BerriAI/litellm · error

failed to bind listener

Error message

failed to bind listener

What it means

Error "failed to bind listener" thrown in BerriAI/litellm.

Source

Thrown at litellm-rust/crates/ai-gateway/src/main.rs:82

    } else {
        eprintln!(
            "realtime connection pool disabled (REALTIME_POOL_SIZE=0); fresh-dialing each connect"
        );
    }

    let state = AppState {
        router,
        master_key,
        loggers: Arc::new(loggers),
        realtime_pool,
    };

    let host = std::env::var("HOST").unwrap_or_else(|_| DEFAULT_HOST.to_string());
    let port = resolve_port();

    let listener = tokio::net::TcpListener::bind((host.as_str(), port))
        .await
        .expect("failed to bind listener");
    eprintln!("litellm-ai-gateway listening on {host}:{port}");
    axum::serve(listener, routes::app(state))
        .await
        .expect("server error");
}

/// Register every deployment's upstream key with the pool so the replenisher
/// pre-warms it. Mirrors `service::run`'s key derivation (strip `openai/`, resolve
/// api_key); deployments whose key can't be resolved are skipped (they fresh-dial
/// and surface the auth error on the request path, as before).
fn register_deployments(router: &Router, pool: &RealtimePool) {
    for deployment in router.deployments() {
        let params = &deployment.litellm_params;
        let provider_model = params
            .model
            .strip_prefix("openai/")
            .unwrap_or(&params.model);
        if let Some(key) = upstream_key(

View on GitHub (pinned to 77b7c6c40c)

Solutions

1. Verify the bind address/port is free (not already in use) and the process has permission to bind it.
2. Change the listen address/port in configuration if it conflicts.

When it happens

Trigger: Thrown at litellm-rust/crates/ai-gateway/src/main.rs:82 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of BerriAI/litellm@77b7c6c40c (2026-08-18). Data as JSON: /api/errors/4c50c980a7a57ee7. Report an issue: GitHub.