Compatibility is the starting point
An EVM-compatible chain can run familiar contract code and clients while differing in transaction ordering, block-number semantics, gas accounting and settlement. Migrating from Ethereum or Base therefore needs more than a replacement RPC URL. Keep the source application's assumptions visible during the review.
Build a migration matrix
| Area | What to verify |
|---|---|
| Configuration | Chain ID, RPC, explorer, token and contract addresses |
| Contract logic | block.number, timestamps, randomness and L1 message senders |
| Submission | Nonce allocation, sequencer acceptance and fee model |
| Data ingestion | Block pace, log ranges, reconnect recovery and finality |
| Operations | Rate limits, authentication, supported tracing and historical state |
Base-specific OP Stack behavior should not be copied into an Arbitrum-derived Robinhood integration. Use the destination chain's documentation for each row.
Block fields change contract behavior
Robinhood documents the following EVM differences. Review the contract paths that read these fields, including imported libraries. Source: Differences from Ethereum.
| Field | Robinhood behavior | Developer action |
|---|---|---|
block.prevrandao / block.difficulty | Constant values, unsuitable for randomness. | Remove lottery, allocation or sampling logic that treats them as unpredictable. Select and validate a dedicated randomness oracle. |
block.coinbase | The network fee account. | Do not use it to identify or pay the current miner or validator. |
blockhash(n) | Reliable only for recent blocks; unsuitable for randomness. | Keep a separate history source for older hashes. |
The documentation does not specify a numeric constant for prevrandao/difficulty or a fee-account address here. EVM compatibility does not justify importing either value from another network.
Check deployed code and init code separately
Robinhood publishes a maximum contract code size of 96 KB and a maximum init code size of 192 KB. Source: Contract size limit. Keep those published units when recording the requirements.
Measure the creation payload and resulting runtime bytecode separately. A small deployed contract can still have large constructor logic or arguments. Record both artifact sizes with the compiler version and optimizer settings before choosing a deployment target.
A local environment configured for Ethereum can reject an artifact that fits Robinhood's published limit. Configure destination-specific limits or validate on Robinhood testnet. Do not treat an unlimited-size local setting as evidence that the production deployment fits. Keep deployment checks per network if the same build also targets Ethereum.
Authorize the aliased L1 contract caller
For an L1 contract message delivered to Robinhood through a retryable ticket, the L2 contract sees an aliased msg.sender: the L1 contract address plus a fixed offset. The official guide recommends the SDK's applyAlias and undoAlias helpers. Source: Cross-Chain Messaging, L1 to L2.
An access check against the unmodified L1 controller address will not recognize that caller. Derive the expected alias for the authorized L1 contract with the supported SDK, then test both an authorized cross-chain call and an unrelated caller that must fail. Keep a separate authorization path for direct L2 administration if the application needs it.
This rule concerns the documented L1-contract messaging path. Do not transform every wallet address or every direct L2 caller. The Robinhood guide does not print the numeric offset, so use its documented helper rather than a constant copied from another chain.
Run a targeted test set
- Deploy the reproducible build on Robinhood testnet using the destination configuration.
- Assert that no security or economic decision depends on prevrandao/difficulty being random, and that coinbase is not treated as a validator identity.
- Measure creation payload and runtime bytecode with the production build settings. Verify both against the destination limits.
- Exercise the actual L1-contract message route. Confirm that access control accepts the expected alias and rejects an unrelated caller.
- Exercise timeouts and block-based conditions while comparing L1 estimates with L2 heights. Test failed execution, socket reconnects and receipt reconciliation.
- Validate the exact token contracts and oracle interfaces your app uses.
Separate migration from product availability
A standard method in a library does not prove a provider exposes every debug or pending-transaction method. Read Supanode's Robinhood method list and restrictions before enabling features. Existing users and balances also do not move automatically with a contract redeployment. Plan any asset or state migration separately, with explicit acceptance evidence for source and destination.
Use the existing timing and fee guides
Keep detailed timing and budget tests in their own checklists: L1 estimates versus L2 block numbers, fees and transaction ordering, and Robinhood's finality model. A soft confirmation, a settled result and a completed cross-chain action serve different application decisions.