nautechsystems/nautilus_trader · error

Missing environment variable: {key_env}

Error message

Missing environment variable: {key_env}

What it means

with_credentials resolves the API key from the provided value or from the environment variable named by credential_env_vars(environment). When neither the explicit api_key argument nor the environment variable (e.g. DERIBIT_TESTNET_API_KEY or DERIBIT_API_KEY) is set, the builder cannot create an authenticated WebSocket client and fails fast.

Source

Thrown at crates/adapters/deribit/src/websocket/client.rs:310

    /// to the environment variable for the given `environment`:
    /// - Testnet: `DERIBIT_TESTNET_API_KEY` and `DERIBIT_TESTNET_API_SECRET`
    /// - Mainnet: `DERIBIT_API_KEY` and `DERIBIT_API_SECRET`
    ///
    /// # Errors
    ///
    /// Returns an error if neither the argument nor the environment variable
    /// provides a credential.
    pub fn with_credentials(
        environment: DeribitEnvironment,
        api_key: Option<String>,
        api_secret: Option<String>,
        auth_timeout_secs: Option<u64>,
        proxy_url: Option<String>,
    ) -> anyhow::Result<Self> {
        let (key_env, secret_env) = credential_env_vars(environment);

        let api_key = get_or_env_var_opt(api_key, key_env)
            .ok_or_else(|| anyhow::anyhow!("Missing environment variable: {key_env}"))?;
        let api_secret = get_or_env_var_opt(api_secret, secret_env)
            .ok_or_else(|| anyhow::anyhow!("Missing environment variable: {secret_env}"))?;

        Self::new(
            None,
            Some(api_key),
            Some(api_secret),
            DERIBIT_WS_HEARTBEAT_SECS,
            auth_timeout_secs,
            environment,
            TransportBackend::default(),
            proxy_url,
        )
    }

    /// Returns the current connection mode.
    fn connection_mode(&self) -> ConnectionMode {
        let mode_u8 = self.connection_mode.load().load(Ordering::Relaxed);

View on GitHub (pinned to 18893faf8b)

Solutions

1. Export the required environment variable (e.g. `export DERIBIT_API_KEY=...` for mainnet or the testnet equivalent) before starting the process.
2. Pass the api_key explicitly as the first argument to with_credentials.
3. Check which environment is configured so you set the matching variable (testnet vs mainnet naming).

Example fix

// before
let client = DeribitWebSocketClient::with_credentials(None, None, None, environment, ...).await?;
// after
let key = std::env::var("DERIBIT_API_KEY")?; // or pass Some(key)
let client = DeribitWebSocketClient::with_credentials(Some(key), None, None, environment, ...).await?;

// Rust: fail fast before constructing the client
let key = std::env::var("DERIBIT_API_KEY")
    .map_err(|_| anyhow!("set DERIBIT_API_KEY (or pass api_key) before connecting"))?;

fn credential_env_present(environment: Environment) -> bool {
    let (key_env, _) = credential_env_vars(environment);
    std::env::var(key_env).is_ok()
}

let client = match DeribitWebSocketClient::with_credentials(None, None, None, env, ...).await {
    Ok(c) => c,
    Err(e) if e.to_string().contains("Missing environment variable") => {
        return Err(anyhow!("configure {}", e))
    }
    Err(e) => return Err(e),
};

When it happens

Trigger: Calling DeribitWebSocketClient::with_credentials without passing api_key and without exporting the environment-specific key variable before process start.

Common situations: Forgetting to source a .env file, running in a container/CI where the secret was not injected, using the wrong environment variant (testnet var set but production client requested), or a typo in the variable name.

Understand the failure class

Background: "environment variable is not set" and "Missing keys in environment" errors: what missing required env var messages mean and how to fix them — this error's family across 28 libraries.

Related errors

• Missing environment variable: {secret_env}
• Redis config error: username supplied without password. Eith
• {secret_var} is required when {key_var} is provided
• {key_var} is required when {secret_var} is provided
• Both `api_key` and `api_secret` must be provided together

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/0e143cb6abeb1c68. Report an issue: GitHub.