| name | lovable-ethereum-sepolia |
| description | Ship a Lovable app on Ethereum Sepolia — Privy Google/email sign-in with embedded wallet, native Privy gas sponsorship (no ZeroDev), Hardhat deploy + Etherscan verify, optional IPFS via Pinata. Use when the user asks for a Sepolia demo, testnet contract, sponsored-tx UX on Ethereum, or timestamp / provenance / mint flow on Sepolia. |
Lovable · Ethereum Sepolia
Everything needed to ship a working Sepolia demo: Google sign-in via Privy,
embedded wallet, native Privy gas sponsorship (no ZeroDev, no smart
wallets), one Solidity contract deployed + verified on Etherscan, optional
IPFS pin via Pinata. Chain id 11155111.
Non-obvious rules (get these wrong and it silently fails)
-
Sepolia does NOT need ZeroDev or smart wallets. Privy's native gas
sponsorship covers Sepolia. Enable it in the dashboard and pass
sponsor: true per call — that's it. Don't wire SmartWalletsProvider
or a paymaster URL.
-
Dashboard config (one-time, user). Privy dashboard → Gas
sponsorship → App pays → add chain Ethereum Sepolia → toggle
Allow transactions from the client ON. Native sponsorship requires
TEE execution, which is the current Privy default. Without any of
these, sendTransaction hangs or falls back to user-paid with a
non-zero fee.
-
Both fields on every call:
sendTransaction(
{ to, data, chainId: 11155111 },
{ address: embedded.address, sponsor: true }
);
Approval sheet still appears — fee reads US$0.00 — user taps
Approve once. There is no supported way to skip that sheet on the
embedded-EOA path.
-
Do NOT pass uiOptions: { showWalletUIs: false }. Privy aborts the
send with signal is aborted without reason. This is the #1 way to
waste an hour thinking sponsorship is broken. Just remove the field.
-
Wrap sendTransaction in a 45s Promise.race timeout whose reject
message names the exact dashboard toggles. Without it, a misconfigured
dashboard hangs the UI forever with no diagnosable error. Reference
shape in references/privy-sponsored-tx.md.
-
SSR-safe Privy mount is mandatory. lazy(() => import("./privy-client-entry"))
inside <ClientOnly> + <Suspense>. Never import
@privy-io/react-auth at module scope of a route file — SSR bundle
explodes. See evvm-privy-integration skill for the full mount pattern.
-
Pass chainId: 11155111 on every sendTransaction. Sponsorship
is configured per-chain in the dashboard; if you omit chainId the
embedded wallet may default to mainnet and the sponsor rule does not
match. You do NOT need defaultChain/supportedChains in the
PrivyProvider config — if you set them anyway, use viem's sepolia
object, never a { id, name } as never stub.
-
viem event reads on the free public RPC rate-limit past ~9000 blocks.
Cap getLogs ranges (fromBlock = head - 9000n) or wire an Alchemy
URL. For production reliability keep both:
import.meta.env.VITE_SEPOLIA_RPC_URL in the browser, SEPOLIA_RPC_URL
in Hardhat.
-
Contract deploys use a plain Node EOA, not sponsorship. Hardhat
reads METAMASK_PRIVATE_KEY + SEPOLIA_RPC_URL. Fund from
https://sepoliafaucet.com or Alchemy's faucet. Sponsorship only
covers user-triggered txs at runtime.
-
Etherscan v2 verification for Sepolia uses chainid=11155111 in the
URL query string, not the POST body. One ETHERSCAN_API_KEY covers
every chain via v2. Unlike Fuji (Snowtrace + Etherscan) there is no
second explorer to submit to. See
references/hardhat-etherscan-verify.md.
When to use
| User asks for… | Use this skill |
|---|
| A Sepolia demo / testnet dApp | Yes |
| Gas-sponsored UX on Ethereum L1 (no popup fee) | Yes |
| Timestamp / event-log / provenance contract on Sepolia | Yes |
| ERC-721 mint with IPFS-backed metadata on Sepolia | Yes (pair with references/pinata-ipfs.md) |
| Sepolia → L2 bridging / CCTP | No — see dance-ucp-arc-circle |
| Mainnet payments | No — use payments--enable_* |
| A different testnet (Base Sepolia, Fuji, Amoy, Robinhood, Tempo) | Use the matching chain-specific skill |
Required secrets
| Name | Purpose | When |
|---|
PRIVY_APP_ID (+ VITE_PRIVY_APP_ID) | Google/email login + embedded wallet | Always |
METAMASK_PRIVATE_KEY | Hardhat deployer EOA | Only if you deploy a contract |
SEPOLIA_RPC_URL (+ VITE_SEPOLIA_RPC_URL) | Alchemy HTTPS URL | Recommended; free public RPC works but rate-limits |
ETHERSCAN_API_KEY | Etherscan v2 verify | Only if you deploy a contract |
PINATA_JWT (+ VITE_PINATA_JWT) | IPFS pinning | Only if the app pins media/metadata |
Do NOT add any ZeroDev / bundler / paymaster keys — native Privy
sponsorship handles it.
Reference index
references/privy-sponsored-tx.md — canonical privy-client-entry.tsx
and privy-root.tsx, dashboard walkthrough, error tablereferences/hardhat-etherscan-verify.md — deploy script, verify CLI +
curl fallback, src/data/contract.json shapereferences/pinata-ipfs.md — browser upload, gateway URLs, ERC-721
metadata patternreferences/failure-modes.md — symptom → cause → fix table
Related skills
evvm-privy-integration — SSR-safe Privy mount pattern (deeper coverage of PrivyRoot + ClientOnly)robinhood-lovable — Hardhat + Blockscout verify + Pinata + smart-wallet path (use for Robinhood testnet, not Sepolia)lovable-avalanche-x402 — Etherscan v2 multi-verifier pattern (Fuji + Routescan)lovable-tempo — TIP-20 pay pattern for Tempo, similar Privy sponsorship shape
Canonical minimal src/data/contract.json
{
"address": "0x…",
"deployTx": "0x…",
"chainId": 11155111,
"network": "Sepolia",
"explorer": "https://sepolia.etherscan.io"
}
The UI reads contractCfg.address + contractCfg.chainId from this file
and links every tx via ${contractCfg.explorer}/tx/${hash}.
