Installation

Supported EVM Chains

Mainnets

• Mainnet (1)

• Optimism (10)

• Gnosis (100)

• Polygon (137)

• Base (8453)

• Arbitrum One (42161)

Testnets

• Arbitrum Goerli (421613)

• Goerli (5)

• BaseGoerli (84531)

• Mumbai (80001)

• Optimism Goerli (420)

• Scroll Alpha Testnet (534353) [deprecated]

• Sepolia (11155111)

Get your appId - (30 secs)

Before anything, go to the Sismo Factory and create your app. Once your app is created, make sure to get your appId.

Quick start - (1 min)

Chose and install the starter of your choice in one unique command line.

npx create-sismo-connect-app@latest
# or
npm create sismo-connect-app@latest
# or
yarn create sismo-connect-app

This command enables to you install one of the available starters:

1. offchain: Sismo Connect + Next.js request ZK Proofs from users and verify them in a backend

2. onchain: Sismo Connect + Next.js + Foundry + wagmi request ZK Proofs from users and verify them in a smart contract

3. [Upcoming] onchain: Sismo Connect + Next.js + hardhat + ethers coming very soon, until then, head over the Manual Installation if you want to use Sismo Connect with hardhat

Feel free to check the Sismo Connect Cheatsheet, a great companion when developing an app using Sismo Connect.

We are here to support you on our builders telegram group

Manual Installation

This section is intended for developers who have prior experience with incorporating new tools into their existing repositories.

Integrate Sismo Connect in Your Front End

Make a Sismo Connect Request, users will be redirected to their Data Vault to generate a ZK proof and send your front end a Sismo Connect Response. This response, containing the ZK proof, will be verified on your back end/smart contract.

Check the Sismo Connect Cheatsheet to see examples of requests.

1. Install our React Library

yarn

yarn add @sismo-core/sismo-connect-react

npm

npm install @sismo-core/sismo-connect-react

@sismo-core/sismo-connect-client is also available for non-React front ends. (docs)

2. Use our React Button to make Sismo Connect Requests

// Next.js https://nextjs.org/docs/getting-started/installation
// in src/page.tsx 
"use client";

import {
  SismoConnectButton,
  AuthType,
  SismoConnectResponse,
  ClaimType,
} from "@sismo-core/sismo-connect-react";

export default function Home() {
  return (
    <SismoConnectButton
      config={{
        appId: "0xf4977993e52606cfd67b7a1cde717069", // replace with your appId
        vault: {
          // For development purposes insert the Data Sources that you want to impersonate here
          // Never use this in production
          impersonate: [
            // EVM
            "leo21.sismo.eth",
            "0xA4C94A6091545e40fc9c3E0982AEc8942E282F38",
            "0x1b9424ed517f7700e7368e34a9743295a225d889",
            "0x82fbed074f62386ed43bb816f748e8817bf46ff7",
            "0xc281bd4db5bf94f02a8525dca954db3895685700",
            // Github
            "github:leo21",
            // Twitter
            "twitter:leo21_eth",
            // Telegram
            "telegram:leo21",
          ],
        },
        // displayRawResponse: true,
      }}
      // request proof of Data Sources ownership (e.g EVM, GitHub, twitter or telegram)
      auths={[{ authType: AuthType.GITHUB }]}
      // request zk proof that Data Source are part of a group
      // (e.g NFT ownership, Dao Participation, GitHub commits)
      claims={[
        // ENS DAO Voters
        { groupId: "0x85c7ee90829de70d0d51f52336ea4722" }, 
        // Gitcoin passport with at least a score of 15
        { groupId: "0x1cde61966decb8600dfd0749bd371f12", value: 15, claimType: ClaimType.GTE }
      ]} 
      // request message signature from users.
      signature={{ message: "I vote Yes to Privacy" }}
      // retrieve the Sismo Connect Reponse from the user's Sismo data vault
      onResponse={async (response: SismoConnectResponse) => {
        const res = await fetch("/api/verify", {
          method: "POST",
          body: JSON.stringify(response),
        });
        console.log(await res.json());
      }}
      // reponse in bytes to call a contract
      // onResponseBytes={async (response: string) => {
      //   console.log(response);
      // }}
    />
  );
}

Check the Sismo Connect Cheatsheet to get a large set of interesting requests.

Learn more about Sismo Connect config and impersonation mode.

Sismo Connect in Your Smart Contracts/Back Ends

Your back end/smart contract will receive a Sismo Connect Response forwarded from your front end that you must verify.

1. Install the Sismo Connect Library

Onchain - Verify in a Smart Contract

Foundry (recommended)

Make sure to have Foundry installed.

