nautechsystems/nautilus_trader · error

Native currency not specified for chain {}

Error message

Native currency not specified for chain {}

What it means

Blockchain::native_currency() panics when called on a blockchain variant that has no hard-coded native currency code/name mapping in the library. The match arm falls through to a catch-all panic for chains the crate has not been extended to support, so the error indicates the library lacks metadata for that chain rather than a caller mistake in values. It is a deliberate fail-fast instead of returning a bogus currency.

Source

Thrown at crates/model/src/defi/chain.rs:209

            // Ethereum and Ethereum testnets
            Blockchain::Ethereum | Blockchain::Sepolia | Blockchain::Holesky => ("ETH", "Ethereum"),

            // Ethereum L2s that use ETH
            Blockchain::Arbitrum
            | Blockchain::ArbitrumNova
            | Blockchain::ArbitrumSepolia
            | Blockchain::Base
            | Blockchain::BaseSepolia
            | Blockchain::Optimism
            | Blockchain::OptimismSepolia
            | Blockchain::Blast
            | Blockchain::BlastSepolia
            | Blockchain::Scroll
            | Blockchain::Linea => ("ETH", "Ethereum"),
            Blockchain::Polygon | Blockchain::PolygonAmoy => ("POL", "Polygon"),
            Blockchain::Avalanche | Blockchain::Fuji => ("AVAX", "Avalanche"),
            Blockchain::Bsc | Blockchain::BscTestnet => ("BNB", "Binance Coin"),
            _ => panic!("Native currency not specified for chain {}", self.name),
        };

        Currency::new(
            code,
            self.native_currency_decimals,
            0,
            name,
            CurrencyType::Crypto,
        )
    }

    /// Returns a reference to the `Chain` corresponding to the given `chain_id`, or `None` if it is not found.
    #[must_use]
    pub fn from_chain_id(chain_id: u32) -> Option<&'static Self> {
        match chain_id {
            2741 => Some(&chains::ABSTRACT),
            42161 => Some(&chains::ARBITRUM),
            42170 => Some(&chains::ARBITRUM_NOVA),

View on GitHub (pinned to 18893faf8b)

Solutions

1. Use a Blockchain variant that has a native currency mapping (ETH chains, Polygon, Avalanche, BSC, etc.)
2. Check the match in crates/model/src/defi/chain.rs and add an arm for your chain, or upgrade nautilus_model to a version that supports the chain
3. Wrap in catch_unwind or use a chain->currency mapping of your own before calling native_currency() for unsupported chains

Example fix

// before
let currency = chain.native_currency(); // panics for unsupported chain
// after
if let Ok(currency) = std::panic::catch_unwind(|| chain.native_currency()) {
    // use currency
} else {
    // supply fallback or reject the chain
}

// Only call native_currency() on supported chains
const SUPPORTED: &[Blockchain] = &[Blockchain::Ethereum, Blockchain::Arbitrum, Blockchain::Base, Blockchain::Optimism, Blockchain::Polygon, Blockchain::Avalanche, Blockchain::Bsc];
fn native_currency_safe(chain: Blockchain) -> Option<Currency> {
    if SUPPORTED.contains(&chain) { Some(chain.native_currency()) } else { None }
}

fn has_native_currency(chain: Blockchain) -> bool {
    !matches!(chain, Blockchain::Unknown) // extend with the unsupported set
}

let currency = std::panic::catch_unwind(|| chain.native_currency())
    .ok()
    .and_then(|c| c.ok()) // adapt to your fallback

When it happens

Trigger: Calling native_currency() on a Blockchain variant not covered by the match arms (e.g. an exotic or newly added chain like Blockchain::Unknown or a chain added by a newer version without a native currency entry). Also occurs indirectly when constructing instruments or data for such a chain.

Common situations: Connecting to an unsupported testnet or L2; a version upgrade introduced a new Blockchain variant used in config before model metadata was updated; building a custom chain enum value and expecting dynamic lookup.

Related errors

• Must have the `chain` field set
• `InstrumentId` not applicable to `Block`
• Invalid factory address for DEX {name} on chain {chain} for
• Liquidity addition overflow: x={current}, y={y}, delta={delt
• Liquidity subtraction underflow: x={current}, y={y}, delta={

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/b85697b4b973ad96. Report an issue: GitHub.