Comparison of API Technologies

Information GraphQL .NET Core gPRC REST

1. REST

Representational State Transfer

Pros

1.1 Simplicity and Familiarity

Ubiquitous in web development.
Easy to understand, widely adopted in .NET using controllers.

1.2 Rich Ecosystem

Supported natively in ASP.NET Core.
Integration with Swagger/OpenAPI for documentation.

1.3 HTTP-Based

Works well with standard infrastructure (browsers, proxies, firewalls).

1.4 Stateless

Makes scaling easier.

Cons

1.1 Over-fetching/Under-fetching

Clients may receive too much or too little data, requiring additional logic to handle data shaping.

1.2 Multiple Round Trips

Aggregated views often require several endpoint calls, increasing latency and overhead.

1.3 Rigid Resource Mapping

Changes in client needs often require modifying the server structure or adding new endpoints.

1.4 Verbosity

Deeply nested objects or complex resource relationships are hard to express concisely

2. GraphQL

query language/runtime that allows clients to define the structure of the response

Pros

2.1 Precise Data Fetching

Clients request only the data they need, reducing over-fetching and payload size.

2.2 Single Endpoint Simplicity

One endpoint simplifies routing and API surface management.

2.3 Strongly Typed Schema

Self-documenting through introspection and type system; tooling like GraphQL Playground improves development experience.

2.4 Efficient Aggregation

Nested queries allow the client to retrieve related data in a single request, reducing round-trips.

Cons

2.1 Complexity for Simple Use Cases

Introduces additional abstraction that may not be needed for basic CRUD operations.

2.2 Limited Built-In Caching

Lacks native HTTP caching mechanisms; requires client-side or server-side caching strategies.

2.3 Security Considerations

Must guard against overly complex queries, recursion, and query depth abuse.

2.4 Steep Learning Curve

Requires understanding of schemas, resolvers, and query execution models, especially for advanced features like federation.

3. gPRC

Google Remote Procedure Calls

Pros

3.1 High Performance

Binary Protobuf serialization and HTTP/2 enable faster data transmission and lower resource usage.

3.2 Contract-First and Strong Typing

Service definitions in .proto files ensure strict interfaces across services and languages.

3.3 Advanced Communication Patterns

Supports streaming (client, server, and bi-directional) for real-time and long-lived connections.

3.4 Excellent for Internal Microservices

Lightweight, fast, and language-neutral, making it ideal for backend service-to-service communication.

Cons

3.1 Limited Browser Support

Native gRPC is not supported in browsers; requires gRPC-Web or fallback to REST/JSON for web clients.

3.2 Debugging Difficulty

Binary protocol is not human-readable, making manual inspection harder without specialized tools.

3.3 Steep Tooling Setup

Requires compiling .proto files and configuring build pipelines, which adds development complexity.

3.4 Weak Native Caching

Lacks built-in mechanisms for standard HTTP caching, making client-side performance optimization more manual.

4. Feature Comparison Table

Feature	REST	GraphQL	gRPC
Protocol	HTTP/1.1	HTTP/1.1 / HTTP/2	HTTP/2
Message Format	JSON	JSON	Protocol Buffers (binary)
Tooling in .NET	Built-in ASP.NET Core	HotChocolate, GraphQL.NET	Grpc.AspNetCore
Client Control Over Data	Low	High	Medium (contract-based)
Streaming Support	No	No	Yes
Performance	Moderate	Moderate	High
Caching	Strong (HTTP caching)	Weak	Weak
Browser Support	Excellent	Excellent	Requires gRPC-Web

5. When to Use What

REST	GraphQL	gRPC
Public Web APIs	Complex data querying for frontend	High-performance backend systems
Develop ease and quick prototyping	Multiple nested/related entities	Internal microservices
Strong HTTP caching and browser compatibility	Client-controlled data fetching with minimal over-fetching	Bi-directional streaming or real-time communication
Simple, resource-oriented CRUD operations	Single endpoint with dynamic queries	Contract-first APIs with strong typing

6. Real-World C# Consideration

API	Tooling & Dev Experience	Testing & Debugging	Versioning Approach
REST	Native support in ASP.NET Core; OpenAPI document generation* , seamless Visual Studio integration.	Easy to test using Postman, curl, or OpenAPI; HTTP traffic is human-readable.	Commonly uses URI versioning or custom headers; supported by ASP.NET routing.
GraphQL	Libraries like HotChocolate provide rich schema-based development; introspection and auto-generated docs help with client integration.	Requires tools like GraphQL Playground or Banana Cake Pop; more complex due to resolver chains and dynamic query shapes.	Challenging; relies on schema evolution and deprecation rather than endpoint changes.
gRPC	Requires .proto files and code generation via Grpc.Tools; tightly integrated into .NET SDK with support in Visual Studio.	Binary messages make debugging harder; requires tools like grpcurl or custom logging for inspection.	Built-in support for evolving schemas using optional fields and reserved keywords in proto files.

* Microsoft has dropped support of Swagger starting with .NET9 therefore we only meantion OpenAPI here..

7. Conclusion

API	Summary
REST	Best suited for standard CRUD operations, public APIs, and quick development cycles. Strong tooling in .NET and widespread industry support make it a safe default.
GraphQL	Great for client-heavy applications that require dynamic and precise data fetching. Ideal when you want frontend teams to shape responses or aggregate nested data.
gRPC	Best fit for high-performance, internal communication between microservices or systems where bandwidth and speed matter. Less ideal for browser-facing APIs.