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Indexing on Fuel Network

Introduction​

Envio supports the Fuel Network on mainnet and testnet. This page shows how to use HyperIndex with Fuel’s architecture and features.

Fuel offers several advantages as a modular execution layer including:

  • Parallel transaction execution
  • State-minimized design
  • UTXO-based architecture
  • Advanced FuelVM capabilities

HyperIndex for Fuel​

HyperIndex enables developers to easily index and query real-time and historical data on Fuel Network with the same powerful features available for EVM chains.

Getting Started with Fuel Indexing​

You can start indexing Fuel contracts in two ways:

  1. Quick Start (5-minute tutorial): Follow our step-by-step tutorial to create your first Fuel indexer quickly.

  2. No-Code Contract Import: Use our Contract Import tool to automatically generate configuration and schema files for your Fuel contracts.

Example Fuel Indexers​

Looking for inspiration? Check out these indexers built by projects in the Fuel ecosystem:

ProjectTypeGitHub Repository
SparkOrderbook DEXgithub
MiraAMM DEXgithub
ThunderNFT Marketplacegithub
SwaylendLending Protocolgithub
GreeterTutorialgithub

Features Supported on Fuel​

HyperIndex for Fuel supports all the core features available in the EVM version:

Fuel-Specific Event Types​

Understanding Fuel's Event Model​

Fuel's event model differs significantly from EVM. Instead of predefined events, Fuel uses a more flexible approach with various receipt types that can be indexed.

LOG_DATA Receipts (Primary Event Type)​

The most common event type in Fuel is the LOG_DATA receipt, created by the log instruction in Sway contracts.

Unlike Solidity's emit which requires predefined event structures, Sway's log function allows passing any data, providing greater flexibility.

Configuration Example:​

ecosystem: fuel
network:
  name: "fuel_testnet"

contracts:
  - name: SwayContract
    abi_file_path: "./abis/SwayContract.json"
    start_block: 1
    address: "0x123..."
    events:
      - name: NewGreeting
        logId: "8500535089865083573"

The logId is a unique identifier for the logged struct, which you can find in your contract's ABI file.

Auto-detection of logId:​

If your event name matches the logged struct name in Sway, you can omit the logId:

events:
  - name: NewGreeting # Will automatically detect logId if it matches the struct name

Tip: Instead of manually configuring events, use the Contract Import tool which automatically detects events and generates the proper configuration.

Additional Fuel Event Types​

Fuel allows indexing several additional receipt types not available in EVM:

Event TypeDescriptionExample Configuration
MintTriggered when a contract mints tokens- name: Mint
BurnTriggered when a contract burns tokens- name: Burn
TransferCombines TRANSFER and TRANSFER_OUT receipts- name: Transfer
CallTriggered when a contract calls another contract- name: Call

Using Custom Names:​

You can rename these events while maintaining their type:

events:
  - name: MintMyNft # Custom name
    type: mint # Actual event type

Note: All event types can be used with Wildcard Indexing.

Transfer Event Specifics​

The Transfer event type combines two Fuel receipt types:

  • TRANSFER: Emitted when a contract transfers tokens to another contract
  • TRANSFER_OUT: Emitted when a contract transfers tokens to a wallet

Important: Transfers between wallets are not included in the Transfer event type.

Event Object Structure in Handlers​

When handling Fuel events, the event object structure differs from EVM:

// Example Fuel event handler
SwayContract.NewGreeting.handler(async ({ event, context }) => {
  // Access event parameters
  const message = event.params.message;

  // Access block information
  const blockHeight = event.block.height;
  const blockTime = event.block.time;
  const blockId = event.block.id;

  // Access transaction information
  const txId = event.transaction.id;

  // Access source contract address
  const sourceContract = event.srcAddress;

  // Access log position
  const logIndex = event.logIndex;

  // Store data
  context.Greeting.set({
    id: event.transaction.id,
    message: message,
    timestamp: blockTime,
  });
});

HyperFuel​

HyperFuel is Envio's low-level data API for the Fuel Network (equivalent to HyperSync for EVM chains).

HyperFuel provides:

  • High-performance data access
  • Flexible query capabilities
  • Multiple data formats (Parquet, Arrow, typed data)
  • Complete historical data

Available Clients​

Access HyperFuel data using any of these clients:

HyperFuel Endpoints​

For detailed information, see the HyperFuel documentation.

About Fuel Network​

Fuel is an operating system purpose-built for Ethereum rollups with unique architecture focused on:

  • Parallelization: Execute transactions concurrently for higher throughput
  • State-minimized execution: Efficient storage and computation model
  • Interoperability: Seamless integration with other blockchain systems

Powered by the FuelVM, Fuel expands Ethereum's capabilities without compromising security or decentralization.

Resources​

Need Help?​

If you encounter any issues with Fuel indexing, please:

  1. Check our Troubleshooting guides
  2. Join our Discord for community support
  3. Create an issue in our GitHub repository