tauri-apps/tauri · error

beforeDevCommand `{}` failed with exit code {}

Error message

beforeDevCommand `{}` failed with exit code {}

What it means

When `beforeDevCommand` is configured in object form with `"wait": true`, `tauri dev` runs the script through `sh -c` (or `cmd /S /C` on Windows) in the frontend dir and waits for it. A non-zero exit code aborts dev mode, because the frontend server the app depends on never came up correctly.

Source

Thrown at crates/tauri-cli/src/dev.rs:195

        let mut command = Command::new("sh");
        command
          .arg("-c")
          .arg(&before_dev)
          .current_dir(cwd)
          .envs(env);
        command
      };

      if wait {
        let status = command.piped().map_err(|error| Error::CommandFailed {
          command: format!(
            "`{before_dev}` with `{}`",
            if cfg!(windows) { "cmd /S /C" } else { "sh -c" }
          ),
          error,
        })?;
        if !status.success() {
          crate::error::bail!(
            "beforeDevCommand `{}` failed with exit code {}",
            before_dev,
            status.code().unwrap_or_default()
          );
        }
      } else {
        command.stdin(Stdio::piped());
        command.stdout(os_pipe::dup_stdout().unwrap());
        command.stderr(os_pipe::dup_stderr().unwrap());

        let child = SharedChild::spawn(&mut command)
          .unwrap_or_else(|_| panic!("failed to run `{before_dev}`"));

        let child = BEFORE_DEV.get_or_init(move || child);
        std::thread::spawn(move || {
          let status = child
            .wait()
            .expect("failed to wait on \"beforeDevCommand\"");

View on GitHub (pinned to 52e4b6e71d)

Solutions

1. Run the exact script manually in the frontend dir (e.g. `npm run dev`) and fix the underlying failure it reports
2. If dependencies are missing, install them (`npm install`) first
3. Check the script string for typos and that it matches a script defined in package.json; verify `wait: true` is what you want (string-form beforeDevCommand does not wait and would not raise this)

Example fix

// before (tauri.conf.json)
"beforeDevCommand": { "script": "npm run dev", "wait": true }  // npm run dev exits 1

// after: fix package.json so `npm run dev` succeeds
"scripts": { "dev": "vite" }

# prove the dev script works before wiring it into tauri.conf.json
cd frontend && npm ci && npm run dev &
DEV_PID=$!; sleep 5
kill $DEV_PID 2>/dev/null   # if it exited early, npm reports non-zero here

When it happens

Trigger: `tauri dev` with `"beforeDevCommand": { "script": "npm run dev", "wait": true }` where the script fails: missing devDependencies, a syntax error, an already-in-use port, or a typo'd script name. Only the `wait: true` object form surfaces the exit code; the plain string form spawns without waiting.

Common situations: Fresh clones where `npm install` was not run before `tauri dev`; scripts that fail only on some machines (port conflicts, missing env vars); switching package managers without updating the script string.

Related errors

• {} `{}` failed with exit code {}
• failed to run `{before_dev}`
• Couldn't recognize the {} folder as a Tauri project. It must
• No external IP detected.
• failed to read missing addr file {}: {e}

AI-assisted analysis of tauri-apps/tauri@52e4b6e71d (2026-08-20). Data as JSON: /api/errors/c08769ae800cee7c. Report an issue: GitHub.