tauri-apps/tauri · error

invalid webview URL

Error message

invalid webview URL

What it means

While servicing a `WebviewMessage::Url` request (used by APIs that read the current webview URL), the runtime calls `webview.url()` and parses the returned string into a `Url`. If the parse fails, `expect` panics with this message instead of returning the `FailedToSendMessage` error.

Solutions

1. Wait for the page load event (e.g. `on_page_load` / navigation completion) before reading the URL.
2. Ensure the webview was created with a valid absolute URL (with scheme).
3. If reproducible, file a Tauri issue — the runtime should degrade to an error, not panic.

Example fix

// before
let url = webview.url().unwrap();

// after
webview.on_page_load(|_, _| {
  let url = webview.url();
});

// validate before reading
let raw = webview.url().map_err(|_| ...)?;
if url::Url::parse(&raw).is_err() { /* defer until page loaded */ }

fn is_valid_url(s: &str) -> bool { url::Url::parse(s).is_ok() }

// if wrapping the runtime call
let result = std::panic::catch_unwind(|| webview.url());

When it happens

Trigger: Calling URL-reading APIs (`webview.url()`, getters that send `WebviewMessage::Url`) while the webview reports a URL string that is not a valid absolute URL — e.g. about:blank-like empty locations, non-standard scheme responses, or a webview that has not completed its initial navigation.

Common situations: Polling `webview.url()` immediately after creation before navigation finishes; pages loaded via unusual custom protocols; platform quirks returning a bare string without scheme.

Understand the failure class

Background: "Invalid URL" errors: why new URL(), URI.parse, and reqwest::Url reject your string — missing scheme, whitespace, and bad path format — this error's family across 39 libraries.

Related errors

• failed to run on_webview_created hook
• invalid IPC request URL
• not implemented
• not implemented
• poisoned WebContext store

AI-assisted analysis of tauri-apps/tauri@460ec35447 (2026-09-18). Data as JSON: /api/errors/2a89557c32afffb3. Report an issue: GitHub.

Appendix: source

Thrown at crates/tauri-runtime-wry/src/lib.rs:3795

          }
          WebviewMessage::SetBackgroundColor(color) => {
            if let Err(e) =
              webview.set_background_color(color.map(Into::into).unwrap_or((255, 255, 255, 255)))
            {
              log::error!("failed to set webview background color: {e}");
            }
          }
          WebviewMessage::ClearAllBrowsingData => {
            if let Err(e) = webview.clear_all_browsing_data() {
              log::error!("failed to clear webview browsing data: {e}");
            }
          }
          // Getters
          WebviewMessage::Url(tx) => {
            tx.send(
              webview
                .url()
                .map(|u| u.parse().expect("invalid webview URL"))
                .map_err(|_| Error::FailedToSendMessage),
            )
            .unwrap();
          }

          WebviewMessage::Cookies(tx) => {
            tx.send(webview.cookies().map_err(|_| Error::FailedToSendMessage))
              .unwrap();
          }

          WebviewMessage::SetCookie(cookie) => {
            if let Err(e) = webview.set_cookie(&cookie) {
              log::error!("failed to set webview cookie: {e}");
            }
          }

          WebviewMessage::DeleteCookie(cookie) => {
            if let Err(e) = webview.delete_cookie(&cookie) {

View on GitHub (pinned to 460ec35447)