Backend

Gin

A fast HTTP framework for Go with a router, middleware and convenient JSON handling.

What it is

Gin is a thin layer over net/http with a fast radix-tree router. It adds route groups, middleware, JSON binding and validation.

The framework is minimal: you choose the ORM and project structure. That is a familiar approach for Go developers.

A Go binary compiles to a single file, starts fast and uses little memory, so Gin is often chosen for microservices and APIs.

Use it when

  • REST APIs and microservices in Go with a focus on speed.
  • You need simple routes and middleware without a heavy framework.
  • Small containers and fast cold starts.

Avoid it when

  • You need a full stack with admin and ORM out of the box: Django, Rails, Laravel.
  • For simple cases, the standard net/http in recent Go versions is enough.

Key concepts

Context
*gin.Context carries the request, response and values between middleware.
Router group
A group of routes with a shared prefix and middleware.
Binding
Parsing JSON or a form into a struct with tag-based validation.
Middleware
A function that calls c.Next() or c.Abort().

Example

The simplest server with one route.

Interview questions

  1. 1. Why is Gin fast?

    A radix-tree router with no allocations on the hot path and less overhead than large frameworks. Go itself also handles networking quickly.

  2. 2. How does middleware work in Gin?

    It is a gin.HandlerFunc run before or after the handler. c.Next() passes control on, c.Abort() stops the chain.

  3. 3. How do you validate input JSON?

    Describe a struct with binding:"required" tags and call c.ShouldBindJSON(&dto). A validation failure comes back as an error.

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