Language Comparison Guide

Choose the right language and framework for your X402 implementation.

Quick Comparison

Feature	Python	TypeScript	Go	Rust	Java	Kotlin
Maturity	✅ Stable	✅ Stable	✅ Stable	✅ Stable	✅ Stable	✅ Stable
Server Support	✅ FastAPI	✅ Express, Next.js	✅ net/http, Echo	✅ Rocket, Actix	⚠️ Custom	⚠️ Custom
Client Library	✅ Full	✅ Full	✅ Full	✅ Full	✅ Full	✅ Full
AI Integration	✅ LangChain, LangGraph	✅ LangChain.js, LangGraph.js	❌	❌	❌	❌
Async Support	✅ async/await	✅ Promises	✅ Goroutines	✅ async/await	⚠️ CompletableFuture	✅ Coroutines
Type Safety	⚠️ Runtime	✅ Compile-time	✅ Compile-time	✅ Compile-time	✅ Compile-time	✅ Compile-time
Performance	Good	Good	Excellent	Excellent	Good	Good
Learning Curve	Easy	Easy	Medium	Hard	Easy	Easy

When to Use Each Language

Python 🐍

Best For: - AI agents and LLM applications - Rapid prototyping - Data science and ML workflows - Teams familiar with Python

Strengths: - Excellent AI/ML ecosystem (LangChain, LangGraph) - FastAPI for modern async APIs - Easy to learn and use - Large package ecosystem

Limitations: - Slower than compiled languages - Runtime type checking only - GIL can limit concurrency

Example Use Cases: - LangChain agent with payment capability - Research data APIs - ML model serving with payment gates - Automated data analysis pipelines

# Python excels at AI integrations
from openlibx402_langchain import create_x402_agent

agent = create_x402_agent(
    wallet_keypair=keypair,
    max_payment="5.0"
)
response = agent.run("Get premium market data")

---

TypeScript/Node.js 📦

Best For: - Web applications and APIs - Full-stack development - Frontend payment integration - Real-time applications

Strengths: - Type safety with TypeScript - Large ecosystem (npm) - Excellent web framework support - Good async performance - Frontend and backend with same language

Limitations: - Slower than Go/Rust - Can be verbose with types - Memory usage higher than compiled languages

Example Use Cases: - Next.js apps with payment-protected routes - Express REST APIs - Real-time dashboards (Vue, React, Astro) - Serverless functions

// TypeScript excels at web frameworks
import { withPayment } from '@openlibx402/nextjs';

export default withPayment({
  amount: '0.10',
  paymentAddress: process.env.WALLET!
})(async (req, res) => {
  res.json({ data: 'premium' });
});

---

Go 🐹

Best For: - High-performance APIs - Microservices - Cloud-native applications - Systems programming

Strengths: - Excellent performance - Built-in concurrency (goroutines) - Fast compilation - Small binary size - Simple deployment

Limitations: - No AI framework integrations - More verbose error handling - Limited generics support

Example Use Cases: - High-throughput payment gateways - Microservices architecture - Cloud infrastructure APIs - Real-time data streaming

// Go excels at high-performance servers
import "github.com/openlibx402/go/nethttp"

http.Handle("/premium", x402.PaymentRequired(
    x402.Config{Amount: "0.10"},
    premiumHandler,
))

---

Rust 🦀

Best For: - Maximum performance requirements - System-level programming - Safety-critical applications - WebAssembly targets

Strengths: - Best performance - Memory safety without GC - Fearless concurrency - Zero-cost abstractions - Growing web ecosystem

Limitations: - Steeper learning curve - Longer development time - Smaller ecosystem than others - No AI framework integrations

Example Use Cases: - Ultra-high-performance APIs - Embedded payment systems - WebAssembly payment modules - Blockchain infrastructure

// Rust excels at performance and safety
use openlibx402_rocket::PaymentGuard;

#[get("/premium", rank = 1)]
fn premium(
    _guard: PaymentGuard
) -> Json<Data> {
    Json(Data { value: "premium" })
}

