The missing standard for server-driven displays.

A wire protocol, a typed schema and a multi-runtime client kit, Apache 2.0, multi-language, broadcast-grade and IoT-grade.

A serveur authoritatif détient un état temps-réel. Il doit le pousser à un display passif (browser, kiosque natif, OBS browser source, iframe, terminal, mobile) qui le rend visuellement. Le display n'a aucune logique métier, ne mute pas le state local, ne fait aucun calcul. Il rend, point.

This pattern is everywhere — broadcast overlays, trading dashboards, NOC walls, esports brackets, ATC consoles, industrial SCADA, live betting tickers, conference Q&A boards, digital signage, game spectator UIs — and is systematically reimplemented ad-hoc in every domain. Lumencast extracts the kernel as :

• LSDP/1 — Leaf State Delta Protocol — a WebSocket protocol that pushes typed state at leaf-grain (path → value), with snapshot+delta, sequenced delivery, gap detection, reconnect, and token rotation
• LSML 1.1 — Lumencast Scene Markup Language — a JSON content-addressed format describing a tree of 9 closed primitives (stack, grid, frame, text, image, shape, media, repeat, instance), with bindings, GPU-only animations, operator-input metadata, and 1.1+ extensions (universal props, multi-fill / gradients, vendor primitives via §17)
• Multi-language — TypeScript / Go / Rust / Python — cross-paradigm, conformance-suite-tested

The "real-time display" pattern is everywhere yet there is no shared protocol :

Lumencast fills the gap : an open protocol + schema you self-host, multi-language, broadcast-grade and dashboard-ready.

1. Push leaf-grain — state travels as path → value patches at the leaf level. The client maintains path → signal. Only components reading that path re-render. No DOM diff. No reconciliation.
2. Closed primitive catalog — the runtime renders only the 8 LSML primitives. No eval, no dangerouslySetInnerHTML, no arbitrary HTML. Security by construction.
3. Content-addressed scene bundle — the bundle's identity is its sha256 hash. Cache forever. Multiple versions co-exist transparently. Rollback is just an URL change.

More languages and runtimes (Vue, Svelte, Flutter, TUI, native) land in subsequent waves once wave 1 stabilises.

The first Layer 5 authoring tool ships in wave 3a :

• lumencast-figma — open-source Figma plugin that exports Figma frames to LSML 1.1 bundles (.lsml) and reimports them back. No JSON written by hand, full LSML 1.1 surface (text / shape / image / frame / stack / instance / multi-fill gradients / Figma variable tokens / operator inputs). Apache 2.0, networkAccess: none, zero telemetry. The plugin is the leftmost arrow of the Figma → Prism → Orion pipeline.

This project is early. Specs are draft, no SDK has shipped a v0 release yet. The conformance suite ships v0 with 16 scenarios covering the LSDP/1 + LSML 1.0 contract surface.

Watch the org for releases — when wave 1 SDKs land their initial v0.1.0, this README will reflect it.

• LSDP/1 — wire protocol
• LSML 1.0 — scene format
• Runtime API contract
• Performance budgets
• Error code taxonomy
• Conformance suite

• Contributing guide
• Governance model
• Code of conduct
• Security policy
• Decision log
• RFC process

Apache 2.0 across the entire ecosystem.

The project name "Lumencast" and the LSDP/LSML acronyms are trademarked separately ; only conformance-passing implementations may use the name without qualification (see GOVERNANCE.md § Brand).