SketchStream
Stream live sketches with integrated onchain tips and gasless wallet logins for artist-audience engagement.
Privy social + sponsored tx· wallet UX
Section · Onchain
full primer →The primitive.
Painters sign in with Google through Privy — no seed phrase, no MetaMask popup — and their live drawing streams actions are sent from an embedded wallet on BNB Smart Chain Testnet.
Why this primitivePrivy wallet and sponsored tx allow instant, gas-free microtransactions during live art streams.
Kernel
Privy embedded wallet bootstrapped with PRIVY_APP_ID — Google sign-in plus an auto-provisioned wallet on BNB Smart Chain Testnet
Drives the UI as
a one-click 'Sign in with Google' that drops the user straight into the app with an onchain identity
Required keys.
METAMASK_PRIVATE_KEY
Exported from MetaMask. Fund on BNB Smart Chain Testnet via the BNB faucet.
open ↗BSC_TESTNET_RPC_URL
BSC Testnet HTTPS RPC. Public: https://data-seed-prebsc-1-s1.bnbchain.org:8545 (or your own provider).
open ↗Add these in your Lovable project under Settings → Secrets before pasting the prompt below.
Appendix · Mega-prompt
The build prompt.
budget · 1 message
Paste into a fresh Lovable project. Make sure all five secrets above are set first. read the build strategy →
Build "SketchStream" in ONE Lovable message. Single-page demo.
CONCEPT
Stream live sketches with integrated onchain tips and gasless wallet logins for artist-audience engagement.
Discipline: Visual Art (live drawing streams).
Onchain primitive: Privy social + sponsored tx. Why this primitive: Privy wallet and sponsored tx allow instant, gas-free microtransactions during live art streams.
5-CREDIT BUDGET (HARD LIMIT):
- ONE single-page app. No router, no Lovable Cloud, no database, no auth flows beyond Privy drop-in.
- ONE Solidity contract, <=80 lines, deployed to BSC Testnet, verified on BscScan.
- Privy is the auth + embedded-wallet layer (Google login, wallet auto-provisioned).
- Gas is USER-PAID. There is NO sponsorship on BSC Testnet in this template — the user needs a small tBNB balance from the faucet. Surface a "Get tBNB" faucet link in the UI.
- Pinata/IPFS only if the idea genuinely needs to store a file or metadata.
- At most ONE AI call per user action (use Lovable AI Gateway with LOVABLE_API_KEY if AI is part of the idea).
- Skip tests, skip CI, skip docs pages. Ship the demo, nothing else.
STACK
- React + Vite single page (the index route).
- SSR-safe Privy mount is mandatory. Never import @privy-io/react-auth at
module scope of a route file — it crashes SSR. Use
lazy(() => import('./privy-client-entry')) inside <ClientOnly> + <Suspense>,
and put <PrivyProvider> only inside privy-client-entry.tsx.
- PrivyProvider config uses viem's `bscTestnet` chain (chainId 97):
import { bscTestnet } from 'viem/chains';
<PrivyProvider appId={import.meta.env.VITE_PRIVY_APP_ID}
config={{ loginMethods:['google','email'],
embeddedWallets:{ ethereum:{ createOnLogin:'users-without-wallets' } },
defaultChain: bscTestnet,
supportedChains: [bscTestnet],
appearance:{ theme:'dark' } }}>
- Read the embedded wallet from useWallets, not user.wallet:
const embedded = wallets.find(w => w.walletClientType === 'privy');
- Every send goes through Privy `useSendTransaction` with `chainId: 97` and
`address` (NO `sponsor` — BSC Testnet is user-paid in this template):
await sendTransaction(
{ to, data, chainId: 97 },
{ address: embedded.address }
);
- Do NOT pass uiOptions:{ showWalletUIs:false } — it aborts with
"signal is aborted without reason". The approval sheet is expected on
the embedded-EOA path; the user pays a tiny tBNB fee.
- Do NOT add ZeroDev / SmartWalletsProvider / a paymaster URL. This
template is intentionally user-paid on BSC Testnet.
- USER FUNDING: the embedded wallet needs a small tBNB balance. Show a
"Get tBNB" link next to the connect button pointing at
https://www.bnbchain.org/en/testnet-faucet. Catch "insufficient funds"
errors and re-surface the faucet link inline.
- Hardhat in /contracts (kept outside the Vite bundle). Install
`@nomicfoundation/hardhat-toolbox` AND `@nomicfoundation/hardhat-verify@latest`
(>=3.x — older versions still hit Etherscan v1 and fail with
"You are using a deprecated V1 endpoint, switch to Etherscan API V2").
