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FSCO Docs

Chain

Overview

Section titled “Overview”

The Chain module provides a raw, low-level interface to the blockchain. It allows you to execute arbitrary transactions and simulate method calls using RLP-encoded data — without needing to register ABIs or deployments. This is ideal for advanced users who need full control over the transaction payload.

Key Features

Section titled “Key Features”
  • Raw Transaction Execution: Send any signed or unsigned EVM-compatible transaction to the blockchain
  • Method Call Simulation: Perform read-only method calls with raw calldata
  • Transaction Retrieval: Fetch detailed information about transactions by hash or FSCO-issued transaction ID
  • Wallet Integration: Seamlessly use FSCO wallet IDs to sign and broadcast transactions
  • Multi-Chain Support: Fully supports all EVM-compatible networks

Core Concepts

Section titled “Core Concepts”

Chain Execution (/execute)

Section titled “Chain Execution (/execute)”
  • Used for state-changing transactions (e.g. sending tokens, calling transfer)
  • Requires full RLP-encoded transaction data (txData)
  • Signed by an FSCO wallet and broadcast to the specified chainId
  • Returns a queryId to reference the transaction later

Chain Call (/call)

Section titled “Chain Call (/call)”
  • Simulates a read-only method (e.g. balanceOf, ownerOf)
  • Does not incur gas or change state
  • Uses txData, similar to execution, but only for querying
  • Returns a decoded data field with the method’s result

Get Transaction by Hash

Section titled “Get Transaction by Hash”
  • Look up any blockchain transaction using its txHash and chainId
  • Returns full block, gas, status, logs, and decoded return data

Get Transaction by FSCO ID

Section titled “Get Transaction by FSCO ID”
  • If you executed a transaction using FSCO, you can use the queryId returned to fetch its status and metadata

When to Use This Module

Section titled “When to Use This Module”

Use the Chain module when:

  • You want to bypass ABI registration and work directly with low-level data
  • You have custom or dynamic contracts and don’t want to manage deployments
  • You want to simulate a call without persisting any state
  • You want to broadcast pre-signed transactions
  • You’re implementing advanced tooling, like wallets or SDKs

How It Works

Section titled “How It Works”

Executing a Transaction

Section titled “Executing a Transaction”
  1. Encode your transaction calldata
  2. Provide txData, walletId, and chainId to /v2/chain/execute
  3. FSCO signs and broadcasts the transaction
  4. You’ll receive a queryId to check its status later

Performing a Call

Section titled “Performing a Call”
  1. Encode your read-only method calldata
  2. Submit txData and chainId to /v2/chain/call
  3. FSCO returns the decoded result in the data field

Retrieving Transactions

Section titled “Retrieving Transactions”
  • Use GET /v2/chain/tx/{txId} for FSCO-issued transactions
  • Use GET /v2/chain/chain/{chainId}/tx/{txHash} for blockchain-native lookups

Common Use Cases

Section titled “Common Use Cases”
  • Power users building SDKs with full control over calldata
  • Wallets broadcasting signed transactions
  • Gasless reads from contracts without registering ABIs
  • Debugging on-chain interactions by inspecting raw return data and logs

Getting Started

Section titled “Getting Started”
  1. Execute a Chain Transaction
  2. Call a Chain Method
  3. Get Transaction by FSCO ID
  4. Get Transaction by Hash

API Reference

Section titled “API Reference”

For full request/response schemas, see the Chain API Reference

Best Practices

Section titled “Best Practices”
  • Use transaction simulation before executing costly operations
  • Always store returned queryId values to track transaction status
  • Use a reliable encoder (e.g. ethers.js or viem) to produce txData
  • Ensure wallet IDs used are funded and correctly scoped to your org

Limitations

Section titled “Limitations”
  • Requires correctly encoded RLP data; FSCO does not validate ABI-level structure
  • No built-in decoding of logs or method outputs — returned data is raw
  • Transaction execution depends on network availability and wallet funding