Sei API Quick Start Guide

BlockEden.xyz provides high-performance infrastructure for Sei, the first parallelized EVM blockchain. Access Sei's unique dual-architecture through our enterprise-grade API endpoints with sub-second response times.

What is Sei?

Sei is a parallelized EVM blockchain that combines Ethereum compatibility with Cosmos SDK functionality:

Sub-second Finality: Fastest transaction confirmation in the industry
Parallelized Execution: Optimistic parallel processing for maximum throughput
Dual Architecture: Both EVM (Ethereum) and Cosmos SDK APIs
High Performance: Thousands of transactions per second
Full EVM Compatibility: Use existing Ethereum tools and wallets

API Endpoints

BlockEden.xyz supports all Sei API types through our global infrastructure:

Mainnet

EVM JSON-RPC: https://api.blockeden.xyz/sei/<your-api-key>
WebSocket: wss://api.blockeden.xyz/sei/<your-api-key>
Cosmos REST: https://api.blockeden.xyz/sei/<your-api-key>/cosmos/
Tendermint RPC: https://api.blockeden.xyz/sei/<your-api-key>/tm/

Quick Start

Step 1: Get Your API Key

Visit BlockEden.xyz Dashboard
Create a new API key for Sei
Select Mainnet

Step 2: Test Connection

EVM JSON-RPC (Ethereum Compatible)

curl -X POST https://api.blockeden.xyz/sei/<your-api-key> \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_blockNumber",
    "params": [],
    "id": 1
  }'

Cosmos REST API

curl -X GET https://api.blockeden.xyz/sei/<your-api-key>/cosmos/bank/v1beta1/supply

Tendermint RPC

curl -X POST https://api.blockeden.xyz/sei/<your-api-key>/tm \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "status",
    "params": [],
    "id": 1
  }'

Supported API Methods

EVM JSON-RPC Methods

All standard Ethereum JSON-RPC methods are supported:

Account Methods: eth_getBalance, eth_getTransactionCount, eth_getCode
Block Methods: eth_blockNumber, eth_getBlockByNumber, eth_getBlockByHash
Transaction Methods: eth_sendRawTransaction, eth_getTransactionReceipt
Contract Methods: eth_call, eth_estimateGas, eth_getLogs
Gas Methods: eth_gasPrice, eth_feeHistory, eth_maxPriorityFeePerGas
Network Methods: eth_chainId, net_version

Cosmos REST Endpoints

Bank Module: /cosmos/bank/v1beta1/* - Token balances and transfers
Staking Module: /cosmos/staking/v1beta1/* - Validator and delegation info
Governance Module: /cosmos/gov/v1beta1/* - Proposals and voting
Distribution Module: /cosmos/distribution/v1beta1/* - Rewards and commission
Auth Module: /cosmos/auth/v1beta1/* - Account information

Tendermint RPC Methods

Blockchain Info: status, health, net_info
Block Data: block, block_by_hash, blockchain
Transaction Data: tx, tx_search, broadcast_tx_sync
Consensus: validators, consensus_state

Code Examples

JavaScript/TypeScript

// EVM (Ethereum-style) usage
import { ethers } from 'ethers';

const provider = new ethers.JsonRpcProvider('https://api.blockeden.xyz/sei/<your-api-key>');

// Get latest block
const blockNumber = await provider.getBlockNumber();
console.log('Latest block:', blockNumber);

// Get account balance
const balance = await provider.getBalance('0x742D5Cc6bF2442E8C7c74c7b4Be6AB9d6f10f5B4');
console.log('Balance:', ethers.formatEther(balance), 'SEI');

// Cosmos SDK usage
import { StargateClient } from '@cosmjs/stargate';

const client = await StargateClient.connect('https://api.blockeden.xyz/sei/<your-api-key>');

// Get account balance
const balance = await client.getBalance('sei1abc...xyz', 'usei');
console.log('Balance:', balance.amount, balance.denom);

Python

import requests

# EVM JSON-RPC
def get_block_number():
    url = "https://api.blockeden.xyz/sei/<your-api-key>"
    payload = {
        "jsonrpc": "2.0",
        "method": "eth_blockNumber",
        "params": [],
        "id": 1
    }
    response = requests.post(url, json=payload)
    return int(response.json()['result'], 16)

# Cosmos REST API
def get_bank_balance(address):
    url = f"https://api.blockeden.xyz/sei/<your-api-key>/cosmos/bank/v1beta1/balances/{address}"
    response = requests.get(url)
    return response.json()

Go

package main

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

type RPCRequest struct {
    JSONRPC string      `json:"jsonrpc"`
    Method  string      `json:"method"`
    Params  []interface{} `json:"params"`
    ID      int         `json:"id"`
}

func getBlockNumber() {
    url := "https://api.blockeden.xyz/sei/<your-api-key>"

    req := RPCRequest{
        JSONRPC: "2.0",
        Method:  "eth_blockNumber",
        Params:  []interface{}{},
        ID:      1,
    }

    jsonData, _ := json.Marshal(req)
    resp, _ := http.Post(url, "application/json", bytes.NewBuffer(jsonData))
    defer resp.Body.Close()

