When to use REST, GraphQL and gRPC?

RESTvsGraphQLvsGRPC.md

REST (Representational State Transfer)

REST is a standard for designing networked applications. It uses HTTP methods to implement the concept of CRUD (Create, Read, Update, Delete).

When to use REST:

1. Public APIs for third-party developers : REST is widely adopted and understood by many developers, making it a good choice for public APIs.
2. Microservices with HTTP/JSON : If your microservices are lightweight and primarily use HTTP/JSON, REST can be a good choice.
3. Stateless operations : REST is stateless, meaning each HTTP request happens in complete isolation. When the client makes an HTTP request, it includes all information necessary for the server to fulfill that request.
4. Cacheable data : If your application serves data that can be cached to improve performance, REST can be a good choice because HTTP supports caching out of the box.
5. Web applications : REST is a good fit for web applications, especially when combined with JavaScript frameworks like Angular or React.
6. Mobile applications : REST APIs are commonly used in mobile applications due to their simplicity and the widespread support in many programming languages.
7. Integration with third-party services : Many third-party services support RESTful APIs, making integration easier.
8. Prototyping : REST is simple to understand and use, making it a good choice for prototyping and early development.
9. When simplicity and speed of development are key : REST is straightforward and easy to use, which can speed up development.
10. When the client and server are highly decoupled : REST allows for a high degree of separation between the client and the server.

GraphQL

GraphQL is a query language for APIs and a runtime for executing those queries with your existing data. It provides an efficient and powerful alternative to REST.

When to use GraphQL:

1. When you need to fetch complex data with a single API call : GraphQL allows the client to specify exactly what data it needs, which can reduce the amount of data that needs to be transferred over the network and improve performance.
2. When you have rapidly changing data requirements : With GraphQL, the server defines the capabilities and the client chooses what it needs at runtime. This can make it easier to evolve your API over time.
3. When you need real-time data : GraphQL has built-in support for real-time data with subscriptions.
4. When you need to aggregate data from multiple sources : GraphQL can aggregate data from multiple sources with a single query.
5. When you need to reduce over-fetching and under-fetching : With GraphQL, clients can specify exactly what data they need, which can help to eliminate over-fetching and under-fetching problems.
6. When you need to version your API : GraphQL eliminates the need for versioning your API because you can add new fields to your GraphQL API without impacting existing queries.
7. When you need to build a complex UI : GraphQL can be a good choice for complex UIs because it allows the client to fetch exactly what it needs.
8. When you need to reduce the number of API calls : With GraphQL, you can often replace multiple REST API calls with a single GraphQL query.
9. When you need to build a self-documenting API : GraphQL APIs are self-documenting, making it easier for developers to understand what data is available.
10. When you need to build a type-safe API : GraphQL schemas are strongly typed, which can help to catch errors at compile time rather than at runtime.

gRPC (Google Remote Procedure Call)

gRPC is a high-performance, open-source universal RPC framework. It uses Protobuf by default for communication, which is a very efficient mechanism compared to JSON used in REST and GraphQL.

When to use gRPC:

1. When you need to build a high-performance system : gRPC is designed for high-performance systems and can handle a large number of requests per second.
2. When you need to stream data : gRPC supports streaming data in both directions, which can be useful for real-time applications.
3. When you need to build a microservices architecture : gRPC is a good choice for microservices because it allows you to define services in a .proto file and generates server and client code.
4. When you need to build a distributed system : gRPC supports various features like load balancing, tracing, health checking, and authentication, which are essential for distributed systems.
5. When you need to build a system with low latency : gRPC uses HTTP/2, which is a binary protocol and more efficient than HTTP/1.1 used by REST.
6. When you need to build a system with strong API contract : gRPC uses Protobuf, which enforces a strong contract between the client and the server.
7. When you need to build a system with multiple programming languages : gRPC supports multiple programming languages, making it a good choice for a system that uses multiple programming languages.
8. When you need to build a system with bi-directional communication : gRPC supports bi-directional streaming, which can be useful for real-time applications.
9. When you need to build a system with flow control : gRPC has built-in flow control features, which can help to improve the performance of your system.
10. When you need to build a system with error handling : gRPC has built-in error handling features, which can help to improve the reliability of your system.