Quick Start

import express from 'express'
import { paymentMiddleware } from '@t402/express'
import { ExactEvmScheme } from '@t402/evm'
 
const app = express()
 
// Add payment middleware
app.use(paymentMiddleware({
  'GET /api/premium': {
    price: '$0.01',
    network: 'eip155:8453', // Base
    payTo: '0xYourAddress...',
    description: 'Premium API access'
  }
}))
 
app.get('/api/premium', (req, res) => {
  res.json({ data: 'Premium content!' })
})
 
app.listen(3000)

import { Hono } from 'hono'
import { paymentMiddleware } from '@t402/hono'
 
const app = new Hono()
 
app.use('/api/*', paymentMiddleware({
  'GET /api/premium': {
    price: '$0.01',
    network: 'eip155:8453',
    payTo: '0xYourAddress...',
  }
}))
 
app.get('/api/premium', (c) => c.json({ data: 'Premium content!' }))
 
export default app

from fastapi import FastAPI
from t402.fastapi.middleware import require_payment
 
app = FastAPI()
 
app.middleware("http")(
    require_payment(
        price="0.01",
        pay_to_address="0xYourAddress..."
    )
)
 
@app.get("/api/premium")
async def premium():
    return {"data": "Premium content!"}

package main
 
import (
    "github.com/gin-gonic/gin"
    t402gin "github.com/t402-io/t402/sdks/go/http/gin"
)
 
func main() {
    r := gin.Default()
    r.Use(t402gin.PaymentMiddleware(t402gin.Config{
        PayTo:   "0xYourAddress...",
        Network: "eip155:8453",
    }))
    r.GET("/api/premium", func(c *gin.Context) {
        c.JSON(200, gin.H{"data": "Premium content!"})
    })
    r.Run(":3000")
}

# application.yml
t402:
  enabled: true
  facilitator-url: https://facilitator.t402.io
  network: eip155:8453
  pay-to: "0xYourAddress..."
  asset: "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"

@RestController
public class ApiController {
    @GetMapping("/api/premium")
    public Map<String, String> premium() {
        return Map.of("data", "Premium content!");
    }
}

import { t402Client, wrapFetchWithPayment } from '@t402/fetch'
import { registerExactEvmScheme } from '@t402/evm/exact/client'
import { privateKeyToAccount } from 'viem/accounts'
 
// Create and configure client
const client = new t402Client()
registerExactEvmScheme(client, {
  signer: privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`)
})
 
// Wrap fetch to automatically handle payments
const fetchWithPayment = wrapFetchWithPayment(fetch, client)
 
// Make requests - payments are handled automatically!
const response = await fetchWithPayment('https://api.example.com/api/premium')
const data = await response.json()

from t402 import T402Client
 
client = T402Client(private_key="0x...")
 
response = client.get("https://api.example.com/api/premium")
data = response.json()

import "github.com/t402-io/t402/sdks/go/client"
 
c := client.New(privateKey)
 
resp, err := c.Get("https://api.example.com/api/premium")

import io.t402.crypto.EvmSigner;
import io.t402.client.T402HttpClient;
 
EvmSigner signer = EvmSigner.fromPrivateKey("0x...", 8453, "https://mainnet.base.org");
T402HttpClient client = new T402HttpClient(signer);
 
var response = client.get("https://api.example.com/api/premium");

# Core + EVM (most common)
pnpm add @t402/core @t402/evm
 
# With Express middleware
pnpm add @t402/core @t402/evm @t402/express
 
# Full client setup with fetch wrapper
pnpm add @t402/core @t402/evm @t402/fetch
 
# All mechanism packages (multi-chain)
pnpm add @t402/core @t402/evm @t402/svm @t402/ton @t402/tron @t402/near @t402/aptos @t402/tezos @t402/polkadot @t402/stacks @t402/cosmos @t402/stellar

pip install t402
# or: uv add t402 / poetry add t402

go get github.com/t402-io/t402/sdks/go

<dependency>
    <groupId>io.t402</groupId>
    <artifactId>t402</artifactId>
    <version>1.13.1</version>
</dependency>