Polymarket.Net is a client library for accessing the Polymarket REST and Websocket API.

• Response data is mapped to descriptive models
• Input parameters and response values are mapped to discriptive enum values where possible
• High performance
• Automatic websocket (re)connection management
• Client side rate limiting
• Client side order book implementation
• Support for managing different accounts
• Extensive logging
• Support for different environments
• Easy integration with other exchange clients based on the CryptoExchange.Net base library
• Native AOT support

The library is targeting both .NET Standard 2.0 and .NET Standard 2.1 for optimal compatibility, as well as the latest dotnet versions to use the latest framework features.

dotnet add package Polymarket.Net

Polymarket.Net is available on GitHub packages. You'll need to add https://nuget.pkg.github.com/JKorf/index.json as a NuGet package source.

The NuGet package files are added along side the source with the latest GitHub release which can found here.

Basic request:

// Get the order book info for the outcomes of the first market via rest request
var markets = await polymarketRestClient.GammaApi.GetMarketsAsync(closed: false);
if (!markets.Success)
{
	Console.WriteLine("Failed: " + markets.Error);
	return;
}

var firstMarket = markets.Data[0];
var bookInfo = await polymarketRestClient.ClobApi.ExchangeData.GetOrderBooksAsync(firstMarket.ClobTokenIds!);

Place order:

var restClient = new PolymarketRestClient(opts => {
	opts.ApiCredentials = new PolymarketCredentials(new PolymarketL1Credential(
        SignType.Poly1271,
        "PRIVATEKEY",
        "DEPOSITADDRESS"
        ));
});

// Update the client with layer 2 credentials
var credentials = await polymarketRestClient.ClobApi.Account.GetOrCreateApiCredentialsAsync();
polymarketRestClient.UpdateL2Credentials(credentials.Data);

// Place Limit order to buy 50 shares at 0.1 ($10)
var tokenIdTest = "67565972075898091709163371829761231762318232475740950317083391526954889294846";
var result = await polymarketRestClient.ClobApi.Trading.PlaceOrderAsync(
    tokenIdTest, 
	OrderSide.Buy,
	OrderType.Limit, 
	50, 
	price: 0.1m);

WebSocket subscription:

// Subscribe to updates for a specific token/asset via the websocket API
var socketClient = new PolymarketSocketClient();
var tokenId = "11862165566757345985240476164489718219056735011698825377388402888080786399275";
var subscriptionResult = await polymarketSocketClient.ClobApi.SubscribeToTokenUpdatesAsync([tokenId2],
	priceUpdate =>
	{
		// Handle price change update
	},
	bookUpdate =>
	{
		// Handle order book update
	},
	lastTradePriceUpdate =>
	{
		// Handle last trade price update
	},
	tickSizeUpdate =>
	{
		// Handle tick size update
	},
	bestBidAskUpdate =>
	{
		// Handle best bid/ask change update
	});

Authenticate using Poly1271 signing and a deposit address, providing the private key and the deposit address. This should be used for Polymarket accounts created after 04 May 2026. This will require you to request the layer 2 credentials before orders can be placed:

var credsPoly1271Layer1 = new PolymarketCredentials(
	new PolymarketL1Credential(
		SignType.Poly1271, // Poly1271 signing, for accounts created after 4 May 2026
		"0x00..", // The private key for the wallet
		"0x00..")); // The polymarket deposit address, can be found in the web interface under `Profile -> Copy Address`

Authenticate using Poly1271 signing and a deposit address, providing the private key and the deposit address, while also providing previously requested layer 2 credentials. Can be used to place orders directly:

var credsPoly1271WithLayer2 = new PolymarketCredentials(
    new PolymarketL1Credential(
		SignType.Poly1271, // Poly1271 signing, for accounts created after 4 May 2026
		"0x00..", // The private key for the wallet
		"0x00..")); // The polymarket deposit address, can be found in the web interface under `Profile -> Copy Address`
    new HMACPassCredential(
        "KEY",// The L2 API key as previously retrieved with `polymarketRestClient.ClobApi.Account.GetOrCreateApiCredentialsAsync()`
        "SEC", // The L2 API secret as previously retrieved with `polymarketRestClient.ClobApi.Account.GetOrCreateApiCredentialsAsync()`
        "PASS" // The L2 API passphrase as previously retrieved with `polymarketRestClient.ClobApi.Account.GetOrCreateApiCredentialsAsync()`
    ));

