Developer Tools
Block Explorers

Block Explorers

This reference guide lists different block explorers you can use to interact with contract source code and view transaction history for OP Mainnet and OP Sepolia.


This page includes providers that meet specific inclusion criteria, as outlined below. Please visit the community block explorers page (opens in a new tab) for an additional listing of third-party block explorers.


We have a Blockscout explorer for OP Mainnet (opens in a new tab) and OP Sepolia (opens in a new tab). It includes:

Blockscout also has some OP-Mainnet-specific features:


We have Etherscan explorers for the OP Mainnet (opens in a new tab) and the OP Sepolia (opens in a new tab). Etherscan has lots of tools to help you debug transactions.

Optimistic Etherscan has all the tools you expect from Etherscan, such as:

It's also got some OP-Mainnet-specific features:

Once Upon

If you're building on multiple chains, Once Upon's Superchain block explorer (opens in a new tab) consolidates transaction data across all OP Chains, offering developers a unified view of all Superchain activity, including testnets.

Once Upon currently supports:

  • Mainnet - Ethereum, OP Mainnet, Base, Zora, Public Goods Network
  • Sepolia - Ethereum, OP Sepolia, Base, Zora, Public Goods Network, Lyra, Mode

Access to Pre-Regenesis History

Because of our final regenesis on 11 November 2021, older transactions are not part of the current blockchain and do not appear on Etherscan (opens in a new tab). However, you can access transaction history between 23 June 2021 and the final regenesis using a number of different tools. For detailed instructions, see Regenesis History.

Inclusion Criteria

Developer teams who want to feature products/tools on this page must meet the following criteria:

  1. ongoing partnership with Optimism whether formal agreement, RPGF, RFP, collaborated on specific initiatives, etc.;
  2. established user base and OP ecosystem engagement such as governance participation, homegrown TG or Discord participation, etc.; and
  3. actively maintained developer tool that aligns with OP's commitment to a magical developer experience (e.g., easy-to-use, easy-to-integrate, great DevX, highly-rated by community, etc.)

For teams that are supporting but still establishing a user base, we encourage you to share your tool on the community block explorers page (opens in a new tab). You can also promote your tool in the developer forum (opens in a new tab) and signup to share your tool at the next demo day (opens in a new tab).

Next Steps