Playground

Runs the D17 wasm engine in the tab — no eelden serve. Durable OPFS when available; otherwise session memory. Pick a template, get a working app, edit it in place. Everything you build compiles to real .eel.

Hosted: play.eelden.dev

Local

cd clients/studio && npm install && npm run build:wasm && npm run dev:playground
# open http://127.0.0.1:5173/?local=1

build:wasm is required for the real engine. Without public/eelden_wasm.wasm, the UI falls back to an in-memory mock (also forced with ?mock=1).

Mobile e2e (360×640):

PLAYGROUND_URL='http://127.0.0.1:5173/?local=1' npm run test:playground
# Or one-shot (builds wasm + preview):
npm run test:playground:ci

What it is

A phone-first app builder on six part primitives — list, count, action, form, text, detail. No domain-named widgets. Row configuration is what makes an orders list look different from a skills list.

Surfaces:

• Start — three templates (order board, tiny adventure, start empty)
• App — the live app; Edit overlays handles and insert slots
• Sheets — add part, part settings, data, workspaces, under the hood (.eel)

Workspaces map to Eelden tenants in the product model. The wasm playground ABI is still single-tenant today (create / fork tenant stay serve-only); the adapter keeps a workspace ledger and reseeds through the real engine when you switch or copy. Snapshots and asof use the real wasm ops.

Engine

UI talks only through EngineAdapter (src/playground/engine/):

Adapter	Role
wasm.ts	Default — localEngine / eelden_wasm.wasm
mock.ts	Tests + missing-artifact / ?mock=1 fallback

Design

• internals/plans/playground-rebuild.md
• internals/review-guides/playground-rebuild.md

Deploy

Maintainers: see Deploy docs + playground.

Related

• Studio — serve-backed console (same package)
• Status — capability contract