> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nebulaonchain.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Configuring Nebula for Stellar Testnet and Mainnet

> Configure Nebula for Stellar testnet or mainnet. Testnet is the default — switch to mainnet by setting NETWORK=mainnet in your MCP config.

Nebula defaults to Stellar **testnet** so you can explore every feature with no financial risk. When you are ready to use real funds, switching to mainnet is a single environment variable change. The two networks share the same tool interface, but differ in how you fund your wallet, which USDC issuer is used, and which on-chain contracts back treasury and identity features.

## Testnet vs. mainnet comparison

| Feature                  | Testnet                         | Mainnet                              |
| ------------------------ | ------------------------------- | ------------------------------------ |
| **Default**              | ✅ (no config needed)            | Set `NETWORK=mainnet`                |
| **Funding method**       | Friendbot via `request_funding` | Fund manually with real XLM and USDC |
| **USDC issuer**          | Circle testnet SAC              | Circle mainnet issuer                |
| **Blend treasury**       | Testnet lending pools           | Verify pool availability before use  |
| **Stellar8004 identity** | Testnet contracts               | Mainnet contracts                    |
| **Transaction cost**     | Free (test tokens)              | Real XLM fees                        |

***

## Getting started on testnet

Follow these three steps to have a fully funded testnet agent ready to send payments and earn yield.

**Step 1 — Fund XLM using Friendbot**

Ask your agent to call `request_funding`. Nebula returns a Friendbot link that credits your wallet with 10,000 test XLM in seconds.

```text theme={null}
Use request_funding from Nebula
```

**Step 2 — Add a USDC trustline and get test USDC**

USDC transfers and x402 payments require a USDC trustline on your wallet. Visit the Circle testnet faucet to establish the trustline and receive test USDC:

[https://faucet.circle.com/](https://faucet.circle.com/)

Select **Stellar Testnet**, paste your wallet address (from `get_address`), and the faucet establishes the trustline and sends test USDC automatically.

**Step 3 — Set spending limits**

Add `MAX_PER_CALL` and `MAX_PER_DAY` to your MCP config to authorize your agent to spend. Start conservatively and increase them once you are comfortable with the behavior.

```json theme={null}
{
  "mcpServers": {
    "nebula": {
      "command": "npx",
      "args": ["-y", "nebula-mcp"],
      "env": {
        "STELLAR_SECRET_KEY": "S...",
        "NETWORK": "testnet",
        "MAX_PER_CALL": "10",
        "MAX_PER_DAY": "100"
      }
    }
  }
}
```

<Tip>
  Once funded, run `Use wallet_dashboard from Nebula` to see balances, limits, and treasury status all in one interactive view.
</Tip>

***

## Switching to mainnet

When you are ready to go live, follow these steps in order.

**1. Set `NETWORK=mainnet` in your MCP config**

```json theme={null}
{
  "mcpServers": {
    "nebula": {
      "command": "npx",
      "args": ["-y", "nebula-mcp"],
      "env": {
        "STELLAR_SECRET_KEY": "S...",
        "NETWORK": "mainnet",
        "MAX_PER_CALL": "10",
        "MAX_PER_DAY": "100"
      }
    }
  }
}
```

**2. Fund your wallet with real XLM and USDC**

Friendbot is not available on mainnet. Acquire XLM from an exchange and send it to your wallet address. For USDC, use the Circle mainnet issuer or a supported exchange. Keep enough XLM for transaction fees (the `XLM_FEE_BUFFER` default is 5 XLM).

<Note>
  Stellar transaction fees are extremely low — typically fractions of a cent per transaction. The 5 XLM fee buffer is more than enough to cover thousands of transactions, so your agent can operate economically even when making frequent payments or rebalancing the treasury.
</Note>

**3. Deploy an on-chain policy for stronger enforcement**

Off-chain limits work well for testing, but for production use you should deploy a Soroban policy contract. This creates a tamper-proof on-chain audit trail of every spend.

```text theme={null}
Use deploy_policy from Nebula with max_per_call 10 and max_per_day 100
```

Copy the returned `POLICY_CONTRACT_ID` into your MCP env and remove `MAX_PER_CALL` / `MAX_PER_DAY` (or keep them as documentation — they are ignored once a policy contract is set).

**4. Verify Blend pool availability**

Blend lending pools on mainnet may differ from testnet. Run `blend_check_rates` and `get_treasury_status` to confirm the pools you intend to use are active and returning expected APY before enabling the background rebalancer.

<Warning>
  Never use a mainnet secret key (`STELLAR_SECRET_KEY`) in a testnet configuration, or a testnet key in a mainnet configuration. The Stellar networks are completely separate — a key generated for one network has no funds on the other, and sending transactions to the wrong network will fail silently or consume real fees for no effect.
</Warning>

<Note>
  Always test your full agent workflow on testnet before switching to mainnet. Testnet resets periodically, but it faithfully mirrors mainnet behavior for all Nebula features.
</Note>