Authenticate using an email account and providing the exported private key and the funding address. This will require you to request the layer 2 credentials before orders can be placed:

var credsEmailLayer1 = new PolymarketCredentials(
	new PolymarketL1Credential(
		SignType.Email, // Email wallet, when creating a new wallet via the web interface
		"0x00..", // The private key, can be exported from the web interface
		"0x00..")); // The polymarket funding address, can be found in the web interface under `Profile -> Your Polymarket Wallet Address`

Authenticate using an email account and providing the exported private key and the funding address, while also providing previously requested layer 2 credentials. Can be used to place orders directly:

var credsEmailWithLayer2 = new PolymarketCredentials(
    new PolymarketL1Credential(
        SignType.Email,// Email wallet, when creating a new wallet via the web interface
        "0x00..",// The private key, can be exported from the web interface
        "0x00.."), // The polymarket funding address, can be found in the web interface under `Profile -> Your Polymarket Wallet Address`
    new HMACPassCredential(
        "KEY",// The L2 API key as previously retrieved with `polymarketRestClient.ClobApi.Account.GetOrCreateApiCredentialsAsync()`
        "SEC", // The L2 API secret as previously retrieved with `polymarketRestClient.ClobApi.Account.GetOrCreateApiCredentialsAsync()`
        "PASS" // The L2 API passphrase as previously retrieved with `polymarketRestClient.ClobApi.Account.GetOrCreateApiCredentialsAsync()`
    ));

Authenticate using an external account, for example MetaMask, and providing the private key. This will require you to request the layer 2 credentials before orders can be placed:

var credsEoaLayer1 = new PolymarketCredentials(
    new PolymarketL1Credential(
        SignType.EOA, // Externally Owned Account wallet, when using an existing wallet to connect to polymarket
        "0x00..")); // The private key for the wallet

Authenticate using an external account, for example MetaMask, and providing the private key, while also providing previously requested layer 2 credentials. Can be used to place orders directly:

var credsEoaWithLayer2 = new PolymarketCredentials(
    new PolymarketL1Credential(
        SignType.EOA, // Externally Owned Account wallet, when using an existing wallet to connect to polymarket
        "0x00.." // The private key for the wallet
    ),
    new HMACPassCredential(
        "KEY", // The L2 API key as previously retrieved with `polymarketRestClient.ClobApi.Account.GetOrCreateApiCredentialsAsync()`
        "SEC", // The L2 API secret as previously retrieved with `polymarketRestClient.ClobApi.Account.GetOrCreateApiCredentialsAsync()`
        "PASS" // The L2 API passphrase as previously retrieved with `polymarketRestClient.ClobApi.Account.GetOrCreateApiCredentialsAsync()`
    ));

Retrieve and set layer 2 credentials need for placing orders (required when L2 credentials not provided in the credentials):

var credentialResult = await polymarketRestClient.ClobApi.Account.GetOrCreateApiCredentialsAsync();
if (credentialResult.Success)
    polymarketRestClient.UpdateL2Credentials(credentialResult.Data);

Set the previously created credentials:

// Via constructor
var client = new PolymarketRestClient(options =>
{
    options.ApiCredentials = credentials;
});

// Via dependency injection
services.AddPolymarket(options =>
{
    options.ApiCredentials = credentials
});

For information on the clients, dependency injection, response processing and more see the documentation, or have a look at the examples here or here.

Polymarket.Net includes AI-oriented documentation and examples for code generation tools:

See cryptoexchange-skills-hub for installable skills.

NOTE
Polymarket.Net uses the Builder Code mechanism for Polymarket, which means that an additional 1bps / 0.01% fee is charged on top of orders placed with the library to fund development. This is entirely optional and can be disabled in the client options by setting BuilderCode to null in the REST client options.

Polymarket.Net is based on the CryptoExchange.Net base library. Other exchange API implementations based on the CryptoExchange.Net base library are available and follow the same logic.

CryptoExchange.Net also allows for easy access to different exchange API's.

