UPLC Viewer

Browser-only utility for inspecting Untyped Plutus Core (UPLC) programs. Paste either UPLC source code or the CBOR-wrapped hex encoding of a script and the viewer will:

• Parse and pretty-print the UPLC term.
• Recover the script version.
• Produce the flattened binary encoding (hex) and the CBOR-wrapped variant.
• Run entirely in the browser using @harmoniclabs/uplc and companion libraries—no backend required.

Prerequisites

• Node.js 18 or later
• npm 9 or later

Getting started

cd webapp
npm install
npm run dev

Open the printed URL (defaults to http://localhost:5173) and paste either:

• Raw UPLC source ((program 1.1.0 ...) or a bare term such as (lam ...)).
• CBOR hex for a compiled script (for example the cborHex field emitted by cardano-cli).

The viewer automatically detects the format, formats the script body, and gives you copy-ready flat and CBOR hex strings.

Production build

npm run build   # type-checks and produces a static build in dist/
npm run preview # serve the production build locally

Project layout

• src/App.tsx – UI logic for parsing, formatting, and displaying UPLC.
• src/lib/uplcUtils.ts – Helpers for detecting input format, encoding scripts, and wrapping bytes as CBOR.
• src/App.css – Component styling.

Notes

• Scripts are parsed with the default Plutus v1.1.0 version when no (program …) header is present.
• Copy buttons rely on the Clipboard API and may require a secure context (HTTPS) in some browsers.