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polymarket_setup.md

Polymarket CLOB API Trading Setup Guide

A complete guide to setting up automated trading on Polymarket using the CLOB (Central Limit Order Book) API with an EOA (Externally Owned Account) Metamask wallet.

Understanding the Architecture
Prerequisites
High-Level Overview
Step-by-Step Setup
Verification Scripts
Common Issues & Solutions
Reference

Understanding the Architecture

Account Structure

┌─────────────────────────────────────────────────────────┐
│ YOUR METAMASK EOA (Externally Owned Account)            │
├─────────────────────────────────────────────────────────┤
│ Private Key: 0x1a4aaa20c0...                            │
│ Address:     0xb99107501d...                            │
│ Purpose:     Signs orders, holds funds                  │
│ Type:        Simple wallet you control directly         │
└─────────────────────────────────────────────────────────┘
                              │
                              │ For API trading
                              ▼
┌─────────────────────────────────────────────────────────┐
│ POLYMARKET CLOB API                                      │
├─────────────────────────────────────────────────────────┤
│ Uses your EOA to:                                        │
│ - Sign EIP-712 order messages                           │
│ - Execute trades directly from your wallet              │
│ - Hold outcome tokens in your wallet                    │
│ - No deposit/withdrawal needed                          │
└─────────────────────────────────────────────────────────┘

vs.

┌─────────────────────────────────────────────────────────┐
│ POLYMARKET WEBSITE (Smart Contract Wallet)              │
├─────────────────────────────────────────────────────────┤
│ Profile Address:  0x7f2D93f56d... (proxy contract)      │
│ Deposit Address:  0xC514209f23... (deposit contract)    │
│ Purpose:          Website UI trading only               │
│ Note:             Separate from API trading!            │
└─────────────────────────────────────────────────────────┘

Key Insight: API trading uses your EOA wallet directly. The Polymarket website uses a separate smart contract wallet system. These are completely independent!

Prerequisites

Required Tools

MetaMask browser extension or mobile app
Python 3.8+ (for setup scripts)
Rust (for the trading bot)
Some ETH on Ethereum mainnet or another chain (for bridging to Polygon)

Required Tokens on Polygon

USDC.e (bridged USDC) - for trading
- Contract: 0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174
- This is the OLD USDC that Polymarket uses
MATIC/POL - for gas fees
- Need ~0.1 MATIC minimum (gas is very cheap on Polygon)

High-Level Overview

The Complete Flow

1. Get MetaMask wallet address and private key
   └─> 0xb99107501d... (your address)
   └─> 0x1a4aaa20c0... (your private key)

2. Fund your wallet on Polygon network
   ├─> Bridge ETH → Polygon → swap to USDC.e
   ├─> Or buy USDC directly and withdraw to Polygon
   └─> Get free MATIC from faucet

3. Approve Polymarket contracts to spend your USDC.e
   └─> One-time setup per exchange contract

4. Register your wallet with Polymarket API
   └─> Derives API credentials for authentication

5. Start trading!
   └─> Place orders directly from your wallet

Step-by-Step Setup

Step 1: Get Your MetaMask Credentials

1.1 Get Your Wallet Address

Open MetaMask
Click on your account name at the top
Your address is shown (42 characters starting with 0x)
Example: 0xb99107501dFFd0F165782f92133048875053Dc5a

1.2 Export Your Private Key

⚠️ SECURITY WARNING: Never share your private key! Keep it secure!

In MetaMask, click the three dots (⋮)
Account details
Show private key
Enter your MetaMask password
Copy the private key (64 hex characters + 0x)
Example: 0x1a4aaa20c0...

1.3 Create Your `.env` File

# Polymarket Trading Credentials
POLY_PRIVATE_KEY=0x1a4aaa20c0...  # Your MetaMask private key
POLY_FUNDER=0xb99107501d...       # Your MetaMask address (same wallet)

# Polygon RPC (optional - uses public RPC by default)
POLYGON_RPC=https://polygon-rpc.com

Step 2: Fund Your Polygon Wallet

You need USDC.e (not regular USDC!) on the Polygon network.

