✍️ By Abhishek Kumar | #FirstCrazyDeveloper

🌐 Why This Matters

Modern businesses rely on APIs to connect systems, apps, and data.
Choosing between REST and GraphQL defines how efficiently your front-ends, mobile apps, and cloud systems communicate.

• REST is a proven workhorse — simple, cacheable, and easy to scale.
• GraphQL is the new precision tool — flexible queries, fewer round-trips, perfect for modern client-driven apps.

🧩 Understanding the Basics

💼 Why This Is Important for Business

APIs are no longer just technical interfaces — they are digital business enablers.
Every time your mobile app, website, or supply chain tool requests product data, pricing, or labels — it’s powered by APIs.

Choosing the right API model can directly impact time-to-market, infrastructure cost, and user satisfaction.

Example:
In a manufacturing ERP integration for AkzoNobel, a REST API delivering product information to multiple regional systems was returning ~1.2 MB of JSON per call.
Switching to GraphQL reduced payload size to 320 KB, saving 73% network bandwidth and improving response time by 45%.
When you have 100,000+ daily API calls, that translates to gigabytes saved and cost reduced on Azure bandwidth and API Management units.

🧠 How This Helps Developers and Architects

1. Developers Gain Speed and Clarity

• REST helps developers ship fast — each endpoint is explicit.
• GraphQL lets front-end developers query exactly what they need without backend changes.
• Reduced friction between UI and backend teams → fewer release dependencies.

2. Architects Achieve Scalability

• REST endpoints are independent — easier to deploy in microservices.
• GraphQL acts as an API orchestration layer, merging data from REST, SQL, Cosmos, and Azure OpenAI in one schema.

3. Improved Testing and Monitoring

• REST integrates easily with tools like Postman, Swagger, and APIM.
• GraphQL introspection and query analyzers offer deep visibility into consumer patterns.

4. Better Change Management

• With REST, versioning can break clients.
• GraphQL evolves schema without breaking clients — zero-downtime evolution.

⚙️ How It Improves the Business Process

📊 Real Data Snapshot

Net Result:
✅ ~43% faster page loads
✅ ~40% API cost reduction
✅ ~20% reduced release cycle time

🏢 Real-World Scenario (Manufacturing APIs)

Imagine AkzoNobel’s label printing portal needs product data for packaging:

• REST API: /api/products/123 returns all product fields — even ones unused by the client.
• GraphQL: Query only the required fields, reducing payload by 70% for faster dashboards.

💻 C# Implementation Examples

🔹 REST API with ASP.NET Core 10

[ApiController]
[Route("api/[controller]")]
public class ProductsController : ControllerBase
{
    private readonly IProductRepository _repo;

    public ProductsController(IProductRepository repo) => _repo = repo;

    [HttpGet("{id}")]
    public async Task<IActionResult> GetProduct(int id)
    {
        var product = await _repo.GetProductByIdAsync(id);
        if (product == null) return NotFound();
        return Ok(product);
    }
}

📦 Straightforward endpoint returning a resource.

🔹 GraphQL with HotChocolate in .NET 10

public class Query
{
    public Product GetProduct([Service] IProductRepository repo, int id)
        => repo.GetProductByIdAsync(id).Result;
}

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddGraphQLServer().AddQueryType<Query>();
builder.Services.AddSingleton<IProductRepository, ProductRepository>();

var app = builder.Build();
app.MapGraphQL(); 
app.Run();

🧠 Single endpoint /graphql where the client defines its own query.

🐍 Python Implementation Examples

🔹 REST API with FastAPI

from fastapi import FastAPI

app = FastAPI()

products = {"1": {"id": 1, "name": "Paint A", "price": 25}}

@app.get("/api/products/{product_id}")
def get_product(product_id: str):
    return products.get(product_id, {"error": "Not found"})

🔹 GraphQL API with Strawberry GraphQL

import strawberry
from fastapi import FastAPI
from strawberry.fastapi import GraphQLRouter

@strawberry.type
class Product:
    id: int
    name: str
    price: float

def get_product(id: int) -> Product:
    return Product(id=id, name="Paint A", price=25)

@strawberry.type
class Query:
    product: Product = strawberry.field(resolver=get_product)

schema = strawberry.Schema(query=Query)
app = FastAPI()
app.include_router(GraphQLRouter(schema), prefix="/graphql")

🧮 When to Choose Which

💬 Abhishek’s Take

REST is stable and predictable — your “API foundation.”
GraphQL is dynamic and client-friendly — your “API innovation.”
In real enterprise systems, hybrid APIs often win: REST for microservices, GraphQL for aggregations.

Businesses often underestimate how data shape affects user experience and cost.
When your data is large and structured, GraphQL helps you save time, money, and frustration — while REST remains your best friend for modular APIs.
The smart architect doesn’t choose one over another — they design hybrid APIs that scale.

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