API Architectures¶
APIs connect applications, services, and data. Selecting the right architecture impacts scalability, performance, and maintainability. This guide covers common API styles, their strengths, and typical use cases.
Quick Comparison¶
| Architecture | Best For | Protocol | Data Format | Real-Time | Complexity |
|---|---|---|---|---|---|
| SOAP | Enterprise, legacy integration | HTTP, SMTP, FTP | XML | No | High |
| REST | Web, cloud, mobile | HTTP | JSON, XML | No | Low |
| GraphQL | Complex, flexible queries | HTTP | JSON | No | Medium |
| gRPC | Microservices, fast comms | HTTP/2 | Protobuf | No | Medium |
| WebSocket | Real-time, bidirectional | WS, WSS | Custom | Yes | Medium |
| Webhook | Event-driven, automation | HTTP | JSON, XML | Yes (push) | Low |
SOAP (Simple Object Access Protocol)¶
Protocol-independent, secure, and flexible. Used in enterprise applications for exchanging structured data between systems. Suitable for complex, secure, and transactional environments.
Example:
An online bookstore uses SOAP to connect with banks and warehouses.
RESTful (Representational State Transfer)¶
Stateless, scalable, and widely used for web and cloud applications. RESTful APIs use HTTP verbs and stateless requests.
Example:
A library system manages books with GET, POST, PUT, DELETE requests.
GraphQL¶
Clients request specific data in a single query, reducing over-fetching and round-trips. Useful for complex frontends.
Example:
A social app fetches user info, posts, and comments in one query.
gRPC (Google Remote Procedure Call)¶
Uses HTTP/2 and Protocol Buffers for fast, type-safe communication. Suitable for internal service-to-service calls in microservices architectures.
Example:
A gaming app updates scores in real time using gRPC.
WebSocket¶
Enables persistent, two-way communication for real-time applications. Keeps connections open for instant data flow.
Example:
A chat app delivers instant messages via WebSocket.
Webhook¶
Event-driven, push notifications between applications. Sends HTTP POSTs when events occur, automating workflows.
Example:
An e-commerce site notifies a tracking system when an order ships.