Apollo (GraphQL) vs. Retrofit (REST): Which Data Fetching Tool Should You Use?

Choosing between GraphQL with Apollo and REST with Retrofit isn’t about picking a “winner” — it’s about matching the tool to your app’s needs. Let’s break down their strengths, weaknesses, and code-level differences like a pro.

1. Data Control: Ask for Exactly What You Need

Apollo (GraphQL):

• Fetch nested data in a single request:

query GetUserPosts($id: ID!) {  
  user(id: $id) {  
    name  
    posts {  # Nested data in one query  
      title  
      comments {  
        text  
      }  
    }  
  }  
}  

• No over-fetching: Get only name, posts, and comments — nothing extra.

Retrofit (REST):

• Often requires multiple endpoints:

interface UserApi {  
  @GET("/users/{id}")  
  suspend fun getUser(@Path("id") id: String): UserResponse  

  @GET("/users/{id}/posts")  
  suspend fun getPosts(@Path("id") id: String): List<Post>  
}  

• • Risk of over-fetching (e.g., receiving 20 user fields when you only need 2).

2. Performance & Network Calls

Apollo Wins When:

• Your UI needs diverse data (e.g., user profile + posts + comments).
• You want to minimize round trips (1 GraphQL call vs. 3 REST calls).

Retrofit Wins When:

• You need simple, cacheable requests (e.g., fetching a static product list).

3. Type Safety & Schema

Apollo (GraphQL):

• Auto-generate models from .graphql queries.
• Compile-time validation: Catch typos in field names before runtime.

Retrofit (REST):

• Manual model creation:

data class UserResponse(  
  val id: String,  
  val name: String,  
  // ... 20 other fields you might not need  
)  

• Runtime errors if the API response changes unexpectedly.

4. Caching & Offline Support

Apollo:

• Built-in normalized cache: Reuses data across queries (e.g., same User object in multiple screens).
• Optimistic UI updates: Pretend a mutation succeeded while it’s pending.

Retrofit:

• No built-in caching: Requires manual setup with OkHttp Interceptors or Room.
• Simpler for basic caching: Use @Headers("Cache-Control: max-age=3600").

5. Code Complexity

Apollo Setup:

• Define schemas, write queries, and generate code.
• More boilerplate upfront, but scales better for complex apps.

Retrofit Setup:

• Faster to start:

// Retrofit initialization  
val retrofit = Retrofit.Builder()  
    .baseUrl("https://api.example.com/")  
    .addConverterFactory(GsonConverterFactory.create())  
    .build()  

• Easier for simple APIs but can become messy with 50+ endpoints.

When to Use Which?

Pro Tips

• Hybrid Approach: Use Retrofit for file uploads and Apollo for data queries.
• Migrate Gradually: Add Apollo to one feature while keeping Retrofit elsewhere.

Your Turn:
Try replacing one REST endpoint with GraphQL this week.

Comment below: Which tool saved you more time (or headaches)?

#AndroidDev #GraphQL #Retrofit #Kotlin #APIs