# Fund Gas Tanks

Source: https://developers.bitgo.com/docs/get-started-gas-tanks

## Overview

Gas tanks are enterprise-level fee wallets that BitGo uses to pay blockchain transaction fees (gas) on your behalf for EVM-based assets. When you send an ERC-20 token, for example, the gas fee is paid in the chain's native asset (ETH for Ethereum, MATIC for Polygon, etc.). Your gas tank holds that native asset.

## Asset Gas Tank Requirements 

**General rule:** Any asset on an EVM-based chain requires a gas tank. This includes both the chain's native asset (ETH, MATIC, BNB, etc.) and any tokens on that chain (ERC-20, ERC-721, etc.). Most other non-EVM chains pay consolidation or transaction fees from the receive address or sender directly.

**Exception — TRON:** [TRON](/docs/tron) uses a TRX gas tank to fund receive addresses for **TRC-20 token consolidation** (not for all TRX transaction types). Contact [support@bitgo.com](mailto:support@bitgo.com) to enable auto-funding; BitGo sets the `enableTrxFundingFromGasTank` enterprise flag after setup.

Check the Gas Tank on the BitGo app for more information.

> 📘 **Note**
>
> If you're only working with Bitcoin or other non-EVM assets (other than TRON token consolidation) during development, you can skip this page and come back when needed.

## 1. Get Testnet Native Coins

Before you can fund a gas tank, you need native testnet coins. See the [faucet table on the Environments page](https://developers.bitgo.com/docs/get-started-environments) to obtain them.

For Ethereum (Holesky testnet), get htETH from the [Google Cloud Holesky faucet](https://cloud.google.com/application/web3/faucet/ethereum/holesky).

## 2. Find Your Gas Tank Address

Funding your gas tank requires using the BitGo web application:

1. Log in to [https://app.bitgo-test.com](https://app.bitgo-test.com)
2. Click the **Gas Tanks** icon in the top navigation bar, next to the Activity bell.
3. Find the gas tank for the chain you need (e.g., `hteth` for Holesky Ethereum).
4. Click **Deposit**.
5. Copy the deposit address or scan the QR code.

## 3. Send Testnet Coins to the Gas Tank

Send native testnet coins from the faucet (or from another wallet you control) to the gas tank address you copied in Step 2.

## 4. Verify Your Gas Tank Balance

Confirm you funded your gas tank by calling the fee address balance endpoint:

>Endpoint: [Get Gas Tank Balance](/reference/v2enterprisefeeaddressbalance)

```shell cURL
export ENTERPRISE_ID="<your-enterprise-id>"
export BITGO_ACCESS_TOKEN="v2x..."

curl "https://app.bitgo-test.com/api/v2/hteth/enterprise/$ENTERPRISE_ID/feeAddressBalance" \
  -H "Authorization: Bearer $BITGO_ACCESS_TOKEN"
```

> 📘 **Note**
>
> You can find your Enterprise ID in the BitGo web app under **Settings > Enterprise Settings**, or from the response of `GET /api/v2/user/{id}` in the `enterprises` array.

## Funding Amount

For testnet development, a small amount is sufficient — 0.1 htETH is plenty for hundreds of test transactions. In production, monitor your gas tank balance and set up a [webhook](https://developers.bitgo.com/docs/webhooks-overview) to alert you when the balance drops below a threshold.

## Next Steps

Go to **[Install SDK](https://developers.bitgo.com/docs/get-started-sdk-install)** or **[Install Express](https://developers.bitgo.com/docs/get-started-express-install)** to set up your development environment.

## See Also

- [TRON](/docs/tron) — TRX gas tank for TRC-20 consolidation
- [API Reference: Get Gas Tank Balance](/reference/v2enterprisefeeaddressbalance)
- [Withdrawal Fee Sources](/docs/withdrawal-fees) — Where withdrawal transaction fees are deducted from, by asset
- [Consolidations](/docs/consolidations) — Consolidation fee sources by asset and wallet version