gofiber/fiber · error

failed to parse: %w

Error message

failed to parse: %w

What it means

In Render's fallback path (used when no Views engine is configured), Fiber reads the file at 'name' and parses it with Go's html/template. This error means the file content has Go-template syntax errors: unclosed action, bad delimiter, or an unexpected token.

Source

Thrown at res.go:792

					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
		}
		// Parse template
		tmpl, err := template.New("").Parse(rootApp.toString(buf.Bytes()))
		if err != nil {
			return fmt.Errorf("failed to parse: %w", err)
		}
		buf.Reset()
		// Render template
		if err := tmpl.Execute(buf, bind); err != nil {
			return fmt.Errorf("failed to execute: %w", err)
		}
	}

	response := &r.c.fasthttp.Response

	// Set Content-Type to text/html
	response.Header.SetContentType(MIMETextHTMLCharsetUTF8)
	// Set rendered template to body
	response.SetBody(buf.Bytes())

	return nil
}

View on GitHub (pinned to 9a4c7e57fe)

Solutions

1. Fix the Go template syntax in the file (close actions, valid delimiters).
2. Alternatively, configure app.Config.Views with a gofiber/template engine for richer features and clearer errors.
3. Validate templates offline with text/template/html-template before deploying.

Example fix

// broken.tmpl:  <h1>{{ .Title </h1>   // unclosed action -> failed to parse
// fixed.tmpl:   <h1>{{ .Title }}</h1>

// validate a template file parses before serving
func templateParses(path string) error {
    b, err := os.ReadFile(path)
    if err != nil { return err }
    _, err = template.New("").Parse(string(b))
    return err
}

if err := c.Render(name, bind); err != nil {
    if strings.Contains(err.Error(), "failed to parse") {
        log.Errorf("template syntax error in %s: %v", name, err)
        return fiber.ErrInternalServerError
    }
    return err
}

When it happens

Trigger: Calling c.Render("./views/broken.tmpl", data) with no app.Config.Views, where broken.tmpl contains invalid Go template syntax such as '{{ .Name ' (unclosed action) or malformed delimiters.

Common situations: Using Render as a raw file loader for hand-written Go templates with syntax errors; mixing engine syntax (e.g. pongo/jet) with text/template rules; templates edited in production.

Related errors

• logtemplate: unknown tag
• failed to render: %w
• failed to execute: %w
• min constraint requires an argument
• max constraint requires an argument

AI-assisted analysis of gofiber/fiber@9a4c7e57fe (2026-08-04). Data as JSON: /data/errors/294e05deff07ff19.json. Report an issue: GitHub.