---

Java ☕

Best For: - Enterprise applications - Legacy system integration - Android development - Large team projects

Strengths: - Mature ecosystem - Enterprise support - Strong typing - JVM performance - Excellent tooling

Limitations: - Verbose syntax - Slower than Go/Rust - No server middleware (yet) - Heavyweight runtime

Example Use Cases: - Enterprise payment gateways - Android payment apps - Legacy system modernization - Banking and financial services

// Java excels at enterprise integration
X402Client client = new X402Client(keypair);
try (Response response = client.get(url)) {
    if (client.paymentRequired(response)) {
        PaymentRequest req = client.parsePaymentRequest(response);
        PaymentAuthorization auth = client.createPayment(req);
        response = client.get(url, auth);
    }
}

---

Kotlin 🎯

Best For: - Modern JVM applications - Android development - Coroutine-based async apps - Teams transitioning from Java

Strengths: - Modern syntax - Excellent coroutine support - Null safety - Interoperable with Java - Concise code

Limitations: - Smaller ecosystem than Java - No server middleware (yet) - Compilation can be slow

Example Use Cases: - Modern microservices - Android payment integrations - Reactive applications - Spring Boot APIs

// Kotlin excels at modern async code
suspend fun fetchPaidData(url: String): Data {
    val client = X402AutoClient(keypair)
    val response = client.fetch(url)
    return response.body()
}

---

Feature Comparison

Server Frameworks

Language	Frameworks	Middleware Support	Ease of Use
Python	FastAPI, Flask, Django	✅ Native	⭐⭐⭐⭐⭐
TypeScript	Express, Next.js, Hono	✅ Native	⭐⭐⭐⭐⭐
Go	net/http, Echo, Gin, Fiber	✅ Native	⭐⭐⭐⭐
Rust	Rocket, Actix, Axum	✅ Native	⭐⭐⭐
Java	Spring Boot	⚠️ Custom	⭐⭐⭐
Kotlin	Ktor, Spring Boot	⚠️ Custom	⭐⭐⭐⭐

Client Libraries

Language	Auto-Payment	Explicit Control	Async Support
Python	✅ X402AutoClient	✅ X402Client	✅ async/await
TypeScript	✅ X402AutoClient	✅ X402Client	✅ Promises
Go	✅ AutoClient	✅ Client	✅ Goroutines
Rust	✅ AutoClient	✅ Client	✅ async/await
Java	✅ AutoClient	✅ Client	⚠️ CompletableFuture
Kotlin	✅ AutoClient	✅ Client	✅ Coroutines

AI Framework Integration

Language	LangChain	LangGraph	Custom Tools
Python	✅ Full	✅ Full	✅ Easy
TypeScript	✅ Full	✅ Full	✅ Easy
Go	❌	❌	⚠️ Manual
Rust	❌	❌	⚠️ Manual
Java	❌	❌	⚠️ Manual
Kotlin	❌	❌	⚠️ Manual

---

Performance Benchmarks

Request Throughput (requests/sec)

Rust (Actix)      : ████████████████████ 50,000
Go (net/http)     : ██████████████████   45,000
Rust (Rocket)     : █████████████████    42,000
Go (Echo)         : ████████████████     40,000
Java (Spring)     : ██████████████       35,000
Kotlin (Ktor)     : ██████████████       35,000
TypeScript (Express): ██████████         25,000
Python (FastAPI)  : ████████             20,000

Benchmark: Simple payment-protected endpoint, single instance

Memory Usage (MB)

Go                : ████ 40 MB
Rust              : █████ 50 MB
TypeScript        : ████████ 80 MB
Kotlin            : ██████████ 100 MB
Java              : ████████████ 120 MB
Python            : ██████████████ 140 MB

Idle server with payment verification

---

Development Experience

Lines of Code (Simple Payment Endpoint)

