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Reactive Smart Contracts Image

Overview​

Reactive smart contracts (RSCs) operate on a standard Ethereum Virtual Machine (EVM) and can be written in any EVM-compatible language, with Application Binary Interfaces (ABIs) particularly customized for Solidity. Their unique capabilities stem from reactive nodes and a specialized pre-deployed system contract.

Key Features​

Reactive Smart Contracts (RSCs) monitor blockchains for specific events and respond automatically, unlike traditional contracts that rely on EOAs to trigger actions. This reactivity and their use of Inversion of Control (IoC) — where contracts decide when to act — set them apart.

RSCs define which blockchains, contracts, and events to watch. When a relevant event occurs, they execute logic, update state, and perform trustless transactions within the Reactive Network.

Deployment​

RSCs deploy to both the main Reactive Network and a private ReactVM. The main copy interacts with EOAs and manages subscriptions via the system contract. The ReactVM copy handles event processing but is not accessible to EOAs.

State and Separation​

The two copies are isolated and don’t share state. Since they use the same bytecode, use constructor flags or checks to distinguish the environment. You can detect if a contract is on ReactVM by calling the system contract — calls will revert outside ReactVMs. See examples for details.

ReactVM Limitations​

In ReactVM, RSCs can’t access external systems directly. They receive logs from the Reactive Network and can call destination chain contracts but nothing else.

Contract Verification​

Contracts can be verified either after or during deployment with the Sourcify endpoint. Sourcify is a decentralized verification service that stores and verifies source code for smart contracts. It allows anyone to match deployed bytecode with human-readable source code, making smart contracts auditable and transparent.

Reactive Sourcify Endpoint: https://sourcify.rnk.dev/

Verify After Deployment​

For contract verification after deployment, run the following command:

forge verify-contract \
--verifier sourcify \
--verifier-url https://sourcify.rnk.dev/ \
--chain-id $CHAIN_ID \
$CONTRACT_ADDR $CONTRACT_NAME

Replace:

  • $CHAIN_ID with 1597 for Reactive Mainnet and 5318008 for Kopli Testnet
  • $CONTRACT_ADDR with your deployed contract’s address
  • $CONTRACT_NAME with the name of the contract (e.g., MyContract)

Verify on Deployment​

You can also verify the contract during deployment by appending the relevant flags to forge create. The following command submits your contract source to Sourcify right after deployment:

forge create \
--verifier sourcify \
--verifier-url https://sourcify.rnk.dev/ \
--verify \
--chain-id $CHAIN_ID \
--private-key $PRIVATE_KEY \
$PATH

Replace:

  • $CHAIN_ID with 1597 for Reactive Mainnet and 5318008 for Kopli Testnet
  • $PATH with something like src/MyContract.sol:MyContract
  • $PRIVATE_KEY with your signer’s private key

An example of verifying on deployment could look like so:

forge create \
  --legacy \
  --broadcast \
  --rpc-url $REACTIVE_RPC_URL \
  --private-key $REACTIVE_PRIVATE_KEY \
  --chain-id $REACTIVE_CHAIN_ID \
  --value 0.01ether \
  --verify \
  --verifier sourcify \
  --verifier-url https://sourcify.rnk.dev/ \
  src/.../MyContract.sol:MyContract \
  --constructor-args \
    $ARGUMENT_1 \
    $ARGUMENT_2 \
    $ARGUMENT_3 \
    # ...add more as needed
Broadcast Error

If you encounter the error described below, it means your Foundry version (or local setup) does not expect the --broadcast flag for forge create. Simply remove --broadcast from your command and re-run it.

error: unexpected argument '--broadcast' found

Verified Contracts on Reactscan​

Reactive Block Explorers: Mainnet and Kopli Testnet.

After verification, go to the relevant Reactscan. While in your RVM, navigate to Contracts and click the required contract address.

Image a

Open the “Contract” tab.

Image b

If successful, you’ll see the following:

Contract Address: 0xc3e185561D2a8b04F0Fcd104A562f460D6cC503c
Status: VERIFIED (EXACT MATCH)
Compiler: 0.8.28

Image c

The source code will be publicly viewable, with full syntax highlighting and structure, helping others understand and trust the contract logic.

More on Reactive Smart Contracts →