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Overview Technology Preview

Core concepts

Architecture Runtime Render Graph PDFium WASM Textless Tiles Operation Replay Local-First Dirty Rendering Debug & Visibility

Developers

SDK (Planned)Integration Guide

Company

ArchitectureBrowser-native document runtime architectureA public architecture view of Browser Core: browser-side preview, PDFium-backed rendering, deterministic operations and backend-authoritative export.RuntimeA browser-side runtime for safe realtime document interactionHow Browser Core coordinates browser-local preview, runtime readiness, replayable operations, safe compositing and backend-authoritative export.Render graphRender graph planning for safe browser PDF previewHow Browser Core turns local document edits into structured visual responsibilities, command buffers, tile resolution and safe final preview output.PDFium WASMPDFium WASM for accurate browser-side PDF previewHow Browser Core uses PDFium WebAssembly for local page rastering, text awareness, textless tiles and safer live PDF previews.Textless tilesTextless tiles for cleaner PDF text editing previewsHow Browser Core removes old PDF text from live preview with small PDF-aware clean tiles instead of fake white overlay masks.Local-firstLocal-first PDF preview with backend authorityHow Browser Core gives PDF editing immediate browser-side preview while keeping save, export and persisted document state backend-authoritative.Operation replayOperation replay for refresh-safe document previewsHow Browser Core keeps local edits visible across refreshes while preserving backend-authoritative save and export.Dirty renderingDirty rendering for focused, safe PDF preview updatesHow Browser Core tracks what changed in the live preview using dirty nodes, dirty regions, command buffers and safe final compositing.Debug visibilityDebug visibility for browser-side PDF runtimesHow Browser Core makes local PDF preview behavior observable across operations, render graph state, dirty rendering, tiles, interaction and performance.Technology previewTechnology preview status for Browser CoreCurrent Browser Core technology preview status: browser runtime active, PDFium-backed preview path, backend-authoritative export and roadmap limits.RoadmapBrowser Core engineering roadmapThe Browser Core roadmap for stable local PDF editing, safer visual cleanup, broader document coverage and production-grade save/export workflows.SDK directionFuture SDK direction for embedded document runtimesFuture SDK direction for embedding Browser Core style document runtime capabilities into document products.ArticleWhy PDF editors feel slowBackend render loops make every edit wait for network and regeneration. A browser runtime can make preview feel immediate.ArticlePDFium WASM browser renderingWhere PDFium WebAssembly fits in a browser-side preview path for page raster work, text readiness and clean composition.ArticleTextless tile renderingWhy source-suppressed tiles are cleaner than white overlay masks for PDF text replacement previews.ArticleLocal-first document runtimeHow browser-owned preview sessions and backend-authoritative export can work together without pretending the browser is the final source of truth.ArticleRender graph document editingA public render graph story for document preview, affected regions and predictable compositing.ArticleDirty region rendering in the browserWhy affected-region rendering matters when small edits should not redraw the entire document preview.ArticleOperation replay for document editingRecovering local preview state with deterministic operations while clearing committed work after backend save.ArticleBrowser runtime vs backend render loopA practical comparison of local interactive preview and backend-authoritative PDF save/export.ArticleDebug visibility for document enginesWhy document runtimes need visible health, replay status, provider state and frame timing without exposing private internals.ArticleGPU document rendering roadmapHow GPU compositing can evolve browser-native document runtimes after the safe Canvas/PDFium-backed path is established.

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Local-first

Local-first PDF preview with backend authority

Local-first means the browser can show safe, immediate edit previews while the backend remains responsible for authoritative save and export.

Technology previewPDFium WASM activeReplay enabled

Runtime pipeline

From PDF bytes to final composite, all inside the browser preview path.

01User edit

02Local operation

03Render graph

04Textless cleanup

05Preview update

06Backend save

Problem

What this changes

Traditional PDF preview loops send every small edit to the backend, wait for document mutation, render a new preview and then update the browser. That is reliable, but it makes style changes, text moves and interaction feel slower than they need to.

Browser Core approach

Runtime-first preview

Browser Core uses a hybrid authority model: the browser owns live preview, local operations, interaction state, render graph composition and replay before commit; the backend owns imported document state, persistence, final save, export and authoritative revisions.

What this solves

Updates the live preview immediately without waiting for a backend preview image

Rebuilds uncommitted preview state after refresh through operation replay

Removes committed operations after save so backend-updated content is not drawn twice

Prefers a safe previous frame over an unsafe fast frame when cleanup is not ready

Current status

Hybrid browser/backend authority

Immediate local preview

Refresh-safe operation replay

Safe text cleanup before replacement

Backend-authoritative save and export

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