API v1.0 - Stable

API Documentation

Integrate POS, accounting, and inventory management
into your applications with the Seisei API

99.9%
API Uptime
<100ms
Avg Response Time
50+
Endpoints
6
Official SDKs

Quick Start

1

Get Your API Key

Access developer settings from your dashboard and generate an API key.

Request API Key →
2

Set Up Authentication

Include Bearer authentication header in all API requests.

// API Key Authentication
const response = await fetch('https://api.seisei.tokyo/v1/orders', {
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  }
});
3

Make Your First API Call

Example: Fetching orders list

// Get orders list
const response = await fetch('https://api.seisei.tokyo/v1/orders?limit=10&status=completed', {
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY'
  }
});

const orders = await response.json();
console.log(orders.data);

API Endpoints

🛒

POS API

Sales and order management API

MethodEndpointDescription
GET/api/v1/ordersList all orders
POST/api/v1/ordersCreate a new order
GET/api/v1/orders/{id}Get order details
PUT/api/v1/orders/{id}Update an order
DELETE/api/v1/orders/{id}Cancel an order
💰

Accounting API

Accounting and financial processing API

MethodEndpointDescription
GET/api/v1/invoicesList all invoices
POST/api/v1/invoicesCreate an invoice
GET/api/v1/transactionsGet transaction history
POST/api/v1/paymentsRecord a payment
GET/api/v1/reports/financialGet financial reports
📦

Inventory API

Inventory management API

MethodEndpointDescription
GET/api/v1/inventoryList inventory items
PUT/api/v1/inventory/{id}Update stock quantity
POST/api/v1/inventory/adjustPerform stock adjustment
GET/api/v1/productsList all products
POST/api/v1/productsCreate a product
👥

Customer API

Customer management API

MethodEndpointDescription
GET/api/v1/customersList all customers
POST/api/v1/customersCreate a customer
GET/api/v1/customers/{id}Get customer details
PUT/api/v1/customers/{id}Update customer info
GET/api/v1/customers/{id}/historyGet purchase history
📊

Reports API

Analytics and reporting API

MethodEndpointDescription
GET/api/v1/reports/salesGet sales reports
GET/api/v1/reports/inventoryGet inventory reports
GET/api/v1/analytics/dashboardDashboard data
GET/api/v1/analytics/trendsTrend analysis data

Code Examples

Create an Order

// Create a new order
const newOrder = {
  customer_id: 'cus_123456',
  items: [
    { product_id: 'prod_001', quantity: 2, price: 1500 },
    { product_id: 'prod_002', quantity: 1, price: 2000 }
  ],
  payment_method: 'credit_card'
};

const response = await fetch('https://api.seisei.tokyo/v1/orders', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify(newOrder)
});

Handle Webhook Events

// Handle Webhook Events
app.post('/webhook', (req, res) => {
  const event = req.body;

  switch (event.type) {
    case 'order.created':
      handleNewOrder(event.data);
      break;
    case 'payment.completed':
      handlePayment(event.data);
      break;
    case 'inventory.low':
      handleLowInventory(event.data);
      break;
  }

  res.status(200).send('OK');
});

Official SDKs

Integrate Seisei with your preferred programming language

🟨

JavaScript / Node.js

Version: v2.1.0

View Documentation →
🐍

Python

Version: v2.0.3

View Documentation →
🐘

PHP

Version: v1.8.2

View Documentation →
💎

Ruby

Version: v1.5.0

View Documentation →
🔵

Go

Version: v1.3.1

View Documentation →

Java

Version: v1.4.0

View Documentation →

Error Codes

CodeNameDescription
400Bad RequestInvalid request format
401UnauthorizedAuthentication failed
403ForbiddenAccess denied
404Not FoundResource not found
429Rate LimitedRequest limit exceeded
500Server ErrorInternal server error

Rate Limiting

Standard Plan

  • • 1,000 requests/minute
  • • 100,000 requests/day
  • • Concurrent connections: 10

Enterprise Plan

  • • 10,000 requests/minute
  • • Unlimited requests/day
  • • Concurrent connections: Unlimited

💡 When rate limited, a 429 Too Many Requests error is returned. Check the Retry-After header for the wait time before retrying.

Start Building Today

Test the API with our free sandbox environment.
Easy migration to production when ready.