Option A: Bridge from Ethereum (if you have ETH/USDC on mainnet)

Bridge USDC:
- Go to https://portal.polygon.technology/bridge
- Connect MetaMask
- Select: Ethereum → Polygon PoS
- Bridge USDC (it will become USDC.e on Polygon)
- Wait 7-8 minutes for confirmation
Get MATIC for gas:
- Option 1: Free faucet - https://faucet.polygon.technology/
- Option 2: Bridge a tiny amount of ETH and swap for MATIC

Option B: Buy on Exchange (Recommended - Fastest!)

Buy USDC on any exchange (Coinbase, Kraken, Binance)
Withdraw to Polygon network (very important!)
- Network: Polygon (NOT Ethereum!)
- Address: 0xb99107501d... (your MetaMask address)
- Token: USDC
Wait for withdrawal (usually 5-10 minutes)
It will arrive as USDC.e automatically

Option C: Swap Your Existing USDC → USDC.e

If you have the new native USDC (0x3c499c542c...) on Polygon:

In MetaMask, find your USDC
Click "Swap"
From: USDC → To: USDC.e
Execute swap (1:1 ratio, minimal fees)

2.1 Verify Your Balances

Save this as check_balance.py:

#!/usr/bin/env python3
from web3 import Web3

# Connect to Polygon
w3 = Web3(Web3.HTTPProvider("https://polygon-rpc.com"))
print("✅ Connected to Polygon\n")

# Your wallet address
address = Web3.to_checksum_address("0xb99107501d...")

print(f"📍 Checking balances for: {address}\n")

# Check MATIC balance
matic_balance = w3.eth.get_balance(address)
matic_readable = w3.from_wei(matic_balance, 'ether')
print(f"💎 MATIC: {matic_readable} MATIC")

if float(matic_readable) < 0.01:
    print("   ⚠️  Low MATIC! Get some for gas fees.")
else:
    print("   ✅ Enough MATIC for gas")

# Check USDC.e balance (OLD USDC that Polymarket uses)
USDC_E = Web3.to_checksum_address("0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174")
abi = [{"constant":True,"inputs":[{"name":"","type":"address"}],"name":"balanceOf","outputs":[{"name":"","type":"uint256"}],"type":"function"}]

usdc = w3.eth.contract(address=USDC_E, abi=abi)
usdc_balance = usdc.functions.balanceOf(address).call()
usdc_readable = usdc_balance / 1e6  # USDC has 6 decimals
print(f"💵 USDC.e: {usdc_readable} USDC")

if usdc_readable < 1:
    print("   ⚠️  Low/no USDC.e! You need this to trade.")
else:
    print("   ✅ You have USDC.e for trading")

print("\n" + "="*50)
if float(matic_readable) >= 0.01 and usdc_readable >= 1:
    print("✅ Ready for next step! Run the allowance script.")
else:
    print("⚠️  Add funds before continuing.")
print("="*50)

Run it:

python check_balance.py

Expected output:

✅ Connected to Polygon
📍 Checking balances for: 0xb99107501d...
💎 MATIC: 0.15 MATIC
   ✅ Enough MATIC for gas
💵 USDC.e: 50.0 USDC
   ✅ You have USDC.e for trading
==================================================
✅ Ready for next step! Run the allowance script.
==================================================

Step 3: Set Token Allowances

Before trading, you must approve Polymarket's exchange contracts to spend your USDC.e. This is a one-time setup.

3.1 Install Dependencies

pip install web3 python-dotenv

3.2 Create Allowance Script

Save this as set_allowances.py:

#!/usr/bin/env python3
"""
Set token allowances for Polymarket trading.
This approves the exchange contracts to spend your USDC.e.
"""

import os
from web3 import Web3
from dotenv import load_dotenv

load_dotenv()

# Polygon RPC
POLYGON_RPC = os.getenv("POLYGON_RPC", "https://polygon-rpc.com")

# Contract addresses (checksummed)
USDC_E = Web3.to_checksum_address("0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174")
CTF_ADDRESS = Web3.to_checksum_address("0x4D97DCd97eC945f40cF65F87097ACe5EA0476045")
CTF_EXCHANGE = Web3.to_checksum_address("0x4bFb41d5B3570DeFd03C39a9A4D8dE6Bd8B8982E")
CTF_NEG_RISK = Web3.to_checksum_address("0xC5d563A36AE78145C45a50134d48A1215220f80a")

