What is the difference between net/http and third-party HTTP clients in Go?

When building web scrapers or consuming APIs in Go, you'll need to make HTTP requests. Go provides a built-in net/http package that covers most basic needs, but third-party libraries often offer additional features and convenience methods. Understanding the differences between these options will help you choose the right tool for your specific use case.

Go's Built-in net/http Package

The net/http package is part of Go's standard library and provides a robust foundation for HTTP operations. It's battle-tested, well-documented, and doesn't add external dependencies to your project.

Basic GET Request with net/http

package main

import (
    "fmt"
    "io"
    "net/http"
    "time"
)

func main() {
    // Create a custom client with timeout
    client := &http.Client{
        Timeout: 30 * time.Second,
    }

    resp, err := client.Get("https://api.example.com/data")
    if err != nil {
        fmt.Printf("Error making request: %v\n", err)
        return
    }
    defer resp.Body.Close()

    body, err := io.ReadAll(resp.Body)
    if err != nil {
        fmt.Printf("Error reading response: %v\n", err)
        return
    }

    fmt.Printf("Status: %s\n", resp.Status)
    fmt.Printf("Body: %s\n", string(body))
}

POST Request with JSON Data

package main

import (
    "bytes"
    "encoding/json"
    "fmt"
    "net/http"
)

type RequestData struct {
    Name  string `json:"name"`
    Email string `json:"email"`
}

func main() {
    data := RequestData{
        Name:  "John Doe",
        Email: "john@example.com",
    }

    jsonData, err := json.Marshal(data)
    if err != nil {
        fmt.Printf("Error marshaling JSON: %v\n", err)
        return
    }

    req, err := http.NewRequest("POST", "https://api.example.com/users", bytes.NewBuffer(jsonData))
    if err != nil {
        fmt.Printf("Error creating request: %v\n", err)
        return
    }

    req.Header.Set("Content-Type", "application/json")
    req.Header.Set("User-Agent", "MyApp/1.0")

    client := &http.Client{}
    resp, err := client.Do(req)
    if err != nil {
        fmt.Printf("Error making request: %v\n", err)
        return
    }
    defer resp.Body.Close()

    fmt.Printf("Status Code: %d\n", resp.StatusCode)
}

Popular Third-Party HTTP Clients

1. Resty - User-Friendly REST Client

Resty is one of the most popular third-party HTTP clients for Go, offering a chainable API and many convenience features.

package main

import (
    "fmt"
    "github.com/go-resty/resty/v2"
)

type User struct {
    Name  string `json:"name"`
    Email string `json:"email"`
}

func main() {
    client := resty.New()

    // GET request with automatic JSON unmarshaling
    var users []User
    resp, err := client.R().
        SetResult(&users).
        Get("https://api.example.com/users")

    if err != nil {
        fmt.Printf("Error: %v\n", err)
        return
    }

    fmt.Printf("Status: %s\n", resp.Status())
    fmt.Printf("Users: %+v\n", users)

    // POST request with automatic JSON marshaling
    newUser := User{Name: "Jane Doe", Email: "jane@example.com"}
    resp, err = client.R().
        SetBody(newUser).
        SetHeader("Content-Type", "application/json").
        Post("https://api.example.com/users")

    if err != nil {
        fmt.Printf("Error: %v\n", err)
        return
    }

    fmt.Printf("Created user, status: %s\n", resp.Status())
}

2. Fasthttp - High-Performance HTTP Client

Fasthttp is designed for high-performance scenarios and can be significantly faster than net/http in certain use cases.

package main

import (
    "fmt"
    "github.com/valyala/fasthttp"
    "time"
)

func main() {
    // Create a custom client with timeout
    client := &fasthttp.Client{
        ReadTimeout:  30 * time.Second,
        WriteTimeout: 30 * time.Second,
    }

    req := fasthttp.AcquireRequest()
    resp := fasthttp.AcquireResponse()
    defer fasthttp.ReleaseRequest(req)
    defer fasthttp.ReleaseResponse(resp)

    req.SetRequestURI("https://api.example.com/data")
    req.Header.SetMethod("GET")
    req.Header.Set("User-Agent", "FastHTTP Client")

    err := client.Do(req, resp)
    if err != nil {
        fmt.Printf("Error making request: %v\n", err)
        return
    }

    fmt.Printf("Status Code: %d\n", resp.StatusCode())
    fmt.Printf("Body: %s\n", resp.Body())
}

3. Gentleman - Extensible HTTP Client

Gentleman provides a plugin-based architecture for extending HTTP client functionality.

