SDK Overview

2.1 Installation

npm install @zkgate/sdk
# or
yarn add @zkgate/sdk
# or
pnpm add @zkgate/sdk

---

2.2 Initialization

The SDK needs to know:

• which environment you are using (testnet / mainnet)

• your projectId / poolId (assigned during onboarding)

• optional relayer endpoint if you don’t want users to pay gas on-chain.

import { ZKGateClient } from "@zkgate/sdk";

const zkClient = new ZKGateClient({
  projectId: "my-project-001",
  poolId: "pool-DEX-001",
  env: "testnet", // "mainnet" when live
  relayerUrl: "https://relayer.zkgate.io", // optional
});

---

2.3 Core Concepts in the SDK

• commitment – a private representation of a user’s balance / position.

• nullifier – prevents double-spend of commitments.

• note – user-friendly wrapper around commitments (similar to UTXO).

• proof – zero-knowledge proof generated client-side or via prover service.

The SDK abstracts most of these away. In many cases you just call:

• deposit()

• executePrivate()

• withdraw()

---

2.4 Common Flows

2.4.1 Private Deposit Flow

User sends assets into the ZK Pool and receives a private note.

await zkClient.deposit({
  asset: "USDC",
  amount: "1000",
  fromAddress: userPublicAddress, // EVM, Solana, etc.
  chainId: 8453, // example
});

Under the hood, the SDK will:

1. Call the bridge contract on the origin chain.

2. Wait for confirmation.

3. Generate a commitment and send it to the ZKGate API.

4. Receive a note or local record representing the private balance.

---

2.4.2 Executing a Private Action (generic)

All private operations (swap, transfer, stake, lend, vote, etc.) go through a unified interface:

await zkClient.executePrivate({
  action: "swap",
  poolId: "pool-DEX-001",
  payload: {
    fromAsset: "USDC",
    toAsset: "ZK",
    amountIn: "500",
    minAmountOut: "490",
  },
});

The SDK will:

1. Select appropriate notes/commitments.

2. Build a witness for the circuit.

3. Generate a ZK proof (in browser or via remote prover).

4. Submit the proof + encrypted payload to the ZKGate sequencer.

---

2.4.3 Private Withdraw Flow

User wants to exit the private pool to a public chain address:

await zkClient.withdraw({
  asset: "USDC",
  amount: "300",
  destinationAddress: "0xUserPublicWallet",
  chainId: 8453,
});

The SDK will:

1. Build a ZK proof showing:

   • the user owns enough private balance

   • the note has not been spent before.

2. Submit withdraw request to the ZKGate L2.

3. Once finalized, trigger the bridge contract to send funds to the destination.

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2.5 Error Handling & Events

The SDK exposes events / hooks to help you build UX:

zkClient.on("proofGenerated", (info) => {
  console.log("Proof generated:", info);
});

zkClient.on("batchSubmitted", (info) => {
  console.log("Batch submitted:", info.batchId);
});

zkClient.on("finalized", (info) => {
  console.log("Finalized on L1:", info.txHash);
});

You can use these events to show loading states, progress indicators, or “finalized” badges in your dApp.