https://github.com/lambdasistemi/plutus-browser
Browser UI for the wasm32 Plutus evaluator (UPLC playground + snippets). PureScript + MUI; depends on lambdasistemi/plutus releases.
https://github.com/lambdasistemi/plutus-browser
browser plutus purescript uplc webassembly
Last synced: about 20 hours ago
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Browser UI for the wasm32 Plutus evaluator (UPLC playground + snippets). PureScript + MUI; depends on lambdasistemi/plutus releases.
- Host: GitHub
- URL: https://github.com/lambdasistemi/plutus-browser
- Owner: lambdasistemi
- Created: 2026-06-11T10:53:36.000Z (10 days ago)
- Default Branch: main
- Last Pushed: 2026-06-11T13:16:31.000Z (10 days ago)
- Last Synced: 2026-06-11T13:24:45.522Z (10 days ago)
- Topics: browser, plutus, purescript, uplc, webassembly
- Language: PureScript
- Homepage: https://lambdasistemi.github.io/plutus-browser/
- Size: 55.7 KB
- Stars: 0
- Watchers: 0
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# Plutus Browser
Browser UI for the wasm32 Plutus evaluator: UPLC playground with editor,
evaluator output, and browser-local versioned snippets.
Live app:
## What is this
Plutus Browser is a single-page application that evaluates Untyped Plutus
Core (UPLC) programs entirely in the browser. It embeds `uplc.wasm` — the
real Plutus CEK machine and cost model compiled to wasm32-wasi from the
32-bit-correct fork [lambdasistemi/plutus](https://github.com/lambdasistemi/plutus)
(release [1.65.0.0-wasm32.1](https://github.com/lambdasistemi/plutus/releases/tag/1.65.0.0-wasm32.1)) —
so evaluation results match the 64-bit chain byte for byte. No server is
involved: the wasm binary is bundled into the page and runs through a WASI
shim.
The UI is written in PureScript (react-basic + MUI, CodeMirror editor). It
ships 22 bundled example programs and lets you keep your own snippets, which
are versioned in a browser-local git repository (isomorphic-git over
lightning-fs, persisted in IndexedDB) — every edit is auto-committed, and
each snippet's history can be viewed and restored.
## Architecture
```mermaid
flowchart LR
subgraph BROWSER["Browser page (all client-side)"]
APP["Uplc.App
React + MUI UI"]
EDITOR["CodeMirror editor
SpaKit.CodeMirror"]
FMT["Uplc.Format
UPLC pretty-printer"]
RUNNER["Uplc.Runner"]
WASI["SpaKit.WasiRunner
browser_wasi_shim"]
WASM["uplc.wasm
Plutus CEK + cost model"]
GIT["SpaKit.BrowserGit + Uplc.SnippetStore
isomorphic-git"]
IDB[("lightning-fs
IndexedDB: uplc-snippets-v1")]
end
REL["lambdasistemi/plutus
release 1.65.0.0-wasm32.1"]
APP --> EDITOR
APP --> FMT
APP -->|"evaluate"| RUNNER
RUNNER --> WASI
WASI -->|"uplc evaluate [-c]"| WASM
APP -->|"save / load / history"| GIT
GIT --> IDB
REL -.->|"fetched at build time"| WASM
```
- `src/Main.purs` mounts the React app; `src/Uplc/App.purs` is the whole UI
(drawer with snippets, examples and history; editor; controls; output).
- `src/Uplc/Runner.purs` compiles the bundled wasm module and runs it as a
CLI: `uplc evaluate`, plus `-c` when the budget toggle is on.
- `src/Uplc/Examples.purs` is **generated** from `examples/*.uplc` by
`scripts/generate-examples.mjs` — edit the `.uplc` files, not the module.
- `src/bootstrap.js` is the esbuild entry that inlines `src/assets/uplc.wasm`
as bytes and exposes them to the PureScript side.
- Snippets live in a git repository at `/repo` inside a lightning-fs
filesystem named `uplc-snippets-v1`; saves, renames and deletes are git
commits (`src/Uplc/SnippetStore.*`).
## Install
There is nothing to install for normal use — open the
[live app](https://lambdasistemi.github.io/plutus-browser/).
To build the static site yourself (output is plain HTML + JS, host anywhere):
```sh
nix build
# result/ contains index.html and index.js
```
## Quickstart
```sh
nix develop
just install # npm ci
just bundle # downloads uplc.wasm, builds dist/
just serve # http://127.0.0.1:4173/
```
Open the URL, pick an example (e.g. `01-add-integers`) and press
**Evaluate** — the output panel shows `(con integer 42)`.
## Usage
Everything happens in the single page:
- **Editor** — CodeMirror with a UPLC pretty-printer. **Format** re-indents
the program (2/4/8 spaces, selectable); *auto format* formats on blur.
- **Evaluate** — runs the program through the wasm CEK. *auto evaluate*
re-runs after each edit (default debounce 350 ms, configurable). The
*show budget (-c)* toggle adds CPU and memory budget figures to the output.
- **Snippets** — *Quick add snippet* creates an empty named snippet;
*new from...* creates one from a copy of an existing snippet, a local
file, or a URL. Rename and delete from each row's hover actions.
- **Auto-versioning** — edits to a snippet are auto-committed (default
debounce 1500 ms). The **History** panel lists commits; selecting one
shows that version read-only, and **Restore version** commits it back.
- **Examples** — bundled programs, editable in place (the row shows
*edited example*), but edits are not persisted until you press **Save as
my snippet**. Examples cover integer/bytestring
builtins, if-then-else, lambdas, recursion via fixpoint, lists,
constr/case, and tracing/error.
Snippets are stored only in your browser (IndexedDB); clearing site data
deletes them.
## Documentation
- For AI agents, start at [AGENTS.md](AGENTS.md).
- Evaluator provenance and releases: [lambdasistemi/plutus](https://github.com/lambdasistemi/plutus).
## Development
```sh
nix develop # purs, spago, esbuild, node 22, just, purs-tidy, chromium
just build # regenerate examples module + spago build
just dev # spago build --watch
just fmt # purs-tidy format-in-place
just ci # install + lint + build + bundle + test
```
Tests are a Playwright suite (`test/uplc.spec.mjs`) that serves `dist/` and
exercises the real wasm evaluator in headless Chromium: example loading and
formatting, evaluation with and without budget, snippet creation from all
sources, rename/delete, and persistence across reloads. Run with `just test`
(needs a prior `just bundle`; the dev shell sets
`PLAYWRIGHT_CHROMIUM_EXECUTABLE`).
Verification as run by CI (`.github/workflows/ci.yml`):
```sh
nix build
nix develop --quiet -c just ci
```
Pushes to `main` deploy the nix-built site to GitHub Pages in workflow mode
(`.github/workflows/pages.yml`); pull requests get a static preview
(`.github/workflows/preview.yml`).