Blockscout review: the open challenger to Etherscan

Blockscout is the explorer you have probably used without noticing. It is the explorer Gnosis Chain documents for its mainnet, the canonical explorer of a long list of rollups, one of the explorers listed in Base’s docs, and on Ethereum mainnet it lives at eth.blockscout.com. It is also what powers the live Ethereum explorer on this site. This Blockscout review looks at it as an Ethereum mainnet explorer first: how the address details and transaction pages read, how contract verification works, how generous the API really is, and where it still loses to Etherscan. We tested the production instance, running backend v11.3.2, on 24 September 2026.

From POA Network side project to multichain standard

Blockscout started in 2018 at POA Network, with support from an ETHPrize grant. The pitch was simple and, at the time, unusual: a full-featured Ethereum block explorer whose entire code base was public, so any chain could run its own copy instead of begging a closed-source company for coverage. The beta landed on GitHub in August 2018 and the first releases followed that autumn. The backend is written in Elixir, which handles the flood of concurrent indexing jobs well, and a separate Next.js frontend followed in 2022.

The bet paid off with the rise of rollups. Every new layer 2 needs an explorer on day one, and Blockscout was the one you could deploy without negotiation. Today it serves more than 100 chains; the Blockscout blog put its free API coverage at over 120 chains in July 2026. OP Stack documentation points chain operators to it, Gnosis documents it for its mainnet and Chiado testnet, and a self-service launchpad called Autoscout can spin up a hosted instance from little more than an RPC URL. Our layer 2 explorer guide shows which networks use it as their default.

The 2026 licence change, explained plainly

For most of its life Blockscout was licensed under GPL-3.0, and many articles still say so. That changed on 22 April 2026, when Blockscout v11.0.0 moved to a new, source-available Blockscout Software Licence. Versions up to backend v10.2.0 and frontend v2.7.1 stay GPL-3.0 forever. Newer versions are still public, free to download, run and modify, and free to deploy for your own chain. What is restricted is reselling: hosted-explorer providers and rollup-as-a-service platforms now need a commercial licence, derivative works may not be redistributed without one, and every interface built on Blockscout must display a “Powered by Blockscout” credit.

For a user of eth.blockscout.com none of this changes anything. For a team deciding whether to self-host, it is worth reading the licence page carefully. Strictly speaking, current Blockscout is no longer “open source” in the OSI sense, and we score it accordingly. Our guide to open-source Ethereum explorers covers alternatives that remain under permissive licences.

The Blockscout Ethereum address explorer: address details page

Search for vitalik.eth and Blockscout resolves the ENS name to 0xd8dA…6045 and opens the address details page. The top card shows the ETH balance with its dollar value, a token dropdown with net worth, counters for transactions and transfers, gas used, and the block at which the balance was last updated. That last detail is small but honest: it tells you how fresh the number is.

Here is where Blockscout showed its strength in our test. Vitalik’s address is not a plain wallet any more. Since Pectra, it carries an EIP-7702 delegation, and Blockscout flags it clearly: the address is marked as delegated, with the implementation contract (AmbireAccount7702) linked right on the page. That is exactly the information you need to understand why an externally owned account suddenly behaves like a smart contract. If you want to learn what such flags mean for your own wallet’s security, our Ethereum address explorer guide walks through them.

Below the card, tabs split the history into transactions, token transfers, tokens held, internal transactions, coin balance history (a chart of ETH balance over time), logs, and beacon chain withdrawals for validator payout addresses. Contracts get a Contract tab with source, ABI and Read/Write sections. Lists can be exported to CSV; since v11 exports run as background jobs, so large files no longer time out. Addresses flagged as scams show a clear warning, which is worth a second look before you interact with anything.

1. 1 STEP 01

   Open eth.blockscout.com and paste the address

   Type the 42-character address or an ENS name such as vitalik.eth into the search bar. Check that the network badge says Ethereum, not a rollup or testnet instance.

2. 2 STEP 02

   Read the details card

   Look at the ETH balance, the token count and net worth, and the flags: contract or wallet, verified or not, proxy or EIP-7702 delegation, and any scam warning.

3. 3 STEP 03

   Scan the tabs for unexpected activity

   Open Token transfers and Internal txns. Unknown tokens, zero-value transfers from lookalike addresses, or outgoing transfers you did not sign are red flags.

4. 4 STEP 04

   Cross-check a second source

   Paste the same address into another explorer. The numbers should match to the wei; if they do not, one indexer is behind. Blockscout shows the block at which the balance was last updated.

The Blockscout transaction explorer page

A Blockscout transaction page opens with the status, the block number with its confirmation count, and the time it took to confirm. On many transactions a one-line summary interprets what happened, for example a swap or a token transfer, and method names are decoded when the contract is verified. From, to, value and fee come next, followed by the full EIP-1559 breakdown: gas limit and gas used, base fee, max and priority fee, and burnt fees. Transaction types are labelled (EIP-1559, blob, set-code), and the raw input can be viewed as hex or UTF-8.

The tabs are where it gets interesting for power users. Besides token transfers, internal transactions and logs, Blockscout offers a State tab with balance changes and a Raw trace tab with the full call tree. Blob transactions get a dedicated blob section with blob hashes, size and blob gas, which Blockscout supported from the moment Dencun activated on 13 March 2024. Set-code transactions show their authorization list, so you can see which EOA delegated to which contract. ERC-4337 user operations have their own index as well. For a field-by-field explanation of any explorer’s transaction view, see our Ethereum transaction explorer guide.

