Live HTML preview with full CSS and JavaScript support. Test responsive designs, view syntax highlighting, and render in sandboxed iframe.
- Live preview in a sandboxed iframe as you type
- Full CSS and JavaScript support for realistic testing
- Device-size presets (mobile, tablet, desktop) for responsive checks
- Syntax highlighting and error hints in the editor
- No uploads; everything runs in your browser
Quickly test HTML snippets, email templates, or small demos without spinning up a server or deploying. Sandboxing keeps your machine safe.
Spoold is a free developer toolbox that detects what you paste and opens the right tool.
- No sign-up – Use every tool without an account.
- Runs in your browser – Your data stays on your device; we don’t store or log your input.
- Paste and go – Paste JSON, HTML, JWT, curl, Base64, or any text on the homepage and Spoold suggests the right tool.
- One place for many tools – JSON formatter, JWT decoder, Base64, UUID generator, regex tester, curl-to-code, and more.