# Your private key
PRIVATE_KEY = os.getenv("POLY_PRIVATE_KEY")
if not PRIVATE_KEY:
    raise ValueError("POLY_PRIVATE_KEY not set in .env")

if PRIVATE_KEY.startswith("0x"):
    PRIVATE_KEY = PRIVATE_KEY[2:]

# Connect
w3 = Web3(Web3.HTTPProvider(POLYGON_RPC))
if not w3.is_connected():
    raise ConnectionError("Failed to connect to Polygon")

print(f"✅ Connected to Polygon (Chain ID: {w3.eth.chain_id})")

# Load account
account = w3.eth.account.from_key(PRIVATE_KEY)
print(f"🔑 Wallet: {account.address}")

# Check MATIC
matic = w3.eth.get_balance(account.address)
print(f"💰 MATIC: {w3.from_wei(matic, 'ether')} MATIC")

if matic < w3.to_wei(0.01, 'ether'):
    print("⚠️  Low MATIC! You need MATIC for gas.")

# ERC20 ABI
ERC20_ABI = [
    {"constant":False,"inputs":[{"name":"_spender","type":"address"},{"name":"_value","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"type":"function"},
    {"constant":True,"inputs":[{"name":"_owner","type":"address"},{"name":"_spender","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"type":"function"},
    {"constant":True,"inputs":[{"name":"_owner","type":"address"}],"name":"balanceOf","outputs":[{"name":"balance","type":"uint256"}],"type":"function"}
]

MAX_UINT256 = 2**256 - 1

def check_allowance(token_addr, spender_addr, name):
    token = w3.eth.contract(address=token_addr, abi=ERC20_ABI)
    allowance = token.functions.allowance(account.address, spender_addr).call()
    print(f"   Current {name} allowance: {allowance}")
    return allowance

def check_balance(token_addr, name, decimals=6):
    token = w3.eth.contract(address=token_addr, abi=ERC20_ABI)
    balance = token.functions.balanceOf(account.address).call()
    readable = balance / (10 ** decimals)
    print(f"   {name} balance: {readable}")
    return balance

def set_allowance(token_addr, spender_addr, name):
    token = w3.eth.contract(address=token_addr, abi=ERC20_ABI)
    nonce = w3.eth.get_transaction_count(account.address)
    
    txn = token.functions.approve(spender_addr, MAX_UINT256).build_transaction({
        'from': account.address,
        'nonce': nonce,
        'gas': 100000,
        'maxFeePerGas': w3.eth.gas_price * 2,
        'maxPriorityFeePerGas': w3.to_wei(30, 'gwei'),
        'chainId': 137
    })
    
    signed = account.sign_transaction(txn)
    print(f"   Sending approval for {name}...")
    tx_hash = w3.eth.send_raw_transaction(signed.raw_transaction)
    print(f"   TX: {tx_hash.hex()}")
    
    print(f"   Waiting for confirmation...")
    receipt = w3.eth.wait_for_transaction_receipt(tx_hash, timeout=120)
    
    if receipt['status'] == 1:
        print(f"   ✅ {name} approved!")
        return True
    else:
        print(f"   ❌ {name} approval failed!")
        return False

print("\n" + "="*60)
print("Polymarket Token Allowance Setup")
print("="*60 + "\n")

# Check USDC.e balance
print("📊 Checking balances...")
usdc_balance = check_balance(USDC_E, "USDC.e", decimals=6)

if usdc_balance == 0:
    print("⚠️  You have 0 USDC.e! Add funds first.")
    exit(1)

print("\n" + "-"*60)
print("Standard Exchange Allowances")
print("-"*60 + "\n")

# USDC.e for standard exchange
print("1️⃣  USDC.e → CTF Exchange...")
allowance = check_allowance(USDC_E, CTF_EXCHANGE, "USDC.e")
if allowance < MAX_UINT256 / 2:
    response = input("   Approve? (yes/no): ")
    if response.lower() in ['yes', 'y']:
        set_allowance(USDC_E, CTF_EXCHANGE, "USDC.e")
else:
    print("   ✅ Already approved!")