- hardhat.config.cjs uses the Etherscan v2 single-key shape with a
customChains entry pointing v2 at BscScan (chainid=97):
require("@nomicfoundation/hardhat-toolbox");
require("@nomicfoundation/hardhat-verify");
module.exports = {
solidity: { version: "0.8.24", settings: { optimizer: { enabled: true, runs: 200 } } },
networks: { bscTestnet: {
url: process.env.BSC_TESTNET_RPC_URL || "https://data-seed-prebsc-1-s1.bnbchain.org:8545",
accounts: [process.env.METAMASK_PRIVATE_KEY.startsWith("0x")
? process.env.METAMASK_PRIVATE_KEY : "0x" + process.env.METAMASK_PRIVATE_KEY],
chainId: 97,
} },
etherscan: {
apiKey: process.env.BSCSCAN_API_KEY,
customChains: [{
network: "bscTestnet",
chainId: 97,
urls: {
apiURL: "https://api.etherscan.io/v2/api?chainid=97",
browserURL: "https://testnet.bscscan.com",
},
}],
},
sourcify: { enabled: false },
};
- Deploy: `npx hardhat run scripts/deploy.cjs --network bscTestnet`.
- Verify: `npx hardhat verify --network bscTestnet <address>` — verified source
appears at `https://testnet.bscscan.com/address/<address>#code`.
- Frontend reads: create a viem public client on bscTestnet using the same RPC —
`createPublicClient({ chain: bscTestnet, transport: http(import.meta.env.VITE_BSC_TESTNET_RPC_URL) })`.
Cap `getLogs` ranges to `fromBlock = head - 9000n`; the public RPC rate-limits wider windows.
- Write the deployed address to `src/data/contract.json` so the UI links to
`https://testnet.bscscan.com/address/<address>`.
CONTRACT (contracts/SketchStream.sol):
```solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;
/// @title SocialLogSketchStream
/// @notice Stream live sketches with integrated onchain tips and gasless wallet logins for artist-audience engagement.
/// @notice Built during the Creative AI & Quantum Hackathon organised by StreetKode Fam during Indian Krump Festival 14
contract SocialLogSketchStream {
event Logged(address indexed author, string cid, uint256 at);
/// @notice Built during the Creative AI & Quantum Hackathon organised by StreetKode Fam during Indian Krump Festival 14
function log(string calldata cid) external {
emit Logged(msg.sender, cid, block.timestamp);
}
}
```
USER FLOW
1. Land on page -> 'Sign in with Google' (Privy) -> embedded wallet auto-provisioned on BSC Testnet.
2. Prompt user to fund with tBNB (faucet link) if balance is zero.
3. Every live drawing streams action the user performs is sent as a BSC Testnet tx (`log(payload)`) via Privy's embedded wallet and displayed with a BscScan link. Show a small 'need tBNB?' faucet link the first time the user hits a low-balance error.
4. Footer renders: "Built during the Creative AI & Quantum Hackathon organised by StreetKode Fam during Indian Krump Festival 14"
REQUIRED SECRETS (Lovable -> Project Settings -> Secrets):
- METAMASK_PRIVATE_KEY BSC Testnet deployer key. Fund it with tBNB: https://www.bnbchain.org/en/testnet-faucet
- BSC_TESTNET_RPC_URL BSC Testnet HTTPS RPC. Public: https://data-seed-prebsc-1-s1.bnbchain.org:8545 (rate-limited).
Also expose as VITE_BSC_TESTNET_RPC_URL for the frontend viem client.
- BSCSCAN_API_KEY For `npx hardhat verify` via Etherscan v2 (chainid=97). Get: https://etherscan.io/myapikey
- PRIVY_APP_ID Google/email sign-in + embedded wallet. Docs: https://docs.privy.io/llms-full.txt
Also expose as VITE_PRIVY_APP_ID for the client.
- PINATA_JWT IPFS uploads (only if the app pins media). Docs: https://docs.pinata.cloud/llms-full.txt
Also expose as VITE_PINATA_JWT for the client.
CREDIT (must appear in UI footer AND as NatSpec on every deployed contract):
Built during the Creative AI & Quantum Hackathon organised by StreetKode Fam during Indian Krump Festival 14
Market sizing.
TAM
$1.5B
live streaming art markets
SAM
$400M
live tip-enabled drawing platforms
SOM
$25M
gasless tipping users
Indicative figures for hackathon pitches — refine with your own research before raising.
Adjacent entries.
collaborative painting
Canvas Collaborate
Enable painters to co-create artworks with seamless onchain identity and gasless contributions.
illustrator communityIllustrator Guild
Create a hosted network for illustrators to share, sell, and verify work with easy login and zero gas fees.
generative artGenerative Canvas
Let generative artists deploy and monetize code-driven art with instant gasless onboarding and transactions.
art provenance trackingGallery Ledger
Provide gallerists with gasless, onchain tools to prove artwork provenance and authenticity effortlessly.