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# Developer integration guide

Integrate pERC20 into wallets, dApps, and backend services.

## Integration checklist

* [ ] Connect to correct chain (`chainId` in proofs = pool chain)
* [ ] Implement note scanning (`NoteAdded` + trial-decrypt)
* [ ] Integrate prover (rapidsnark service or WASM)
* [ ] Encode `PrivacyCall` / `BundleAction` (see `bundleCodec.ts`)
* [ ] Handle mint/burn public amounts vs private transfers
* [ ] Optional: relayer for submitter privacy
* [ ] Optional: indexer for faster sync
* [ ] Do **not** assume ERC-20 ABI compatibility

## Key libraries

| Task                | Reference                                              |
| ------------------- | ------------------------------------------------------ |
| ABI encode/decode   | `apps/web/src/issuance/bundleCodec.ts`                 |
| EVM reads           | `apps/web/src/crypto/evmRead.ts`                       |
| Witness build       | `crates/privacybtc-witness/`                           |
| Groth16 prove       | `crates/privacybtc-groth16/`, `privacy-prover` service |
| Contract interfaces | `contracts/interfaces/IPERC20.sol`                     |

## Contract addresses

Query factory → pool mapping on your target chain. Test env addresses in [Performance benchmarks](/plabs-docs/ecosystem/performance.md).

## Testing

```bash
# Unit tests
forge test --match-contract PERC20Test

# Real-proof E2E
forge test --match-contract PERC20E2ETest

# Full stack
e2e/scripts/run_full_e2e.sh
```

## Common pitfalls

| Pitfall                    | Fix                                                |
| -------------------------- | -------------------------------------------------- |
| Wrong `chainId` in sighash | Use pool's chain, not wallet network               |
| Trusting `NoteAdded` alone | Recipient must trial-decrypt to confirm            |
| On-chain `approve`         | Use wallet ZIP-32 flow; no contract method         |
| `pubFields` mismatch       | Must equal top-level calldata fields               |
| Skipping `< Fr` checks     | Reference impl enforces; match in custom verifiers |

## *(expand)*

* REST API for prover-service
* Indexer query schema
* Mobile / hardware wallet considerations

## Next

* [Off-chain services](/plabs-docs/ecosystem/off-chain-services.md)
* [Universal call format](/plabs-docs/privacy-core/universal-call-format.md)
* [ERC-8302](/plabs-docs/privacy-core/perc20/eip-8302.md)


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