If you're building or working with APIs, understanding these architectures is essential. In this blog, we’ll walk through the most common API architectures, how they differ, and when to use them.
What is API Architecture?
Before we jump into the types, let’s understand what API architecture means.
API architecture refers to the design style or rules and structure that an API follows to communicate with clients and servers. It defines how requests are made, how data is sent, and how responses are structured.
Now, let's explore the most common types of API architectures.
1. REST (Representational State Transfer)
REST is the most widely used API architecture today.
Key Features:
- Works over HTTP
- Uses standard HTTP methods like GET, POST, PUT, DELETE
- Relies on stateless communication (each call is independent)
- Returns data in JSON or XML format (usually JSON nowadays)
Pros:
- Simple and easy to use
- Scales well
- Works well with web browsers
When to Use:
- For public APIs (like Twitter, GitHub)
- When building standard CRUD (Create, Read, Update, Delete) services
Example:
http
CopyEdit
GET /users/123
Returns details of user with ID 123.
2. GraphQL
Developed by Facebook, GraphQL is an alternative to REST that allows clients to ask for exactly the data they need.
Key Features:
- Uses a single endpoint (/graphql)
- Clients define the structure of the response
- Reduces over-fetching and under-fetching of data
Pros:
- Flexible and efficient
- Ideal for frontend-heavy applications
- Great for mobile apps where bandwidth matters
When to Use:
- Complex apps with many different client needs
- When REST responses are too bulky or rigid
Example:
graphql
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{
user(id: "123") {
name
}
}
Returns only the name and email of the user, nothing more.
3. SOAP (Simple Object Access Protocol)
SOAP is a protocol rather than a design style like REST or GraphQL.
Key Features:
- Uses XML for request and response
- Has strict rules defined by WSDL (Web Services Description Language)
- Supports security and transactional messaging
Pros:
- Very reliable and secure
- Ideal for enterprise-level services (banking, insurance, etc.)
When to Use:
- In environments where strict contracts and security are a must
- Integration with legacy systems
Example:
xml
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<soap:Envelope>
<soap:Body>
<GetUser>
<UserID>123</UserID>
</GetUser>
</soap:Body>
</soap:Envelope>
4. gRPC (Google Remote Procedure Call)
gRPC is a high-performance API architecture developed by Google.
Key Features:
- Uses Protocol Buffers (Protobuf) instead of JSON or XML
- Works over HTTP/2
- Supports bi-directional streaming
Pros:
- Extremely fast and lightweight
- Great for microservices communication
- Supports multiple programming languages
When to Use:
- Internal service-to-service communication
- High-performance, low-latency systems
Example:
Instead of REST’s GET /users/123, a gRPC client might call:
protobuf
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rpc GetUser(GetUserRequest) returns (User) {}
5. WebSockets
WebSockets are not exactly an API architecture like REST or GraphQL, but they’re worth mentioning.
Key Features:
- Enables real-time, two-way communication
- Keeps the connection open (unlike REST which is request-response)
Pros:
- Ideal for live updates, chat apps, or real-time dashboards
- Low latency
When to Use:
- Real-time features: chat, multiplayer games, stock tickers
Quick Comparison Table
| Architecture | Data Format | Use Case | Pros |
| REST | JSON/XML | Web apps, CRUD APIs | Simple, stateless |
| GraphQL | JSON | Frontend-heavy apps | Flexible, efficient |
| SOAP | XML | Enterprise systems | Secure, standardized |
| gRPC | Protobuf | Microservices | Fast, multi-language |
| WebSockets | JSON/custom | Real-time apps | Bi-directional, live updates |
Final Thoughts
Choosing the right API architecture isn’t about picking the most popular one — it’s about selecting the one that fits your project’s needs.
- Want simplicity and wide adoption? Go with REST.
- Need flexibility and reduced payloads? Try GraphQL.
- Looking for performance and streaming? Use gRPC.
- Working with older, enterprise systems? Stick with SOAP.
- Building real-time apps? WebSockets is your friend.
Each architecture has its strengths and trade-offs. Understanding them will help you make smarter decisions and build better APIs.
Read more on - https://keploy.io/blog/community/types-of-apis-and-api-architecture