Install the Forge dependency:

foundryup
forge install sismo-core/sismo-connect-solidity --no-commit

Add the remapping in remappings.txt:

echo $'sismo-connect-solidity/=lib/sismo-connect-solidity/src/' >> remappings.txt

Hardhat

# install the package
yarn add @sismo-core/sismo-connect-solidity

Import the library

In your Solidity file:

import "@sismo-core/sismo-connect-solidity/contracts/SismoConnectLib.sol";

Offchain - Verify in a Back End

Install the TypeScript library

yarn

yarn add @sismo-core/sismo-connect-server

2. verify Sismo Connect responses sent from your front end

The Sismo Connect configuration and request used in your smart contract/backend must exactly match those from your frontend.

Onchain - Verify in a Smart Contract

// in src/Airdrop.sol of a Foundry project - https://book.getfoundry.sh/getting-started/first-steps
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "sismo-connect-solidity/SismoConnectLib.sol";

// This is a sample contract that shows how to use the SismoConnect library
contract Airdrop is SismoConnect {
    event ResponseVerified(SismoConnectVerifiedResult result);

    constructor()
        SismoConnect(
            buildConfig({
                // replace with your appId from the Sismo factory https://factory.sismo.io/
                // should match the appId used to generate the response in your frontend
                appId: 0xf4977993e52606cfd67b7a1cde717069,
                // For development purposes insert when using proofs that contains impersonation
                // Never use this in production
                isImpersonationMode: true
            })
        )
    {}

    function verifySismoConnectResponse(bytes memory response) public {
        // build the auth and claim requests that should match the response
        AuthRequest[] memory auths = new AuthRequest[](1);
        auths[0] = buildAuth({authType: AuthType.GITHUB});

        ClaimRequest[] memory claims = new ClaimRequest[](2);
        // ENS DAO Voters
        claims[0] = buildClaim({groupId: 0x85c7ee90829de70d0d51f52336ea4722});
        // Gitcoin passport with at least a score of 15
        claims[1] = buildClaim({
            groupId: 0x1cde61966decb8600dfd0749bd371f12,
            value: 15,
            claimType: ClaimType.GTE
        });

        // verify the response regarding our original request
        SismoConnectVerifiedResult memory result = verify({
            responseBytes: response,
            auths: auths,
            claims: claims,
            signature: buildSignature({message: "I vote Yes to Privacy"})
        });

        emit ResponseVerified(result);
    }
}

Offchain - Verify in a Back End

Create an API route to receive the Sismo Connect response and verify it.

// Next.js API route support: https://nextjs.org/docs/api-routes/introduction
// in src/app/api/verify/route.ts

import {
  AuthType,
  ClaimType,
  SismoConnect,
  SismoConnectVerifiedResult,
} from "@sismo-core/sismo-connect-server";
import { NextResponse } from "next/server";

const sismoConnect = SismoConnect({
  config: {
    appId: "0xf4977993e52606cfd67b7a1cde717069",
    vault: {
      // For development purposes insert the Data Sources that you want to impersonate here
      // Never use this in production
      impersonate: [
        // EVM
        "leo21.sismo.eth",
        "0xa4c94a6091545e40fc9c3e0982aec8942e282f38",
        // Github
        "github:leo21",
        // Twitter
        "twitter:leo21_eth",
        // Telegram
        "telegram:leo21",
      ],
    },
  },
});

// this is the API route that is called by the SismoConnectButton
export async function POST(req: Request) {
  const sismoConnectResponse = await req.json();
  try {
    // verify the sismo connect response that corresponds to the request
    const result: SismoConnectVerifiedResult = await sismoConnect.verify(sismoConnectResponse, {
      auths: [{ authType: AuthType.GITHUB }],
      claims: [
        // ENS DAO Voters
        { groupId: "0x85c7ee90829de70d0d51f52336ea4722" }, 
        // Gitcoin passport with at least a score of 15
        { groupId: "0x1cde61966decb8600dfd0749bd371f12", value: 15, claimType: ClaimType.GTE },
      ],
      // verify signature from users.
      signature: { message: "I vote Yes to Privacy" },
    });
    return NextResponse.json(result, { status: 200 });
  } catch (e: any) {
    console.error(e);
    return NextResponse.json(e.message, { status: 500 });
  }
}

If you are using Nextjs, you will need to add this config in the next.config.js file to be able to verify the proof. You can find more information here.

/** @type {import('next').NextConfig} */
const nextConfig = {
  experimental: {
    serverComponentsExternalPackages: ["@sismo-core/sismo-connect-server"],
  },
}

module.exports = nextConfig