Exchange	Repository	Nuget
Aster	JKorf/Aster.Net
Binance	JKorf/Binance.Net
BingX	JKorf/BingX.Net
Bitfinex	JKorf/Bitfinex.Net
Bitget	JKorf/Bitget.Net
BitMart	JKorf/BitMart.Net
BitMEX	JKorf/BitMEX.Net
Bitstamp	JKorf/Bitstamp.Net
BloFin	JKorf/BloFin.Net
Bybit	JKorf/Bybit.Net
Coinbase	JKorf/Coinbase.Net
CoinEx	JKorf/CoinEx.Net
CoinGecko	JKorf/CoinGecko.Net
CoinW	JKorf/CoinW.Net
Crypto.com	JKorf/CryptoCom.Net
DeepCoin	JKorf/DeepCoin.Net
Gate.io	JKorf/GateIo.Net
HTX	JKorf/HTX.Net
HyperLiquid	JKorf/HyperLiquid.Net
Kraken	JKorf/Kraken.Net
Kucoin	JKorf/Kucoin.Net
Lighter	JKorf/Lighter.Net
Mexc	JKorf/Mexc.Net
OKX	JKorf/OKX.Net
Pionex	JKorf/Pionex.Net
Toobit	JKorf/Toobit.Net
Upbit	JKorf/Upbit.Net
Weex	JKorf/Weex.Net
WhiteBit	JKorf/WhiteBit.Net
XT	JKorf/XT.Net

When using multiple of these API's the CryptoClients.Net package can be used which combines this and the other packages and allows easy access to all exchange API's.

A Discord server is available here. For discussion and/or questions around the CryptoExchange.Net and implementation libraries, feel free to join.

Any support is greatly appreciated.

Make a one time donation in a crypto currency of your choice. If you prefer to donate a currency not listed here please contact me.

Btc: bc1q277a5n54s2l2mzlu778ef7lpkwhjhyvghuv8qf
Eth: 0xcb1b63aCF9fef2755eBf4a0506250074496Ad5b7
USDT (TRX) TKigKeJPXZYyMVDgMyXxMf17MWYia92Rjd

Alternatively, sponsor me on Github using Github Sponsors.

• Version 4.2.1 - 23 Jul 2026

  • Added GameId to PolymarketEvent model
  • Added Unmatched, Delayed values to OrderStatus Enum

• Version 4.2.0 - 21 Jul 2026

  • Updated CryptoExchange.Net to v12.2.0

• Version 4.1.2 - 13 Jul 2026

  • Added restClient.ClobApi.ExchangeData.GetPriceHistoriesAsync endpoint

• Version 4.1.1 - 11 Jul 2026

  • Updated CryptoExchange.Net to version 12.1.1 to fix deserialization issue for certain timestamps
  • Fixed GetOrderBookAsync deserialization if there is no trade price

• Version 4.1.0 - 09 Jul 2026

  • Updated CryptoExchange.Net to v12.1.0
  • Added 0.005 and 0.0025 tick size support
  • Added LastPrice to PolymarketOrderBook model
  • Fixed Gamma API timestamp parameter serialization
  • Fixed PolymarketNegRisk deserialization

• Version 4.0.0 - 29 Jun 2026

  • Result types:
    • (Web)CallResult types are replaced by HttpResult and WebSocketResult with the same logic
    • WebSocketResult now return additional info for websocket operations
    • Updated result types to record type
    • Removed implicit result type conversion to bool, if (result) no longer works, instead use if (result.Success)
    • Fixed result object nullability hinting, for example Data might be null if Success isn't checked for true
  • Clients:
    • Added ToString overrides on base API types
    • Added Exchange property on BaseApiClient
    • Added ApiCredentials property on Api clients
    • Updated ILogger source from client name to topic specific client name
    • Removed logging from client creation
    • Fixed issue in SocketApiClient.GetSocketConnection causing requests to always wait the full max 10 seconds when there was a reconnecting socket
  • Added bypass of order book request for place order if possible
  • Added SupportedEnvironments property to PlatformInfo
  • Added setter to PolymarketPlatform.RateLimiter to allow custom rate limit settings
  • Various small performance improvements
  • Fixed websocket connection attempts counting towards rate limit even when server could not be reached