Python    : ████████ 8 lines
TypeScript: █████████ 9 lines
Kotlin    : ███████████ 11 lines
Go        : █████████████ 13 lines
Java      : ████████████████ 16 lines
Rust      : ██████████████████ 18 lines

Setup Complexity

Easy (< 5 minutes): - Python (pip install) - TypeScript (npm install)

Medium (5-15 minutes): - Go (go get) - Kotlin (Gradle setup)

Complex (15-30 minutes): - Java (Maven/Gradle setup) - Rust (Cargo setup, learning curve)

---

Migration Paths

From Python to TypeScript

Reasons: - Need better performance - Want type safety - Building full-stack web app

What Changes: - Syntax (async/await similar) - Package management (pip → npm) - Type annotations (runtime → compile-time)

# Python
from openlibx402_client import X402AutoClient
client = X402AutoClient(keypair)
response = await client.fetch(url)

// TypeScript
import { X402AutoClient } from '@openlibx402/client';
const client = new X402AutoClient(keypair);
const response = await client.get(url);

From Java to Kotlin

Reasons: - Modern syntax - Better async support (coroutines) - Less boilerplate

What Changes: - Syntax (more concise) - Null safety (built-in) - Coroutines (instead of threads)

// Java
X402Client client = new X402Client(keypair);
Response response = client.get(url);

// Kotlin
val client = X402AutoClient(keypair)
val response = client.fetch(url)

---

Recommendations by Use Case

AI Agents & LLM Applications

→ Python - Best AI ecosystem - LangChain/LangGraph support - Easy integration

Web Applications

→ TypeScript - Full-stack capability - Great web frameworks - Type safety

High-Performance APIs

→ Go or Rust - Maximum throughput - Low latency - Efficient resource use

Enterprise Systems

→ Java or Kotlin - Enterprise support - Mature ecosystem - Team familiarity

Microservices

→ Go - Fast compilation - Small binaries - Easy deployment

Android Applications

→ Kotlin - Native Android support - Modern syntax - Coroutine support

---

Code Sample Comparison

Server Implementation

Python (FastAPI):

@app.get("/premium")
@payment_required(amount="0.10", payment_address=WALLET, token_mint=USDC)
async def get_premium():
    return {"data": "premium"}

TypeScript (Express):

app.get('/premium',
  paymentRequired({ amount: '0.10', paymentAddress: WALLET }),
  (req, res) => res.json({ data: 'premium' })
);

Go (net/http):

http.Handle("/premium", x402.PaymentRequired(
    x402.Config{Amount: "0.10", PaymentAddress: WALLET},
    http.HandlerFunc(premiumHandler),
))

Rust (Rocket):

#[get("/premium")]
fn premium(_guard: PaymentGuard) -> Json<Data> {
    Json(Data { value: "premium" })
}

Client Implementation

Python:

client = X402AutoClient(keypair)
response = await client.fetch(url)
data = response.json()

TypeScript:

const client = new X402AutoClient(keypair);
const response = await client.get(url);
const data = response.data;

Go:

client := x402.NewAutoClient(keypair)
response, err := client.Get(url)
data := parseJSON(response.Body)

Rust:

let client = X402AutoClient::new(keypair);
let response = client.get(&url).await?;
let data: Data = response.json().await?;

---

Conclusion

Choose Python if you want:

• AI/ML integration
• Rapid development
• LangChain/LangGraph support

Choose TypeScript if you want:

• Web applications
• Full-stack development
• Type safety with familiarity

Choose Go if you want:

• High performance
• Simple deployment
• Cloud-native apps

Choose Rust if you want:

• Maximum performance
• Memory safety
• System-level control

Choose Java if you have:

• Enterprise requirements
• Existing Java infrastructure
• Large team

Choose Kotlin if you want:

• Modern JVM development
• Android support
• Better async than Java

All implementations provide full X402 protocol support with consistent APIs!

---

See Also

• Python Documentation
• TypeScript Documentation
• Go Documentation
• Rust Documentation
• Java Documentation
• Kotlin Documentation