Overview

Web3SDK is a Web3 payment platform for small and medium merchants worldwide. Merchants collect USDT / USDC through the platform; the platform watches chains, handles confirmations, callbacks and reconciliation; merchants create orders, ship goods and reconcile inside their own systems.

The platform has four parts. Once you understand how they divide the work, every page in these docs has an obvious place.

The four parts

Part	Who it's for	How it's reached	Authentication
Open API	Your server	POST /api/pay/open/createOrder, GET /api/pay/open/queryOrder	Request header X-Pay-Api-Key
Checkout (buyer side)	Your buyers	Payment counter link and QR, public checkout endpoints	No login; protected by one-time tickets and rate limits
Merchant console	Your operations	Console pages and merchant-side endpoints after login	Username and password exchanged for a JWT
Platform configuration	Us	Chains and tokens, rates and rules, merchant authorization	Internal; not exposed

Merchants touch the first two day to day; the third is where you configure addresses, view orders and reconcile.

Data flow

The full path of one payment:

Your server ──(1) create order──▶ Open API
      │                                │
      │                                ▼
      │                    platform order + pay address + identify data
      │                                │
   buyer ◀──(2) scans and pays─────────┘
      │
      ▼
  on-chain tx ──(3) scanner matches──▶ order: submitted → confirmed
                                           │
your server ◀──(4) callback notifyUrl──────┘
      │
      └──(5) your server queries the API to confirm (query is authoritative)

Start here

Quickstart (5 min)

Register for a KEY, configure an address, create your first order, receive the callback. Every step has a copy-paste example.

Concepts

Merchant number, collection address, checkout, Open API, chains and tokens, callbacks — build the vocabulary before reading the endpoints.

Auth and signatures

How the Open API authenticates, how callbacks are verified, and how keys are rotated.

Create order

Fields, amount conventions, the idempotency key, and the response shape.

Callbacks and verification

When callbacks fire, how often they retry, and how to avoid shipping twice.

Errors

Common symptoms and the order to troubleshoot them in, organised by readable category names.

Which path fits you

Writing your own backend

Start with Auth and signatures, then Create order and Callbacks.

Frontend framework project

See React, Vue 3 or Next.js. Order creation stays on the server.

Mobile app

See Android or iOS for wallet handoff and callback handling.

Platforms and storefronts

Telegram Bot, Mini App, E-commerce plugins.

One rule that runs through everything

The API KEY belongs on your server only. In every SDK example the order-creation call is made by your backend; the frontend only displays the amount, hands off to the wallet and reports the transaction hash. Put the KEY in a browser or an app bundle and you have effectively published the key to your callback channel.