# CTF tokens (skip if you don't have any yet)
print("\n2️⃣  CTF → CTF Exchange...")
try:
    allowance = check_allowance(CTF_ADDRESS, CTF_EXCHANGE, "CTF")
    if allowance < MAX_UINT256 / 2:
        response = input("   Approve? (yes/no): ")
        if response.lower() in ['yes', 'y']:
            set_allowance(CTF_ADDRESS, CTF_EXCHANGE, "CTF")
    else:
        print("   ✅ Already approved!")
except:
    print("   ⚠️  No CTF tokens yet (normal for first time)")

print("\n" + "-"*60)
print("Neg-Risk Exchange Allowances")
print("-"*60 + "\n")

# USDC.e for neg-risk exchange
print("3️⃣  USDC.e → Neg-Risk Exchange...")
allowance = check_allowance(USDC_E, CTF_NEG_RISK, "USDC.e")
if allowance < MAX_UINT256 / 2:
    response = input("   Approve? (yes/no): ")
    if response.lower() in ['yes', 'y']:
        set_allowance(USDC_E, CTF_NEG_RISK, "USDC.e")
else:
    print("   ✅ Already approved!")

print("\n" + "="*60)
print("✅ Allowances complete!")
print("="*60)
print("\nYou can now trade on Polymarket! 🎉")

3.3 Run the Allowance Script

python set_allowances.py

You'll be prompted to approve each contract. Type yes and confirm the transactions in MetaMask (or they'll auto-confirm if using private key).

Expected output:

✅ Connected to Polygon (Chain ID: 137)
🔑 Wallet: 0xb99107501d...
💰 MATIC: 0.15 MATIC

============================================================
Polymarket Token Allowance Setup
============================================================

📊 Checking balances...
   USDC.e balance: 50.0

------------------------------------------------------------
Standard Exchange Allowances
------------------------------------------------------------

1️⃣  USDC.e → CTF Exchange...
   Current USDC.e allowance: 0
   Approve? (yes/no): yes
   Sending approval for USDC.e...
   TX: 0xabcd1234...
   Waiting for confirmation...
   ✅ USDC.e approved!

[... continues for other approvals ...]

============================================================
✅ Allowances complete!
============================================================

You can now trade on Polymarket! 🎉

Step 4: Generate API Credentials

Polymarket's API requires authenticated credentials tied to your wallet.

4.1 Install py-clob-client

# Create virtual environment (recommended)
python -m venv poly-env
source poly-env/bin/activate  # On Windows: poly-env\Scripts\activate

# Install client
pip install py-clob-client

4.2 Create Credential Generation Script

Save as get_poly_creds.py:

#!/usr/bin/env python3
"""
Generate Polymarket API credentials for your wallet.
"""

from py_clob_client.client import ClobClient
import json
import os
from dotenv import load_dotenv

load_dotenv()

# Your MetaMask private key (without 0x)
private_key = os.getenv("POLY_PRIVATE_KEY", "").replace("0x", "")

if not private_key:
    print("❌ POLY_PRIVATE_KEY not set in .env")
    exit(1)

print("🔗 Connecting to Polymarket CLOB...")

host = "https://clob.polymarket.com"
chain_id = 137

try:
    client = ClobClient(
        host=host,
        key=private_key,
        chain_id=chain_id,
    )
    
    print("✅ Connected!")
    print(f"📍 Your address: {client.get_address()}")
    
    print("\n🔑 Deriving API credentials...")
    creds = client.create_or_derive_api_creds()
    
    print("\n" + "="*60)
    print("SUCCESS! Your Polymarket API Credentials:")
    print("="*60)
    print(f"API Key:        {creds.api_key}")
    print(f"API Secret:     {creds.api_secret}")
    print(f"API Passphrase: {creds.api_passphrase}")
    print("="*60)
    
    # Save to file
    creds_data = {
        "apiKey": creds.api_key,
        "secret": creds.api_secret,
        "passphrase": creds.api_passphrase
    }
    
    with open("poly_api_creds.json", "w") as f:
        json.dump(creds_data, f, indent=2)
    
    print("\n✅ Credentials saved to: poly_api_creds.json")
    print("\n📝 Use these in your Rust code with PreparedCreds::from_api_creds()")
    
except Exception as e:
    print(f"\n❌ Error: {e}")
    print("\nTroubleshooting:")
    print("   - Make sure POLY_PRIVATE_KEY is correct")
    print("   - Wait a few minutes if you just connected MetaMask to polymarket.com")
    import traceback
    traceback.print_exc()

4.3 Generate Credentials

python get_poly_creds.py

Expected output:

🔗 Connecting to Polymarket CLOB...
✅ Connected!
📍 Your address: 0xb99107501d...

