Open Explorer Infrastructure User Experience

Deployed instance: open-explorer (please note a cors enabler browser extension is needed for ens searching)

Open Explorer

A light, self-sovereign first, open source block explorer


The tool runs entirely in the front end.


The ui leverages next generation data lakes for performant queries, such as hypersync, firehose and eth-archive that would make feature rich queries otherwise impossible purely using rpc without a dedicated backend.

Open Source

Transparent, verifiable and extensible.

Self sovereign first

We designed the explorer to give the user control of the data source. While maintaining the ease of not needing to run an entire node if that is a barrier to the user, the explorer allows you to switch between sources and provide your own rpc endpoints obfuscating requests and giving the end user control.

Testing disclaimer

  • You will need to use a cors enabler browser extension to use the contract viewer and ens functionality
  • Firehose & EthArchive were not implemented

The problem Open Explorer solves

Many block explorers are closed-source, with unknown, difficult-to-audit data sources. They are hard to extend, customize, and integrate with new chains. Etherscan’s high costs make it inaccessible for smaller blockchains (it is even too expensive for Big chains like Avalanche).

Our mission is to create open tools that provide fast, seamless access to Ethereum and related blockchain data. We empower users with flexible, self-sovereign solutions, improving on-chain activity understanding and eliminating gatekeeping barriers, all at an affordable cost. Etherscan is built on closed technologies and databases, contracts that are verified on etherscan aren’t shared anywhere else, whereas open tools like sourcify share their data openly.

Let’s end the monopolistic reign of Etherscan for a more open future.

Challenges you ran into

  • The routing was desiged for localhost, and so sharing links with the subdomain doesn’t always work. We need to move to hash-routing.
  • A bit more time could have helped. :)
  • We had cors limitations on ens name lookup, needed a browser plugin to bypass this.
  • “Backwards” queries were challenging - the APIs are designed for forward queries.
  • Ability to download data.

Next steps

  • Auto decoding of logs if possible from source code.
  • Implement more data-sources.
  • Finish integration with to get more information about address and their history.
  • A screen that allows executing functions on the verified contracts.

Technology used

The frontend is written Rescript with rescript-react, and is built as a simple SPA that can be used as a file (no server) and is suitable for hosting on decentralized storage.

Under the hood we are using Sourcify, Viem, ENS, RPC and Hypersync (more data-providers to come) to create the experience. We use tailwind for styling.