nautechsystems/nautilus_trader · error

Invalid chain '{chain_name}' in venue '{venue_str}'

Error message

Invalid chain '{chain_name}' in venue '{venue_str}'

What it means

Venue::parse_dex expects a DEX venue string in 'Chain:DexId' format and validates the chain part against known chains via Chain::from_chain_name. If the text before the colon is not a recognized chain name, this error is raised.

Source

Thrown at crates/model/src/identifiers/venue.rs:156

    }

    #[cfg(feature = "defi")]
    /// Parses a venue string to extract blockchain and DEX type information.
    ///
    /// # Errors
    ///
    /// Returns an error if:
    /// - The venue string is not in the format "chain:dex"
    /// - The chain name is not recognized
    /// - The DEX name is not recognized
    pub fn parse_dex(&self) -> anyhow::Result<(Blockchain, DexType)> {
        let venue_str = self.as_str();
        let Some((chain_name, dex_id)) = venue_str.split_once(':') else {
            anyhow::bail!("Venue '{venue_str}' is not a DEX venue (expected format 'Chain:DexId')")
        };

        let chain = Chain::from_chain_name(chain_name).ok_or_else(|| {
            anyhow::anyhow!("Invalid chain '{chain_name}' in venue '{venue_str}'")
        })?;
        let dex_type = DexType::from_dex_name(dex_id)
            .ok_or_else(|| anyhow::anyhow!("Invalid DEX '{dex_id}' in venue '{venue_str}'"))?;

        Ok((chain.name, dex_type))
    }
}

impl Debug for Venue {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "\"{}\"", self.0)
    }
}

impl Display for Venue {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.0)
    }

View on GitHub (pinned to 18893faf8b)

Solutions

1. Use the exact canonical chain name recognized by Chain::from_chain_name (check casing, e.g. 'Ethereum', 'Solana', 'Arbitrum').
2. Verify the chain is registered/compiled into the build; register or add the chain if it is a supported-but-missing one.
3. Log/inspect the full venue string to confirm the prefix before the ':' is the chain and the suffix is the DEX.

Example fix

// before
let (chain, dex) = Venue::from("ETHEREUM:uniswap").parse_dex()?;
// after
let (chain, dex) = Venue::from("Ethereum:uniswap").parse_dex()?;

let (chain_name, _) = venue_str.split_once(':')?;
if Chain::from_chain_name(chain_name).is_none() {
    return Err(format!("unknown chain {chain_name}"));
}

// Rust
let (chain, dex) = venue.parse_dex().map_err(|e| ConfigError::BadDexVenue(e.to_string()))?;

When it happens

Trigger: Calling parse_dex on a venue whose prefix is not a registered chain name, e.g. "ETHEREUM:uniswap" when the chain registry uses "Ethereum", or a completely unknown chain like "SOLANAMAINNET:raydium".

Common situations: Configuring a DeFi venue by hand with wrong casing for the chain, using a chain the installation does not know, or forgetting that parse_dex only accepts venues that actually contain a ':' separator (well-formed DEX strings but bogus chain names).

Understand the failure class

Background: "invalid id" errors: invalid identifier format — why libraries reject IDs before lookup, and how to fix them — this error's family across 37 libraries.

Related errors

• Invalid DEX '{dex_id}' in venue '{venue_str}'
• Unknown DEX {dex_id} on chain {}
• Dex {dex_id} doesn't exist for chain {}
• Unknown venue code: {code}
• Invalid venue {}, expected Blockchain DEX format

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/601e13f9ab6f6ad3. Report an issue: GitHub.