package main

import (
    "fmt"
    "gopkg.in/h2non/gentleman.v2"
    "gopkg.in/h2non/gentleman.v2/plugins/auth"
    "gopkg.in/h2non/gentleman.v2/plugins/timeout"
    "time"
)

func main() {
    cli := gentleman.New()
    cli.URL("https://api.example.com")
    cli.Use(timeout.Request(30 * time.Second))
    cli.Use(auth.Basic("username", "password"))

    res, err := cli.Request().
        Path("/users").
        Method("GET").
        Send()

    if err != nil {
        fmt.Printf("Error: %v\n", err)
        return
    }

    fmt.Printf("Status: %d\n", res.StatusCode)
    fmt.Printf("Body: %s\n", res.String())
}

Key Differences and Comparison

1. API Design and Ease of Use

net/http: Verbose but explicit. Requires more boilerplate code for common operations like JSON handling, but gives you full control over every aspect of the request.

Third-party clients: Usually offer more concise, chainable APIs that reduce boilerplate code. Features like automatic JSON marshaling/unmarshaling make common tasks much simpler.

2. Performance Characteristics

net/http: Good general-purpose performance with reasonable memory usage. Uses Go's built-in connection pooling and keep-alive mechanisms.

Fasthttp: Significantly faster in high-throughput scenarios. Uses object pooling and zero-allocation techniques but has a different API that's not compatible with net/http.

Resty/Gentleman: Built on top of net/http, so performance is similar with slight overhead for convenience features.

3. Feature Richness

net/http: Basic HTTP functionality. You need to implement features like retries, circuit breakers, and advanced authentication manually.

Third-party clients: Often include built-in features like: - Automatic retries with exponential backoff - Request/response middleware - Built-in authentication methods - Automatic JSON handling - Request debugging and logging

4. Dependencies and Maintenance

net/http: Zero external dependencies, maintained by the Go team, guaranteed backward compatibility.

Third-party clients: Additional dependencies that need to be managed and updated. Quality and maintenance vary by project.

When to Use Each Option

Choose net/http when:

• Building libraries that others will use (to avoid forcing dependencies)
• Working in environments with strict dependency restrictions
• Need maximum control over HTTP behavior
• Building simple applications with basic HTTP needs
• Performance requirements are moderate

Choose third-party clients when:

• Rapid development is prioritized over minimal dependencies
• You need advanced features like built-in retries or circuit breakers
• Working extensively with REST APIs that benefit from JSON automation
• Team prefers more expressive, fluent APIs
• Building web scrapers that need robust error handling capabilities

Advanced Configuration Examples

Connection Pooling with net/http

package main

import (
    "net/http"
    "time"
)

func createOptimizedClient() *http.Client {
    transport := &http.Transport{
        MaxIdleConns:        100,
        MaxIdleConnsPerHost: 10,
        IdleConnTimeout:     90 * time.Second,
        DisableKeepAlives:   false,
    }

    return &http.Client{
        Transport: transport,
        Timeout:   30 * time.Second,
    }
}

Retry Logic with Resty

package main

import (
    "github.com/go-resty/resty/v2"
    "time"
)

func createRestyClientWithRetries() *resty.Client {
    client := resty.New()

    client.SetRetryCount(3).
        SetRetryWaitTime(5 * time.Second).
        SetRetryMaxWaitTime(20 * time.Second).
        AddRetryCondition(func(r *resty.Response, err error) bool {
            return r.StatusCode() >= 500
        })

    return client
}

Best Practices for Web Scraping

When building web scrapers in Go, consider these practices regardless of which HTTP client you choose:

1. Always set timeouts to prevent hanging requests
2. Implement proper error handling and retry logic for resilient scraping
3. Respect rate limits to avoid being blocked by target websites
4. Use appropriate User-Agent headers to identify your scraper
5. Handle cookies and sessions properly for sites that require them

For complex scraping scenarios that require JavaScript execution, you might need to integrate with browser automation tools, similar to how Puppeteer handles dynamic content.

Conclusion

The choice between net/http and third-party HTTP clients depends on your specific requirements. For simple applications or libraries, net/http provides everything you need without external dependencies. For rapid development of feature-rich applications, third-party clients like Resty offer significant productivity benefits. For high-performance scenarios, Fasthttp can provide substantial speed improvements at the cost of API compatibility.

Consider your project's constraints around dependencies, performance requirements, development speed, and long-term maintenance when making this decision. Many successful Go applications use net/http exclusively, while others benefit greatly from the additional features provided by third-party alternatives.