🔑 Deriving API credentials...

============================================================
SUCCESS! Your Polymarket API Credentials:
============================================================
API Key:        c1e38b3e-1f...
API Secret:     zdKjVch284...
API Passphrase: 9133fa637d...
============================================================

✅ Credentials saved to: poly_api_creds.json

Important: These credentials are tied to your wallet. Keep them secure! They bypass the signature step.

Step 5: Configure Your Trading Bot

5.1 Load API Credentials in Rust

In your main.rs:

use std::sync::Arc;
use polymarket_clob::{PolymarketAsyncClient, ApiCreds, PreparedCreds, SharedAsyncClient};

#[tokio::main]
async fn main() -> Result<()> {
    // Load environment
    dotenvy::dotenv().ok();
    let poly_private_key = std::env::var("POLY_PRIVATE_KEY")?;
    let poly_funder = std::env::var("POLY_FUNDER")?;
    
    // Create client
    let poly_client = PolymarketAsyncClient::new(
        "https://clob.polymarket.com",
        137,  // Polygon chain ID
        &poly_private_key,
        &poly_funder,
    )?;
    
    // Load API credentials from file
    let creds_json = std::fs::read_to_string("poly_api_creds.json")?;
    let api_creds: ApiCreds = serde_json::from_str(&creds_json)?;
    let prepared_creds = PreparedCreds::from_api_creds(&api_creds)?;
    
    // Create shared client for trading
    let poly_async = Arc::new(SharedAsyncClient::new(
        poly_client,
        prepared_creds,
        137
    ));
    
    // Start trading!
    info!("🚀 Ready to trade on Polymarket!");
    
    Ok(())
}

5.2 Set Signature Type for EOA

CRITICAL: In your order building code, set signature_type: 0 for EOA wallets:

let data = OrderData {
    maker: &self.inner.wallet_address_str,
    signer: &self.inner.wallet_address_str,
    signature_type: 0,  // ← 0 for EOA, 1 for smart contract wallets
    // ... other fields
};

Verification Scripts

Check Current Balance

python check_balance.py

Verify Allowances

from web3 import Web3

w3 = Web3(Web3.HTTPProvider("https://polygon-rpc.com"))
USDC_E = Web3.to_checksum_address("0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174")
CTF_EXCHANGE = Web3.to_checksum_address("0x4bFb41d5B3570DeFd03C39a9A4D8dE6Bd8B8982E")
YOUR_ADDRESS = Web3.to_checksum_address("0xb99107501d...")

abi = [{"constant":True,"inputs":[{"name":"_owner","type":"address"},{"name":"_spender","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"type":"function"}]

usdc = w3.eth.contract(address=USDC_E, abi=abi)
allowance = usdc.functions.allowance(YOUR_ADDRESS, CTF_EXCHANGE).call()

if allowance > 10**20:
    print("✅ Allowance is set (unlimited)")
else:
    print(f"⚠️  Allowance: {allowance} (should be very large)")

View Your Outcome Tokens

Check Polygonscan:

https://polygonscan.com/address/0xb99107501d...#tokentxnsErc1155

Or check on Polymarket:

https://polymarket.com → Connect MetaMask → Portfolio

Common Issues & Solutions

Issue: "invalid signature"

Cause: Wrong signature type or address mismatch

Solutions:

✅ Set signature_type: 0 (not 1) for EOA wallets
✅ Ensure maker and signer both use checksummed address
✅ Verify you're using the same private key that generated API credentials

Issue: "not enough balance / allowance"

Causes:

Wrong USDC token (need USDC.e, not native USDC)
Allowances not set
Multiple concurrent orders exhausting balance

Solutions:

