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

# Block explorers

> Learn about different block explorers you can use to interact with contracts and view transaction history for OP Mainnet and OP Sepolia.

## Blockscout

We have a Blockscout explorer for [OP Mainnet](https://optimism.blockscout.com) and [OP Sepolia](https://optimism-sepolia.blockscout.com/). It includes:

* [Verified testnet contract source code, along with the ability to interact with it](https://optimism.blockscout.com/verified-contracts)
* [Detailed testnet transaction information](https://optimism.blockscout.com/tx/0xa1b04233084d4067ec0bb3e09301012900f0e209f14a3d406f3d6dc696eea138)

Blockscout also has some OP-Mainnet-specific features:

* [An interactive list of deposits (L1-L2)](https://optimism.blockscout.com/l2-deposits)
* [An interactive list of withdrawals (L2-L1)](https://optimism.blockscout.com/l2-withdrawals)
* [Transaction batches](https://optimism.blockscout.com/l2-txn-batches)
* [App marketplace](https://optimism.blockscout.com/apps)
* And much more!

## Etherscan

We have Etherscan explorers for the [OP Mainnet](https://explorer.optimism.io) and the [OP Sepolia](https://testnet-explorer.optimism.io/).
Etherscan has lots of tools to help you debug transactions.

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

* [Verified contract source code, along with the ability to interact with it](https://explorer.optimism.io/address/0x420000000000000000000000000000000000000F#code)
* [Detailed transaction information](https://explorer.optimism.io/tx/0x292423266d6da24126dc4e0e81890c22a67295cc8b1a987e71ad84748511452f)
* And everything else you might find on Etherscan!

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

* [A list of L1-to-L2 transactions](https://explorer.optimism.io/txsEnqueued)
* [A list of L2-to-L1 transactions](https://explorer.optimism.io/txsExit)
* [A tool for finalizing L2-to-L1 transactions](https://explorer.optimism.io/messagerelayer)
* And more! Just check it out and click around to find all of the available features.

## Superscan by Routescan

[Superscan](https://superscan.network) is the dev-focused OP Stack explorer unified at the ecosystem level, powered by [Routescan](https://routescan.io). On the Superscan, developers can quickly glance at transactions, blocks, addresses, deployed contracts and more across OP Stack chains in unified pages.

The Superscan currently includes:

* Mainnet - OP Mainnet, Base, Zora, Mode, Cyber, Orderly, Fraxtal, Public Goods Network
* Testnet - Zora, Mode, Orderly, Fraxtal

## Tenderly

Tenderly's [Developer Explorer](https://docs.tenderly.co/developer-explorer?mtm_campaign=ext-docs\&mtm_kwd=optimism) for OP Mainnet and OP Sepolia allows you to monitor and inspect transactions, providing a high level of detail and additional tools:

Tenderly Developer Explorer lets you:

* Keep track of specific [contracts](https://docs.tenderly.co/developer-explorer/contracts?mtm_campaign=ext-docs\&mtm_kwd=optimism) and their transactions
* Inspect [transaction execution](https://docs.tenderly.co/developer-explorer/inspect-transaction?mtm_campaign=ext-docs\&mtm_kwd=optimism) with fully decoded transaction trace
* [Debug](https://docs.tenderly.co/debugger?mtm_campaign=ext-docs\&mtm_kwd=optimism) failing and [simulate](https://docs.tenderly.co/simulator-ui/using-simulation-ui?mtm_campaign=ext-docs\&mtm_kwd=optimism) correct transactions before sending them on-chain
* Evaluate [function-level gas usage](https://docs.tenderly.co/debugger/gas-profiler?mtm_campaign=ext-docs\&mtm_kwd=optimism) for any transaction
* Set up [Alerts](https://docs.tenderly.co/alerts/tutorials-and-quickstarts/alerting-quickstart-guide?mtm_campaign=ext-docs\&mtm_kwd=optimism) to monitor interactions, access control, asset transfers, and contracts' state changes
* Create a [Virtual TestNet](https://docs.tenderly.co/virtual-testnets?mtm_campaign=ext-docs\&mtm_kwd=optimism) from a specific OP Mainnet or OP Chain transaction for systematic research

## 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](https://explorer.optimism.io/?utm_source=op-docs\&utm_medium=docs).
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](/node-operators/guides/management/regenesis-history).

## Next Steps

* Looking for other developer tools? See [developer tools overview](/app-developers/tools) to explore more options!