations.

8️⃣ What are different operations in GraphQL?

→ Query: To read data

→ Mutation: To write data

→ Subscription: To listen for a data

We will describe each in future threads.

9️⃣ Where can I learn more about GraphQL?

Check the 👇 link to learn GraphQL from official sources.

graphql.org/learn/

That's it for today's topic. I hope you enjoyed this introduction to GraphQL.

Reply me stating what more you wanna learn about GraphQL or anything. I will try to do the needful.

Till we see again, do take care. 👋