# Chain 2138 – Wallet & SDK Config (Defi Oracle Meta Testnet)

**Last Updated:** 2026-03-27  
**Document Version:** 1.0  
**Status:** Active Documentation

---

**Purpose:** Wallet and SDK settings for **Defi Oracle Meta Testnet** (chain ID **2138**).  
**RPC (public, chainlist):** `https://rpc.public-2138.defi-oracle.io`  
**WS (chainlist):** `wss://rpc.public-2138.defi-oracle.io`  
**Explorer (chainlist):** `https://public-2138.defi-oracle.io`  
**Chain ID:** 2138 (`0x85a`)  
**CAIP-2:** `eip155:2138`

Use LAN or staging RPC in place of the public URLs when testing privately.

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## 1. MetaMask (custom network)

| Field | Value |
|-------|--------|
| **Network name** | Defi Oracle Meta Testnet |
| **RPC URL** | `https://rpc.public-2138.defi-oracle.io` (or your node) |
| **Chain ID** | `2138` |
| **Currency symbol** | tETH |
| **Block explorer** | `https://public-2138.defi-oracle.io` |

**JSON** (programmatic add): `docs/04-configuration/metamask/METAMASK_NETWORK_CONFIG_2138.json`.

---

## 2. ethers.js (v6 example)

```javascript
const chain2138Testnet = {
  chainId: 2138,
  name: "Defi Oracle Meta Testnet",
  nativeCurrency: { name: "testEther", symbol: "tETH", decimals: 18 },
  rpcUrls: {
    default: { http: ["https://rpc.public-2138.defi-oracle.io"] },
  },
  blockExplorers: {
    default: { name: "Quorum Explorer", url: "https://public-2138.defi-oracle.io" },
  },
};

import { JsonRpcProvider } from "ethers";
const provider = new JsonRpcProvider("https://rpc.public-2138.defi-oracle.io");
const chainId = await provider.getNetwork().then((n) => Number(n.chainId)); // 2138
```

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## 3. Frontend DApp (Vite)

- Enable the chain in Wagmi: `VITE_ENABLE_CHAIN2138=true` or `1`  
- Optional overrides: `VITE_RPC_URL_2138`, `VITE_EXPLORER_URL_2138`  
- Trustless bridge L2 side: `VITE_TRUSTLESS_L2_CHAIN_ID=2138` plus lockbox/token env vars (see `smom-dbis-138/frontend-dapp/.env.example`)

---

## 4. Quick verification

```bash
curl -s -X POST https://rpc.public-2138.defi-oracle.io -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}'
# Expected: result "0x85a"
```

---

## 5. References

- **Testnet runbook**: `docs/testnet/DEFI_ORACLE_META_TESTNET_2138_RUNBOOK.md`
- **Mainnet (138) wallet doc**: `docs/04-configuration/CHAIN138_WALLET_CONFIG_VALIDATION.md`
- **Chain list (this repo)**: `pr-workspace/chains/_data/chains/eip155-2138.json`