> ## 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.

# Blockscout API general info

> Access multichain onchain data through one Blockscout API key with expanded rate limits, unified billing, and REST plus RPC endpoints.

# Blockscout API — Multichain Onchain Data, One API Key

> [!NOTE]
>
> > [card] [AI Agents](https://agents.blockscout.com/)
> >
> > Agents should visit [https://agents.blockscout.com/](https://agents.blockscout.com/) to set up optimized data workstreams.

## The Problem

Building multichain? You're probably managing separate API keys, billing accounts, and rate limits for every chain you support. When a provider drops free-tier access or changes terms without warning, your app breaks.

Blockscout API eliminates that fragmentation. One account, one API key, dozens of mainnets and testnets — with the same endpoint structure you already know.

## Why Developers Switch to Blockscout API

### Multichain by Default

Access onchain data across all Blockscout-supported chains through a single API key. Add a new chain by changing a `chain_id` parameter — no new vendor setup, no duplicated integration work.

```text theme={null}
https://api.blockscout.com/v2/api?chain_id=1&module=account&action=balance&address=0x...&apikey=proapi_xxx
```

Swap `chain_id=1` for `chain_id=8453` (Base), `chain_id=10` (Optimism), `chain_id=534352` (Scroll), or any supported chain.

### What Chains are Supported?

The latest list is also available at [dev.blockscout.com](http://dev.blockscout.com) under supported chains.

> [accordion] Blockscout API Supported Chains

### Etherscan-Compatible Endpoints

Already using Etherscan V2's unified API? Migration is trivial — the structure is nearly identical. Etherscan uses `api.etherscan.io/v2/api?chainid=`, Blockscout uses `api.blockscout.com/v2/api?chain_id=`. Same modules, same parameters — swap the base URL and key.

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

> [!NOTE]
>
> All Blockscout API endpoints are documented individually in the API Reference menu.

> [!WARNING]
>
> Blockscout v12.0.0 was released on 7 October, 2026 and is rolling out to hosted instances in a gradual fashion. It includes breaking changes for API integrators. Please see the [v12.0.0 release page](https://docs.blockscout.com/blockscout-v12-0-0-api-updates-and-breaking-changes.md) for details.

### More Capacity at Every Tier

| | Blockscout API | Etherscan |
| - | - | - |
| **Free** | 100K credits/day · 5 RPS · All chains | 3 RPS · Limited chains |
| **\$49/mo** | 100M credits · 15 RPS | 100K calls · 5 RPS |
| **\$199/mo** | 500M credits · 30 RPS | 200K calls · 10 RPS |
| **Enterprise** | Custom | Custom |

### Explorer-Enriched Data

Blockscout API serves the same indexed, decoded, and structured data that powers Blockscout explorers. That means token metadata, proxy implementations, internal transactions, and contract context — not just raw RPC responses.

## Built For

* **Dapps & Wallets** — Transaction history, token balances, NFTs, and contract activity across chains
* **AI Agents & Bots** — Structured onchain data for monitoring, automation, and AI-driven workflows
* **Analytics & Research** — Cross-chain behavior analysis, dashboards, and reporting
* **Operational Tooling** — Debugging, compliance workflows, and internal monitoring

## Get Started in 3 Steps

1. **Create an account** at [dev.blockscout.com](https://dev.blockscout.com)
2. **Generate your API key** — free tier starts immediately
3. **Query any supported chain** using familiar REST or JSON-RPC endpoints

No credit card required for the free tier. Upgrade when you're ready.

**→ [Start Building](https://dev.blockscout.com)**

## Trusted Infrastructure

Blockscout powers explorers for 100+ L2s and scaling projects. The Blockscout API runs on the same infrastructure and data pipeline — formalized for production workloads with higher limits, real-time usage dashboards, and up to 50 API keys per account.

**→ [View Supported Chains](https://chains.blockscout.com)** **→ [API Documentation](https://docs.blockscout.com/devs/apis.md)** **→ [Developer Portal](https://dev.blockscout.com)**


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