Tokens and NFTs

Token pages list holders, transfers, total supply, decimals and price where available, with an inventory view for NFT collections that renders images and metadata. Search works on names and tickers, so typing “WETH” finds 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 immediately. Token metadata is thinner than on Etherscan: fewer official links, fewer reputation notes, fewer logos for small tokens. For due diligence on an unknown token, combine it with the checks in our Ethereum token explorer guide and our NFT explorer guide.

Contract verification and Sourcify

Blockscout accepts verification from its own UI, from its API, and through Hardhat, Foundry, Remix and thirdweb. The distinctive part is Sourcify, an open, explorer-neutral repository of verified contracts that grew out of the Ethereum Foundation ecosystem. Contracts verified on Sourcify show up as verified on Blockscout, so your proof is not locked inside one company’s database. Once verified, the Read and Write tabs let you call functions from the browser, including through proxies. Because Blockscout exposes an Etherscan-compatible verification endpoint, most toolchains need nothing more than a different URL. Our smart contract explorer guide covers what verification proves and what it does not.

The Blockscout Ethereum mainnet explorer API

This is where Blockscout pulls ahead of everyone. Each instance exposes two interfaces. The REST API v2 (for example https://eth.blockscout.com/api/v2/addresses/<address>) returns rich, decoded JSON: ENS names, token metadata, proxy implementations, scam flags, decoded inputs, even the network’s gas price and ETH price through /api/v2/stats. The RPC API at /api?module=account&action=balance… mirrors the Etherscan format, so scripts written for Etherscan often work by swapping the base URL.

Both answer without an API key. According to the Blockscout docs, the default keyless limit is 300 requests per minute per IP, a free key from your account raises it to 10 requests per second, and browser users who hit the limit can solve a captcha for a temporary 5-per-second token. For multichain work there is the PRO API at api.blockscout.com, which needs a key and offers a free plan of 100,000 credits per day at 5 RPS across all supported chains, with paid plans from $49 per month. The docs also warn that per-instance API access is being phased out in favour of the PRO API, so plan for a key in production. At the time of our test the keyless endpoints on eth.blockscout.com still answered normally.

Because no secret is needed, you can call Blockscout straight from front-end code, which is exactly how our live explorer works: your browser fetches the data directly, with no server of ours in between. Compare that with Etherscan, whose free tier now requires a key, covers fewer chains and returns at most 1,000 records per call. The full comparison, with code samples, is in our Ethereum explorer API guide. Developers who work with AI agents will also like the official Blockscout MCP server, which exposes the same data to tools such as Claude or Cursor.

Self-hosting Blockscout

Running your own instance is the other big draw. You need an archive node such as Erigon, Nethermind or Geth, a PostgreSQL database and the Blockscout backend and frontend, typically deployed with Docker Compose or the official Helm charts. For a private network or a devnet, it is the most complete explorer you can run yourself. For Ethereum mainnet it is a serious undertaking: indexing more than 26 million blocks and over 3.7 billion transactions takes substantial disk space and days of sync time. If you only need a private view of your own node, a lighter tool such as Otterscan may be the smarter choice. Remember the licence: self-hosting for your own use is fine, charging others for access to it is not without a commercial agreement.

Speed of shipping: blobs, EIP-7702 and beyond

Blockscout’s best habit is being ready on upgrade day. Blob transactions were explorable the moment Dencun went live. For Pectra in May 2025 the team prepared support for EIP-7702 delegations, authorization lists and set-code transactions, and published a guide explaining them. Recent releases added features such as asynchronous CSV exports, a much smaller internal-transactions table for faster queries, and early support for fully homomorphic encryption chains. There is even a gamified layer: Merits, points you earn for using the explorer, which Blockscout stresses have no monetary value. You can ignore them entirely; they do not get in the way.

Where Blockscout still trails Etherscan

No review is complete without the downsides. The biggest is labels. Etherscan has spent a decade tagging exchange wallets, protocol contracts and exploiters, and Blockscout’s public tags are fewer, so an unknown address is more often just hex. Token metadata is thinner too, and the analytics section offers fewer charts. Etherscan’s plain-English transaction summaries still cover more protocols.

Account features are more modest: Blockscout offers watchlists, private tags and API keys, and approval management lives in a separate Revoke app among its “essential dapps” rather than on the address page itself, which feels less integrated than Etherscan’s approval checker. The interface occasionally shows a counter capped at a round number for very active addresses until you open the tab, and the indexer can lag a few seconds behind the chain head at busy moments. Finally, the licence change means the “fully open source” argument no longer applies to new versions. None of these is a deal-breaker, but they explain why we place it just behind Etherscan in our 2026 explorer ranking and among the first names in our list of Etherscan alternatives.

Final verdict: who should use eth.blockscout.com?

If you are a developer, Blockscout should probably be your default data source: the keyless API is the most useful free tier on Ethereum today, and the Etherscan-compatible layer makes switching painless. If you work across rollups, learning one interface pays off on dozens of chains. And if you just want a second opinion on a transaction, it is clean, quick and far less cluttered than the market leader.

Beginners who rely on labels to understand who they are dealing with will still find Etherscan friendlier, and teams that need strictly open-source software for compliance should read the new licence before deploying. For everyone else, 8.9 out of 10 feels right: a first-class explorer, and the healthiest counterweight to a single company owning Ethereum’s window onto its own data. Want to see it in action right now? Paste an address into our Blockscout-powered live explorer, or learn the basics in our guide on how to use an Ethereum block explorer.