✅ Swap to USDC.e (0x2791Bca...) if you have native USDC
✅ Run set_allowances.py again
✅ Reduce position sizes or add exposure limits

Issue: "Polymarket order failed 400: invalid amount for a marketable BUY order, min size: $1"

Cause: Polymarket requires minimum $1.00 order value

Solution:

// Before placing order
let order_value = (contracts as f64) * price;
if order_value < 1.0 {
    return Err(anyhow!("Order ${:.2} < $1.00 minimum", order_value));
}

Issue: Cloudflare 403 Forbidden

Cause: Bot-like request patterns

Solutions:

✅ Use better User-Agent headers (see Step 5.2)
✅ Add delays between requests
✅ Use a VPN if rate-limited

Issue: Can't see my trades in MetaMask

Explanation: Polymarket uses off-chain order matching. You won't see MetaMask transactions!

How to verify:

Check Polymarket portfolio: polymarket.com → Portfolio
Check ERC-1155 tokens on Polygonscan
Look for outcome tokens in your wallet

Reference

Key Addresses (Polygon Mainnet)

| Contract | Address | Purpose | |----------|---------|---------| | USDC.e (old) | 0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174 | Trading token | | CTF Exchange | 0x4bFb41d5B3570DeFd03C39a9A4D8dE6Bd8B8982E | Standard markets | | Neg-Risk Exchange | 0xC5d563A36AE78145C45a50134d48A1215220f80a | Neg-risk markets | | CTF Token | 0x4D97DCd97eC945f40cF65F87097ACe5EA0476045 | Outcome tokens |

Signature Types

| Type | Value | Use Case | |------|-------|----------| | EOA | 0 | MetaMask/hardware wallets | | POLY_PROXY | 1 | Polymarket smart contract wallets | | POLY_GNOSIS_SAFE | 2 | Gnosis Safe wallets |

Order Types

| Type | Description | |------|-------------| | GTC | Good-til-cancelled (stays open) | | FOK | Fill-or-kill (must fill completely) | | FAK | Fill-and-kill (fill what you can, cancel rest) | | GTD | Good-til-date (expires at time) |

Useful Links

Polymarket Docs: https://docs.polymarket.com
CLOB API: https://docs.polymarket.com/developers/CLOB
Polygon Bridge: https://portal.polygon.technology/bridge
Polygon Faucet: https://faucet.polygon.technology
Polygonscan: https://polygonscan.com

Security Best Practices

Never share your private key - Store in .env, add to .gitignore
Use a dedicated trading wallet - Don't use your main wallet
Start with small amounts - Test with $10-20 first

Polymarket CLOB API Trading Setup Guide

Polymarket CLOB API Trading Setup Guide

Table of Contents

Understanding the Architecture

Account Structure

Prerequisites

Required Tools

Required Tokens on Polygon

High-Level Overview

The Complete Flow

Step-by-Step Setup

Step 1: Get Your MetaMask Credentials

1.1 Get Your Wallet Address

1.2 Export Your Private Key

1.3 Create Your .env File

Step 2: Fund Your Polygon Wallet

Option A: Bridge from Ethereum (if you have ETH/USDC on mainnet)

Option B: Buy on Exchange (Recommended - Fastest!)

Option C: Swap Your Existing USDC → USDC.e

2.1 Verify Your Balances

Step 3: Set Token Allowances

3.1 Install Dependencies

3.2 Create Allowance Script

3.3 Run the Allowance Script

Step 4: Generate API Credentials

4.1 Install py-clob-client

4.2 Create Credential Generation Script

4.3 Generate Credentials

Step 5: Configure Your Trading Bot

5.1 Load API Credentials in Rust

5.2 Set Signature Type for EOA

Verification Scripts

Check Current Balance

Verify Allowances

View Your Outcome Tokens

Common Issues & Solutions

Issue: "invalid signature"

Issue: "not enough balance / allowance"

Issue: "Polymarket order failed 400: invalid amount for a marketable BUY order, min size: $1"

Issue: Cloudflare 403 Forbidden

Issue: Can't see my trades in MetaMask

Reference

Key Addresses (Polygon Mainnet)

Signature Types

Order Types

Useful Links

Security Best Practices

1.3 Create Your `.env` File