Polymarket.Net
May 12, 2026 · View on GitHub
Polymarket.Net is a client library for accessing the Polymarket REST and Websocket API.
Features
- 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
Supported Frameworks
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.
| .NET implementation | Version Support |
|---|---|
| .NET Core | 2.0 and higher |
| .NET Framework | 4.6.1 and higher |
| Mono | 5.4 and higher |
| Xamarin.iOS | 10.14 and higher |
| Xamarin.Android | 8.0 and higher |
| UWP | 10.0.16299 and higher |
| Unity | 2018.1 and higher |
Install the library
NuGet
dotnet add package Polymarket.Net
GitHub packages
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.
Download release
The NuGet package files are added along side the source with the latest GitHub release which can found here.
How to use
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
});
Authentication
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.
AI / LLM documentation
Polymarket.Net includes AI-oriented documentation and examples for code generation tools:
| File | Purpose |
|---|---|
AGENTS.md | Assistant skill with core Polymarket.Net patterns, pitfalls, and examples |
CLAUDE.md | Claude-oriented guide with authentication rules and source-of-truth files |
llms.txt | Short LLM index with links to docs, examples, and critical usage rules |
llms-full.txt | Detailed LLM context with endpoint routing, authentication levels, code patterns, and anti-hallucination checks |
docs/ai-api-map.md | Table-style intent-to-method map for CLOB, Gamma, Data, WebSocket, authentication, DI, and local order book workflows |
Examples/ai-friendly | Compilable single-file examples for common REST, authentication/trading, WebSocket, DI/order book, and error handling workflows |
GitHub Copilot and Cursor instructions are also provided in .github/copilot-instructions.md and .cursor/rules/polymarket-net.mdc; both point back to the root AI context files.
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.
CryptoExchange.Net
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 |  |
| Mexc | JKorf/Mexc.Net |  |
| OKX | JKorf/OKX.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.
Discord
A Discord server is available here. For discussion and/or questions around the CryptoExchange.Net and implementation libraries, feel free to join.
Supported functionality
REST API
| API | Supported | Location |
|---|---|---|
| Events | ✓ | restClient.ClobApi.ExchangeData |
| Markets | ✓ | restClient.ClobApi.ExchangeData |
| Orderbook & Pricing | ✓ | restClient.ClobApi.ExchangeData |
| Orders | ✓ | restClient.ClobApi.Trading / restClient.ClobApi.Account |
| Trades | ✓ | restClient.ClobApi.Trading / restClient.ClobApi.Account |
| CLOB Markets | ✓ | restClient.ClobApi.ExchangeData |
| Rebates | X | |
| Rewards | X | |
| Profile | partial | restClient.DataApi |
| Leaderboard | X | |
| Builders | X | |
| Search | ✓ | restClient.GammaApi |
| Tags | ✓ | restClient.GammaApi |
| Series | ✓ | restClient.GammaApi |
| Comments | X | |
| Sports | ✓ | restClient.GammaApi |
| Bridge | X | |
| Relayer | X |
WebSocketocket API
| API | Supported | Location |
|---|---|---|
| Market Channel | ✓ | socketClient.ClobApi |
| User Channel | ✓ | socketClient.ClobApi |
| Sport Channel | ✓ | socketClient.ClobApi |
Support the project
Any support is greatly appreciated.
Donate
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
Sponsor
Alternatively, sponsor me on Github using Github Sponsors.
Release notes
-
Version 3.1.0 - 09 May 2026
- Added support for Poly1271 signing
-
Version 3.0.3 - 01 May 2026
- Fixed incorrect makerAddress parameter serialization in GetUserTradesAsync
-
Version 3.0.2 - 01 May 2026
- Improved order placement performance
- Fixed side parameter missing in PlaceMultipleOrdersAsync endpoint
- Fixed PlaceMultipleOrdersAsync not sending side parameter
- Fixed CancelOrdersOnMarketAsync incorrect endpoint
- Fixed restClient.ClobApi.Account.GetBuilderTradesAsync endpoint
-
Version 3.0.1 - 29 Apr 2026
- Removed FeeRateBps from PolymarketOrderBase model fixing deserialization exception in websocket user updates
-
Version 3.0.0 - 28 Apr 2026
-
Updated library to use V2 Clob API
-
Updated CryptoExchange.Net to version 11.1.1
-
Added restClient.ClobApi.ExchangeData.GetMarketInfoAsync endpoint
-
Added tokenId parameter to GetUserTradesAsync endpoint
-
Added BuilderCode to REST client options
-
Updated GetUserTradesAsync endpoint from /data/trades to /trades
-
Updated PostOrderHeartbeatAsync endpoint from /v1/heartbeats to /heartbeats
-
Updated documentation references
-
Renamed all ConditionId parameters/properties to MarketId for consistency
-
Renamed all AssetId parameters/properties to TokenId for consistency
-
Removed deprecated takerAddress, nonce and feeRateBps from PlaceOrder endpoints
-
Removed takerAddress parameter from GetUserTradesAsync endpoint
-
Removed BuilderApiKey, BuilderSecret, BuilderPass from REST client options
-
Notes for updating:
- This release only supports request signing for the V2 Clob API, which will go live after the 28th of April 2026 11:00 UTC. To test this release before the V2 API is live update the CLOB rest address to
