# Base API

The Crypto APIs Base API, part of the Blockchain API, lets you read balances, token transfers and blocks on Base and send transactions without running a node. One API key covers mainnet and sepolia. Webhooks tell your server when a payment confirms, and we never hold your private keys.

## Key facts

| | |
| --- | --- |
| Networks | Mainnet, Sepolia |
| Model | Account (EVM) |
| Endpoints | 34 |
| Confirmations webhook | Yes, per address |
| Custody | Non-custodial, you sign |
| Free trial | 14 days, no card |

## How do I get the latest Base block?

Send one GET request with your API key; the same request works on sepolia when you replace mainnet with sepolia in the path.

```
curl https://rest.cryptoapis.io/blocks/evm/base/mainnet/latest/details \
  -H "X-API-Key: YOUR_API_KEY"
```

## Which Base endpoints are available?

The main calls. Every path takes the network: mainnet or sepolia.

| What it does | Method and path | Reference |
| --- | --- | --- |
| Latest block | `GET /blocks/evm/base/mainnet/latest/details` | [Docs](https://developers.cryptoapis.io/v-2.2024-12-12-175/RESTapis/blocks-evm/get-last-mined-block-evm/get) |
| Block by height | `GET /blocks/evm/base/mainnet/height/{blockHeight}/details` | [Docs](https://developers.cryptoapis.io/v-2.2024-12-12-175/RESTapis/blocks-evm/get-block-details-by-block-height-evm/get) |
| Address balance | `GET /addresses-latest/evm/base/mainnet/{address}/balance` | [Docs](https://developers.cryptoapis.io/v-2.2024-12-12-175/RESTapis/address-latest-evm/get-address-balance-evm/get) |
| Transactions of an address | `GET /addresses-latest/evm/base/mainnet/{address}/transactions` | [Docs](https://developers.cryptoapis.io/v-2.2024-12-12-175/RESTapis/address-latest-evm/list-confirmed-transactions-by-address-evm/get) |
| Token transfers of an address | `GET /addresses-latest/evm/base/mainnet/{address}/tokens-transfers` | [Docs](https://developers.cryptoapis.io/v-2.2024-12-12-175/RESTapis/address-latest-evm/list-confirmed-tokens-transfers-by-address-evm/get) |
| Transaction by hash | `GET /transactions/evm/base/mainnet/{transactionHash}` | [Docs](https://developers.cryptoapis.io/v-2.2024-12-12-175/RESTapis/transactions-data-evm/get-transaction-details-by-transaction-hash-evm/get) |
| Fee recommendations | `GET /blockchain-fees/evm/base/mainnet/mempool` | [Docs](https://developers.cryptoapis.io/v-2.2024-12-12-175/RESTapis/blockchain-fees-evm/get-fee-recommendations-evm/get) |
| Prepare an unsigned transaction | `POST /prepare-transactions/evm/base/mainnet/native-coins` | [Docs](https://developers.cryptoapis.io/v-2.2024-12-12-175/RESTapis/prepare-transactions-evms/prepare-transaction-from-address-evm/post) |
| Broadcast a signed transaction | `POST /broadcast-transactions/base/mainnet` | [Docs](https://developers.cryptoapis.io/v-2.2024-12-12-175/RESTapis/broadcast-locally-sign-transactions/broadcast-locally-signed-transaction/post) |
| Webhook on a confirmed payment | `POST /blockchain-events/base/mainnet/address-coins-transactions-confirmed` | [Docs](https://developers.cryptoapis.io/v-2.2024-12-12-175/RESTapis/create-subscriptions-for/new-confirmed-coins-transactions/post) |

## Base API questions

**Is there a free Base API?** You can try it free for 14 days. The Blockchain API free trial covers Base and every feature, with no card. It ends after 14 days or when its credits run out; after that, calls need a subscription, listed on the pricing page.

**How do I get the balance of a Base address?** Call the address balance endpoint with the address; it returns the confirmed ETH balance. Token balances live in the token contracts, so list the address's token transfers to see them.

**How do I broadcast a Base transaction?** Sign the transaction on your own server, then send the signed raw transaction to the broadcast endpoint, authenticated with your API key, and Crypto APIs pushes it to the Base network and returns the transaction ID. We can prepare the unsigned transaction for you first.

**Do you support Base sepolia?** Yes. Every Base endpoint works on mainnet and sepolia. Change mainnet to sepolia in the path; the same API key works on both.

**What makes Base different to work with?** It is an account-model EVM chain — every address has a single balance and a nonce. Tokens live in their own contracts rather than in the account balance, so reading them means calling the token contract; and every transaction needs the account's next nonce, which the same API returns.

**How do I know when a Base transaction is confirmed?** Create a webhook subscription for the address. Crypto APIs calls your URL when a transaction to or from it confirms on Base.

## What makes Base blockchain different?

Base, an Ethereum L2 platform, enables swift integration of EVM codebases and assets from Ethereum L1, Coinbase and other chains, ensuring cost-effectiveness and security.

Base, an Ethereum L2 platform, ensures security, stability, and scalability for on-chain applications. Any EVM codebase can be deployed to allow onboarding users and assets from Ethereum L1, Coinbase, and other chains. Integration with existing tools thanks to EVM compatibility is made possible. Additionally, its rollup architecture reduces user costs by 10x.

| About Base | |
| --- | --- |
| Released | 2023 |
| Consensus | ЕTH Bridge L2 |
| Block time | ~2 seconds |
| Smart contracts | Yes |

## Other EVM chains, same request shape

- [Optimism API](/chains/optimism)
- [Arbitrum API](/chains/arbitrum-one)
- [Ethereum API](/chains/ethereum)

## Pointers

- [Blockchain API](/products/blockchain-api)
- [All networks](/what-we-support)
- [Pricing](/pricing)
- [Developer portal](https://developers.cryptoapis.io/)