> Feedback: If these docs are stale, missing, or confusing, post sanitized feedback to `https://docs.tempo.xyz/api/feedback` with `source: "mcp"`, a short `message`, and any relevant `toolName`, `relatedResource`, or `client`. # Wallet Developer Guide Tempo is EVM-compatible, so standard transactions work out of the box. However, Tempo has [no native gas token](/docs/quickstart/evm-compatibility#handling-eth-native-token-balance-checks), which means wallet behaviors like balance display and gas quoting need adjustment. To deliver the best experience for your users, integrate [Tempo Transactions](/docs/guide/tempo-transaction) — a protocol-native [EIP-2718](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-2718.md) transaction type (type byte `0x76`) that provides fee token selection, fee sponsorship, call batching, concurrent nonces, passkey signing, and scheduled execution — without requiring a bundler, paymaster, or third-party vendor. [SDKs](/docs/guide/tempo-transaction#integration-guides) are available for TypeScript, Rust, Go, Python, and Foundry. Integration typically takes less than an hour. ## Steps ::::steps ### Integrate Tempo Transactions Replace your wallet's transaction construction with Tempo Transactions. The minimum change is switching from a type-2 (EIP-1559) envelope to a type-`0x76` Tempo Transaction envelope using one of the [Tempo SDKs](/docs/guide/tempo-transaction#integration-guides). :::code-group ```ts twoslash [example.ts] // @noErrors import { client } from './viem.config' import { parseUnits } from 'viem' // Sends a Tempo Transaction (type 0x76) const { receipt } = await client.token.transferSync({ amount: parseUnits('100', 6), to: '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEbb', token: '0x20c0000000000000000000000000000000000001', }) ``` ```ts twoslash [viem.config.ts] filename="viem.config.ts" // [!include ~/snippets/viem.config.ts:setup] ``` ::: :::tip With Tempo Transactions, you can also: * Set the fee token for your users' transactions ([guide](/docs/guide/payments/pay-fees-in-any-stablecoin)) * Sponsor transaction fees for your users ([guide](/docs/guide/payments/sponsor-user-fees)) * Send concurrent transactions with independent nonces ([guide](/docs/guide/payments/send-parallel-transactions)) * Use expiring nonces for cheaper transactions that don't require nonce tracking ([guide](/docs/guide/tempo-transaction#expiring-nonces)) ::: ### Handle the absence of a native token If you use `eth_getBalance` to validate a user's balance, you should instead check the user's account fee token balance on Tempo. Additionally, you should not display any "native balance" in your UI for Tempo users. :::info In testnet, `eth_getBalance` [returns a large placeholder value](/docs/quickstart/evm-compatibility#handling-eth-native-token-balance-checks) for the native token balance to unblock existing assumptions wallets have about the native token balance. ::: :::code-group ```ts twoslash [example.ts] // @noErrors import { client } from './viem.config' const userFeeToken = await client.fee.getUserToken({ account: '0x...' }) const balance = await client.token.getBalance({ account: '0x...', token: userFeeToken.address }) ``` ```ts twoslash [viem.config.ts] filename="viem.config.ts" // [!include ~/snippets/viem.config.ts:setup] ``` ::: ### Configure native currency symbol If you need to display a native token symbol, such as showing how much gas a transaction requires, you can set the currency symbol to `USD` for Tempo as fees are denominated in USD. ### Use fee token preferences to quote gas prices On Tempo, users can pay fees in any supported stablecoin. You should quote gas/fee prices in your UI based on a transaction's fee token. :::info As a wallet developer, you can set the fee token for your user at the account level. If you don't, Tempo uses a cascading fee token selection algorithm to determine the fee token for a transaction – learn more about [Fee Token Preferences](/docs/protocol/fees/spec-fee#fee-token-preferences). ::: ### Add fee token selection to your UI Your wallet should provide a way for users to choose which stablecoin they pay fees in. This can be a dropdown in the transaction confirmation screen or a setting in account preferences. To set the fee token on a per-transaction basis, pass the `feeToken` parameter when submitting a Tempo Transaction: :::code-group ```ts twoslash [example.ts] // @noErrors import { client } from './viem.config' import { parseUnits } from 'viem' const { receipt } = await client.token.transferSync({ amount: parseUnits('100', 6), feeToken: '0x20c0000000000000000000000000000000000002', // [!code hl] to: '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEbb', token: '0x20c0000000000000000000000000000000000001', }) ``` ```ts twoslash [viem.config.ts] filename="viem.config.ts" // [!include ~/snippets/viem.config.ts:setup] ``` ::: To set a persistent default so users don't need to select on every transaction, use `setUserToken`: ```ts await client.fee.setUserTokenSync({ token: '0x20c0000000000000000000000000000000000001', }) ``` See [Fee Token Preferences](/docs/protocol/fees/spec-fee#fee-token-preferences) for the full cascading resolution order. ### Display token and network assets Tempo provides a public tokenlist service that hosts token and network assets. You can pull these assets from our public tokenlist service to display in your UI. * **GitHub**: [tempoxyz/tempo-apps/apps/tokenlist](https://github.com/tempoxyz/tempo-apps/tree/main/apps/tokenlist) * **Tokenlist JSON**: [tempoxyz.github.io/tempo-apps/42431/tokenlist.json](https://tempoxyz.github.io/tempo-apps/42431/tokenlist.json) :::: ## Already using EIP-7702 or EIP-4337? If you've integrated a third-party account abstraction provider for batching, sponsorship, or smart accounts, Tempo Transactions provide these features natively at the protocol level. See the [feature comparison](/docs/protocol/transactions/eip-7702#feature-comparison) for details. ## Recipes ### Get user's fee token Retrieve the user's configured fee token preference: ```ts import { getUserToken } from 'viem/tempo' const feeToken = await client.fee.getUserToken({ account: userAddress }) ``` See [`getUserToken`](https://viem.sh/tempo/actions/fee.getUserToken) for full documentation. ### Get token balance Check a user's balance for a specific token: ```ts import { getBalance } from 'viem/tempo' const balance = await client.token.getBalance({ account: userAddress, token: tokenAddress }) ``` See [`getBalance`](https://viem.sh/tempo/actions/token.getBalance) for full documentation. ### Set user fee token Set the user's default fee token preference. This will be used for all transactions unless a different fee token is specified at the transaction level. ```ts import { setUserToken } from 'viem/tempo' await client.fee.setUserTokenSync({ token: '0x20c0000000000000000000000000000000000001', }) ``` See [`setUserToken`](https://viem.sh/tempo/actions/fee.setUserToken) for full documentation. ## Checklist Before launching Tempo support, ensure your wallet: * \[ ] Integrates Tempo Transactions for transaction submission * \[ ] Checks fee token balance instead of native balance * \[ ] Hides or removes native balance display for Tempo * \[ ] Displays `USD` as the currency symbol for gas * \[ ] Quotes gas prices in the user's fee token * \[ ] Provides fee token selection in the UI (dropdown or account setting) * \[ ] Pulls token/network assets from Tempo's tokenlist * \[ ] (Recommended) Sponsors fees for your users via [fee sponsorship](/docs/guide/payments/sponsor-user-fees) * \[ ] (Recommended) Uses [expiring nonces](/docs/guide/tempo-transaction#expiring-nonces) for lower-cost transactions that don't require nonce management ## Learning Resources