gofiber/fiber · error

failed to render

Error message

failed to render: %w

What it means

Returned by DefaultRes.Render() when a configured Views engine (the github.com/gofiber/template family) fails its Render call. Fiber wraps the engine error with 'failed to render' so the call site is identifiable; the underlying %w carries the engine-specific cause. The RLock held on the views lock is released via defer before the error propagates.

Solutions

1. Check the wrapped error (errors.Unwrap) for the engine-specific message — it names the missing template or the parse line.
2. Ensure Views.Load() is called and returns nil before the server starts; verify the templates root path is correct.
3. Confirm every layout name passed to Render() (and the global ViewsLayout) exists as a registered template.
4. If using an embed.FS, verify the //go:embed directive includes every .tmpl/.hbs file the engine references.
5. Pin gofiber/template/<engine> to a version compatible with your fiber/v3 minor.

Example fix

// before: template path wrong, engine cannot find it
app := fiber.New(fiber.Config{
    Views: html.New("./views", ".html"), // actual dir is ./templates
})
app.Get("/", func(c fiber.Ctx) error {
    return c.Render("index", fiber.Map{}) // failed to render: ...
})

// after
app := fiber.New(fiber.Config{
    Views: html.New("./templates", ".html"),
})
if err := app.Config().Views.Load(); err != nil {
    log.Fatal(err)
}

// Validate the engine and templates before serving traffic.
if app.Config().Views != nil {
    if err := app.Config().Views.Load(); err != nil {
        log.Fatal("views load failed: ", err)
    }
}
// Smoke-render critical templates at startup.
probe := new(bytes.Buffer)
if err := app.Config().Views.Render(probe, "index", fiber.Map{}); err != nil {
    log.Fatal("smoke render failed: ", err)
}

// In the handler: distinguish render errors from other failures.
if err := c.Render(name, bind); err != nil {
    var fe *fiber.Error
    if errors.As(err, &fe) {
        return err // pass through fiber errors
    }
    log.Printf("render %q failed: %v", name, err)
    return fiber.ErrInternalServerError
}

When it happens

Trigger: Calling ctx.Render(name, bind) or res.Render(name, bind) where app.config.Views is non-nil, and the engine's Render() returns an error: template file not loaded/registered, template syntax error, missing partial/layout referenced in ViewsLayout, or a binding type the engine rejects.

Common situations: Forgot to call Views.Load() or the engine failed to find the template directory; template filename typo; layout referenced in Config.ViewsLayout does not exist; version mismatch between fiber/v3 and a gofiber/template engine whose Render signature changed; passing a bind struct whose fields/methods the template references incorrectly.

Related errors

• fiber: no view engine configured
• failed to execute
• failed to parse
• fiber: failed to reload views

AI-assisted analysis of gofiber/fiber@a105acad6c (2026-08-11). Data as JSON: /api/errors/8b5d77ae66664e8a. Report an issue: GitHub.

Appendix: source

Thrown at res.go:921

	var rendered bool
	for _, prefix := range slices.Backward(rootApp.mountFields.appListKeys) {
		app := rootApp.mountFields.appList[prefix]
		if prefix == "" || strings.Contains(r.c.OriginalURL(), prefix) {
			if len(layouts) == 0 && app.config.ViewsLayout != "" {
				layouts = []string{
					app.config.ViewsLayout,
				}
			}

			// Render template from Views
			if app.config.Views != nil {
				if err := func() error {
					viewsLock := getViewsLock(app.config.Views)
					viewsLock.RLock()
					defer viewsLock.RUnlock()

					if err := app.config.Views.Render(buf, name, bind, layouts...); err != nil {
						return fmt.Errorf("failed to render: %w", err)
					}

					return nil
				}(); err != nil {
					return err
				}

				rendered = true
				break
			}
		}
	}

	if !rendered {
		// Render raw template using 'name' as filepath if no engine is set
		var tmpl *template.Template
		if _, err := readContent(buf, name); err != nil {
			return err

View on GitHub (pinned to a105acad6c)