What does a stable, production-grade Selenium suite look like?

Stability is a design outcome, not a library setting. The suite should be small enough to trust, fast enough to run on every change, and structured so a failure points to a specific behaviour. Everything else is secondary.

public class CheckoutTest extends BaseTest {
    @Test
    public void customerCanPlaceAnOrder() {
        User user = TestData.newUser();
        Cart cart = ApiClient.createCart(user, "SKU-1", 2);

        new CheckoutPage(driver())
            .openFor(cart)
            .payWith("4242424242424242")
            .submit();

        WebDriverWait wait = new WebDriverWait(driver(), Duration.ofSeconds(15));
        wait.until(ExpectedConditions.urlContains("/confirmation"));

        Assert.assertTrue(new ConfirmationPage(driver()).hasOrderNumber());
    }
}

• Test user journeys and integration boundaries, not every field validation
• Use stable test ids and intention-revealing page objects
• Wait for observable state with explicit waits and no fixed sleeps
• Isolate driver, data and files per test so order and parallelism do not matter
• Run a fast critical-path suite on every change and a broader matrix on a schedule
• Attach evidence on failure and publish reports from CI
• Track runtime, flake rate and failure ownership instead of only pass percentage
• Delete or quarantine tests that no longer provide a trustworthy signal

The hard trade-off is coverage versus trust. A suite of two hundred UI tests that fails randomly is worse than twenty reliable journeys plus strong API and unit coverage. Push checks down the pyramid, keep the browser for what only a browser can prove, and be explicit about which risks the remaining suite covers.