    // Handle response...
}

Authentication

All API requests require your API key in the URL path:

https://api.blockeden.xyz/sei/<your-api-key>/[optional-path]

Examples:

EVM: https://api.blockeden.xyz/sei/abc123/
Cosmos: https://api.blockeden.xyz/sei/abc123/cosmos/bank/v1beta1/supply
Tendermint: https://api.blockeden.xyz/sei/abc123/tm

Rate Limits

Free Tier: 100 requests/second, 86,400 requests/day
Pro Tier: 1,000 requests/second, 10M requests/day
Enterprise: Custom limits based on your needs

Rate limit headers are included in responses:

X-RateLimit-Limit: 100
X-RateLimit-Remaining: 99
X-RateLimit-Reset: 1640995200

Network Information

Mainnet (Pacific-1)

Chain ID: pacific-1 (Cosmos), 1329 (EVM)
Native Token: SEI (6 decimals)
Block Time: ~0.4 seconds
Explorer: https://seitrace.com

WebSocket Subscriptions

Real-time data streaming for both EVM and Tendermint events:

// EVM event subscriptions
const ws = new WebSocket('wss://api.blockeden.xyz/sei/<your-api-key>');

ws.onopen = () => {
  ws.send(JSON.stringify({
    jsonrpc: '2.0',
    method: 'eth_subscribe',
    params: ['newHeads'],
    id: 1
  }));
};

ws.onmessage = (event) => {
  const data = JSON.parse(event.data);
  console.log('New block:', data);
};

Error Handling

Common HTTP Status Codes

200: Success
400: Bad Request (invalid JSON or parameters)
401: Unauthorized (invalid API key)
429: Too Many Requests (rate limit exceeded)
500: Internal Server Error

JSON-RPC Error Codes

-32700: Parse error
-32600: Invalid Request
-32601: Method not found
-32602: Invalid params
-32603: Internal error
-32000: Server error

Example Error Response

{
  "jsonrpc": "2.0",
  "error": {
    "code": -32602,
    "message": "Invalid params",
    "data": "Missing required parameter"
  },
  "id": 1
}

Best Practices

Performance Optimization

Use WebSockets for real-time data instead of polling
Batch requests when possible to reduce latency
Cache responses for frequently accessed data
Use appropriate timeouts (recommend 30s for HTTP)

Error Handling

async function makeRequest(method, params) {
  try {
    const response = await fetch(endpoint, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ jsonrpc: '2.0', method, params, id: 1 })
    });

    if (!response.ok) {
      throw new Error(`HTTP ${response.status}: ${response.statusText}`);
    }

    const data = await response.json();
    if (data.error) {
      throw new Error(`RPC Error ${data.error.code}: ${data.error.message}`);
    }

    return data.result;
  } catch (error) {
    console.error('API request failed:', error);
    throw error;
  }
}

Retry Logic

async function withRetry(fn, maxRetries = 3) {
  for (let i = 0; i < maxRetries; i++) {
    try {
      return await fn();
    } catch (error) {
      if (i === maxRetries - 1) throw error;
      await new Promise(resolve => setTimeout(resolve, 1000 * Math.pow(2, i)));
    }
  }
}

Next Steps

Explore the Sei JSON-RPC API Reference for complete EVM method documentation
Learn about Sei Cosmos REST API for native Cosmos functionality
Check out Sei WebSocket Guide for real-time data streaming
Visit BlockEden.xyz Dashboard to monitor your usage

Support

📧 Email: support@blockeden.xyz
💬 Discord: Join our community
🐦 Twitter: @BlockEdenHQ
📊 Status Page: status.blockeden.xyz
📖 API Documentation: docs.blockeden.xyz

Share on Twitter

What is Sei?​

API Endpoints​

Mainnet​

Quick Start​

Step 1: Get Your API Key​

Step 2: Test Connection​

EVM JSON-RPC (Ethereum Compatible)​

Cosmos REST API​

Tendermint RPC​

Supported API Methods​

EVM JSON-RPC Methods​

Cosmos REST Endpoints​

Tendermint RPC Methods​

Code Examples​

JavaScript/TypeScript​

Python​

Go​

Authentication​

Rate Limits​

Network Information​

Mainnet (Pacific-1)​

WebSocket Subscriptions​

Error Handling​

Common HTTP Status Codes​

JSON-RPC Error Codes​

Example Error Response​

Best Practices​

Performance Optimization​

Error Handling​

Retry Logic​

Next Steps​

Support​

What is Sei?

API Endpoints

Mainnet

Quick Start

Step 1: Get Your API Key

Step 2: Test Connection

EVM JSON-RPC (Ethereum Compatible)

Cosmos REST API

Tendermint RPC

Supported API Methods

EVM JSON-RPC Methods

Cosmos REST Endpoints

Tendermint RPC Methods

Code Examples

JavaScript/TypeScript

Python

Go

Authentication

Rate Limits

Network Information

Mainnet (Pacific-1)

WebSocket Subscriptions

Error Handling

Common HTTP Status Codes

JSON-RPC Error Codes

Example Error Response

Best Practices

Performance Optimization

Error Handling

Retry Logic

Next Steps

Support