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Serialization & Deserialization (Client–Server Communication)

What Problem Are We Solving?​

  • Client (e.g., JavaScript frontend) and server (e.g., Rust backend) use:

    • Different programming languages
    • Different data types

  • Question:

    • How do they understand each other’s data?

Core Idea: Common Format​

  • Solution:

    • Define a standard format both client and server agree on

  • Process:

    • Client converts its data → standard format
    • Server converts standard format → its own data structures

  • This process is called:

    • Serialization (to standard)
    • Deserialization (from standard)

Definition​

Serialization​

  • Converting data → common transferable format

  • Example:

    • JavaScript object → JSON

Deserialization​

  • Converting data from common format → language-specific structure

  • Example:

    • JSON → Rust struct / Python dict

Simple Flow​

  1. Client creates data (JS object)
  2. Serializes → JSON
  3. Sends via HTTP
  4. Server receives JSON
  5. Deserializes → native object
  6. Processes logic
  7. Sends response (JSON again)
  8. Client deserializes and renders UI

Why Do We Need It?​

  • Language-agnostic communication
  • Cross-platform compatibility
  • Standardized data exchange

Where It Happens in Network Stack​

  • Happens at Application Layer

  • Lower layers:

    • Convert data into:

      • Packets
      • Bits (0/1)

  • Important:

    • Backend engineers mostly care about:

      • JSON level
      • Not underlying network encoding

Common Serialization Formats​

1. Text-Based Formats​

  • Human-readable
  • Used in ~80% of web APIs
  • Lightweight
  • Easy to parse

Others​

  • XML
  • YAML

2. Binary Formats​

  • Compact & faster
  • Not human-readable

Example​

  • Protobuf (Protocol Buffers)

JSON (Focus Format)​

What is JSON?​

  • Stands for:

    • JavaScript Object Notation

  • Language-independent

  • Looks like JS object

JSON Structure Rules​

  • Starts with {} (object)

  • Keys:

    • Must be strings
    • Must be in double quotes

  • Values can be:

    • String
    • Number
    • Boolean
    • Array
    • Nested object

Example JSON​

{
  "name": "Alice",
  "age": 25,
  "isStudent": false,
  "address": {
    "country": "India"
  }
}

Key Properties of JSON​

  • Human-readable
  • Lightweight
  • Easy to debug
  • Widely supported

Real API Example​

Request (Client → Server)​

{
  "id": 1,
  "title": "Book",
  "author": "John"
}
  • Sent via HTTP POST

Response (Server → Client)​

{
  "books": [
    {
      "id": 1,
      "title": "Book",
      "author": "John"
    }
  ]
}
  • Server processes and returns JSON

Important Mental Model​

  • You can think:
Client Object → JSON → Network → JSON → Server Object

  • Ignore:

    • TCP packets
    • Bit-level transmission

Where Else JSON is Used​

  • API communication
  • Config files
  • Logging systems
  • Data storage (sometimes)

Key Takeaways​

  • Serialization = convert to standard format

  • Deserialization = convert from standard format

  • JSON = most widely used format

  • Enables:

    • Cross-language communication
    • Distributed systems

Final Summary​

  • Without serialization:

    • Systems cannot communicate reliably

  • With serialization:

    • Data becomes:

      • Portable
      • Interoperable
      • Understandable across systems