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

# Base API

# Base Blockchain API  with Free Access and No Cutoffs

> Full block explorer API for Base developers. Free tier on all endpoints. No surprise restrictions.

## Base API Access with Blockscout

Base is Coinbase's Ethereum L2 and one of the fastest-growing chains in the ecosystem. With its 2026 strategy focused on tokenized markets, stablecoin payments, and developer tooling, Base has become a magnet for consumer dapps, DeFi, SocialFi, and AI agent applications. Its TVL has grown into the multi-billion dollar range, and hundreds of teams are building across the stack.

When other API providers removed free-tier access for Base, many developers were left scrambling. Blockscout PRO API provides full API access for Base — with a free tier that isn't going anywhere.

**Base Chain ID:** `8453` \
**Explorer:** [base.blockscout.com](https://base.blockscout.com) \
**PRO API Base:** `https://api.blockscout.com` (use `chain_id=8453`) \
**API Docs:** [base.blockscout.com/api-docs](https://base.blockscout.com/api-docs)

## Quick Start

Get your first API response in under 60 seconds:

```bash theme={null}
# Get ETH balance for an address on Base via PRO API
curl "https://api.blockscout.com/v2/api?chain_id=8453&module=account&action=balance&address=0xYOUR_ADDRESS&apikey=proapi_YOUR_KEY"
```

Get a free API key at [dev.blockscout.com](https://dev.blockscout.com) — required for all PRO API tiers, including free.

## PRO API Routes for Base

All routes use Base's chain ID (`8453`):

**JSON RPC v2 (Etherscan-compatible):**

```text theme={null}
https://api.blockscout.com/v2/api?chain_id=8453&module=account&action=txlist&address=0x...&apikey=proapi_xxx
```

**JSON RPC:**

```text theme={null}
https://api.blockscout.com/8453/api?module=account&action=txlist&address=0x...&apikey=proapi_xxx
```

**REST API:**

```text theme={null}
https://api.blockscout.com/8453/api/v2/addresses/0x.../transactions?apikey=proapi_xxx
```

**ETH RPC (POST):**

```bash theme={null}
curl -H "content-type: application/json" \
  -H "authorization: Bearer proapi_xxx" \
  -X POST \
  --data '{"id":0,"jsonrpc":"2.0","method":"eth_blockNumber","params":[]}' \
  https://api.blockscout.com/8453/json-rpc
```

## Available Endpoints

### Etherscan-Compatible Modules

All standard modules work — if you've used Etherscan's Base API before, the same parameters apply:

* **Account** — Balances, transaction lists, token transfers, internal transactions, ERC-20/721/1155 activity (plus Blockscout extras: `eth_get_balance`, `pendingtxlist`, `tokenbalance`, `tokenlist`)
* **Contract** — ABI, source code, verification (plus: `listcontracts`, `getcontractcreation`, Vyper & Sourcify verification)
* **Transaction** — Status checks (plus: `gettxinfo`)
* **Logs** — Event logs with filtering by address, topics, block range
* **Token** — Token metadata, holders
* **Stats** — Supply, chain statistics, coin price
* **Block** — Block rewards, countdown, block number by time
* **Gas Tracker** — Gas oracle, gas estimates

### REST API

Blockscout's native REST API provides enriched metadata, decoded input data, NFT media and attributes, smart contract read/write interaction, and chain health monitoring — all accessible through the PRO API.

**→ [Full REST API Reference](https://base.blockscout.com/api-docs)**

## Base API Pricing

| Tier       | Rate Limit | Credits  | Price      |
| ---------- | ---------- | -------- | ---------- |
| Free       | 5 RPS      | 100K/day | \$0        |
| Builder    | 15 RPS     | 100M/mo  | \$49/mo    |
| Pro        | 30 RPS     | 500M/mo  | \$199/mo   |
| Business   | 50 RPS     | 3B/mo    | \$999/mo   |
| Enterprise | Custom     | Custom   | Contact us |

Every tier includes access to all 117 Blockscout-supported chains — not just Base. One API key, one account, one `chain_id` parameter swap to query any network.

## Switching from Etherscan's Base API?

Etherscan lists Base as paid-only (`⚠️`). Blockscout provides free access on all tiers. Since both APIs now use a unified multichain format, the migration is a base URL and key swap:

```javascript theme={null}
// Before (Etherscan V2 — Base requires paid tier)
const resp = await fetch(
  `https://api.etherscan.io/v2/api?chainid=8453&module=account&action=balance&address=${addr}&apikey=${ETHERSCAN_KEY}`
);

// After (Blockscout PRO API — free tier available)
const resp = await fetch(
  `https://api.blockscout.com/v2/api?chain_id=8453&module=account&action=balance&address=${addr}&apikey=${BLOCKSCOUT_KEY}`
);
```

Same structure: `chainid` → `chain_id`, swap the base URL and key.

**→ [Full Migration Guide](https://docs.blockscout.com/devs/migrate-from-etherscan)**

## What Developers Build on Base with Blockscout's API

**Consumer Dapps & SocialFi** — Base is home to Farcaster, Zora, and a growing SocialFi ecosystem. Blockscout's API powers transaction history, token balances, and NFT data for these applications.

**DeFi Backends** — With billions in TVL across DEXs, lending markets, and yield platforms, Base DeFi apps rely on explorer APIs for contract data, event monitoring, and position tracking.

**AI Agents & Automation** — Base's 2026 roadmap includes native support for AI agent smart accounts. Blockscout's PRO API and MCP server provide the structured onchain data these agents need.

**Wallets & Portfolio Trackers** — Pull complete transaction histories, multi-token balances, and NFT holdings for Base addresses through a single API key that also covers every other chain.

## Base on Blockscout

As part of the OP Superchain, Base benefits from Blockscout's native support for L1↔L2 transaction tracking, including deposit and withdrawal views and cross-chain message debugging. Blockscout provides free API access for Base where Etherscan requires a paid plan — and over 84 chains run Blockscout as their exclusive explorer. With the PRO API's multichain architecture, querying Base is just one `chain_id` parameter away from querying Ethereum, Optimism, Arbitrum, or any other supported network.

## Get Started

1. Get a free API key at [**dev.blockscout.com**](https://dev.blockscout.com)
2. Use `chain_id=8453` in your PRO API requests
3. Explore endpoints at [**base.blockscout.com/api-docs**](https://base.blockscout.com/api-docs)

**→ [Start Building on Base](https://dev.blockscout.com)** · **→ [PRO API Routes Reference](https://docs.blockscout.com/devs/pro-api-responses-and-routes)**