https://clob-v2.polymarket.comin the client options Environment setting - A default builder fee of 0.01% / 1bps has been enabled by default to support development, this can be turned of in the client options by setting BuilderCode to null
- This release only supports request signing for the V2 Clob API, which will go live after the 28th of April 2026 11:00 UTC. To test this release before the V2 API is live update the CLOB rest address to
-
-
Version 2.2.0 - 24 Apr 2026
- Added QuantityType parameter to PlaceOrder endpoints which allows to specify market buy orders in USD value instead of number of shares
- Updated book caching logic to only store for 2 seconds instead of indefinitely to fix outdated info preventing correct order placement
- Fixed PolymarketTrade Role mapping
-
Version 2.1.1 - 13 Apr 2026
- Default timeInForce to ImmediateOrCancel for market orders if parameter not provided
- Fixed order quantity rounding issues
-
Version 2.1.0 - 09 Apr 2026
- Updated CryptoExchange.Net to version 11.1.0, see https://github.com/JKorf/CryptoExchange.Net/releases/ for full release notes
- Added Polymarket Data API support
- Improved socketClient.ClobApi.SubscribeToTokenUpdatesAsync registration logic
- Fixed parameters not getting send with various requests
- Fixed startTimeMin, startTimeMax parameter serialization on GammaApi GetMarketsAsync and GetEventsAsync
-
Version 2.0.0 - 24 Mar 2026
-
Updated CryptoExchange.Net to version 11.0.1, see https://github.com/JKorf/CryptoExchange.Net/releases/ for full release notes
-
Updated class for supplying API credentials from ApiCredentials to PolymarketCredentials
-
Updated Shared order status parsing to default to Unknown value if not parsable
-
Updated signing logic to unified logic in the CryptoExchange.Net library
-
Added cursor parameter to restClient.ClobApi.Trading.GetOpenOrdersAsync endpoint
-
Updated PolymarketEvent ParentEvent to ParentEventId and changed type to long?
-
Fixed SubscribeToPlatformUpdatesAsync onMarketResolved handling
-
Fixed exception in PolymarketSocketClient.UpdateL2Credentials
-
Fixed parameter serialization restClient.ClobApi.Account.GetBuilderTradesAsync endpoint
-
Fixed parameter serialization restClient.ClobApi.Trading.GetOpenOrdersAsync endpoint
-
Notes for updating:
- Update ApiCredentials to PolymarketCredentials for authentication, and provided L1 and L2 credentials separately, i.e.
ApiCredentials = new ApiCredentials(signType, l1key, l1fundkey, l2key, l2sec, l2pass)=>ApiCredentials = new PolymarketCredentials(new PolymarketL1Credential(signType, l1key, l1fundkey), new HMACPassCredential(l2key, l2sec, l2pass))
- Update ApiCredentials to PolymarketCredentials for authentication, and provided L1 and L2 credentials separately, i.e.
-
-
Version 1.5.2 - 10 Mar 2026
- Updated order quantity/price rounding
- Updated xml comments to include json fields
-
Version 1.5.1 - 06 Mar 2026
- Fixed bug in market order buy price determination
- Fixed exception in PlaceOrderAsync when placing a market order when order book is empty
- Fixed incorrect parameter serialization in restClient.ClobApi.Trading.GetUserTradesAsync endpoint
- Fixed order expiration serialization in PlaceOrder endpoints
- Fixed conditionIds not getting sent in restClient.GammaApi.GetMarketsAsync endpoint
-
Version 1.5.0 - 06 Mar 2026
- Updated CryptoExchange.Net to version 10.8.0, see https://github.com/JKorf/CryptoExchange.Net/releases/ for full release notes
- Improved method XML comments
-
Version 1.4.1 - 26 Feb 2026
- Updated LastTradePrice on PolymarketBookUpdate model to nullable
-
Version 1.4.0 - 24 Feb 2026
- Updated CryptoExchange.Net to version 10.7.0
- Added restClient.ClobApi.Trading.PostOrderHeartbeatAsync endpoint
- Added websocket ping message sending
- Added additional Http settings to client options
- Updated Shared REST interfaces pagination logic
- Updated HttpClient registration, fixing issue of DNS changes not getting processed
- Fixed UserClientProvider using unconfigured HttpClient
-
Version 1.3.1 - 17 Feb 2026
- Updated CryptoExchange.Net to version 10.6.2, see https://github.com/JKorf/CryptoExchange.Net/releases/ for full release notes
- Fixed not correctly handling book snapshot websocket update
-
Version 1.3.0 - 16 Feb 2026
- Updated CryptoExchange.Net to version 10.6.0, see https://github.com/JKorf/CryptoExchange.Net/releases/ for full release notes
- Fixed SymbolOrderBook websocket subscription not getting closed if when waiting for initial data times out
-
Version 1.2.0 - 10 Feb 2026
- Updated CryptoExchange.Net to version 10.5.1, see https://github.com/JKorf/CryptoExchange.Net/releases/ for full release notes
- Updated UserClientProvider internal client cache to non-static to prevent cleanup issues
- Fixed websocket token subscription price change topic mapping
-
Version 1.1.0 - 06 Feb 2026
- Updated CryptoExchange.Net to version 10.4.0, see https://github.com/JKorf/CryptoExchange.Net/releases/ for full release notes
- Added OrderStatus.Matched value
- Fixed disposed clients getting returned from UserClientProvider
-
Version 1.0.1 - 27 Jan 2026
- Fixed signing issue certain token values
- Fixed rounding issue in quantity calculation
-
Version 1.0.0 - 22 Jan 2026
- Initial release