Browser Core
Tech Preview45/45 tests
Realtime document runtime

Not another PDF editor.A browser-native runtime engine.

Local-first. Realtime. Deterministic. The document engine that renders, edits and replays entirely in the browser.

Conceptual runtime visualization
Edit operationMove text spanPage 412.42:18.102applied

Contract Agreement

Text Layer
Annotations
Vector Objects
Raster Layer
Tiles
Base Raster
Command stream (live)Live
12.42.18.095setTextStyleid:3921
12.42.18.096moveTextSpanid:3921
12.42.18.097invalidateRegionpage:4
12.42.18.098buildRenderGraphnodes:1842
12.42.18.099generateTilesdirty:8
12.42.18.100drawTextRunruns:584
12.42.18.101compositeFrametime:16.7ms
PDF Bytes12.4 MB
IndexedDBCached
PDFium WASMActive
Render GraphNodes: 1,842
Command BufferCommands: 3,761
Textless TileTiles: 342
Final Composite16.7 ms
Render pipeline (live)
No backend roundtrip

Local-first by design

Textless tile rendering

No white-mask hacks

Deterministic replay

Every operation tracked

GPU ready

WebGL → WebGPU roadmap

Production verified

45/45 tests passing

The runtime pipeline

The website should sell the engine idea: local-first preview, deterministic render commands and backend-verified export.

📄
PDF Bytes
uploaded or restored
IndexedDB
session cache
PDFium WASM
raster + text objects
Render Graph
dirty invalidation
Command Buffer
deterministic draw ops
Textless Tile
source suppression
Final Preview
local composite

No backend roundtrip for every edit

The local runtime previews text style and move operations before authoritative save/export.

No white-mask replacement story

The core is moving toward real textless tile composition with PDFium WASM and provider fallbacks.

State is replayable

Operation replay, compaction and committed state make the preview feel recoverable instead of temporary.

Deep tech. Built different.

Use the page to attract technical users, partners and early-access conversations.

Render graph

Layer and node based rendering with deterministic dirty invalidation.

Textless tiles

PDFium-powered source suppression instead of pure drawRect masking.

Operation replay

Local edits can survive refresh and compact into committed state.

Interaction runtime

Layer focus, spatial index, ownership and worker resolve path.

GPU

GPU-first target

Canvas now, WebGL compositor next, WebGPU-ready structure.

SDK potential

A possible runtime layer for document SaaS, legal tools and e-signature products.

Local-first by design

Preview locally. Commit authoritatively.

Edits visible before backend save
IndexedDB document/session cache
Deterministic operation log
Refresh recovery and replay
Hybrid local + backend export
Honest early-access positioning

Operation replay

Replayed ops 128

Committed ops 94

Pending ops 34

Proof panel

Do not hide the engineering status. Make it the credibility layer.

45/45browser-core tests passing
3/3production move E2E verified
3/3production edit E2E verified
PDFiumWASM page raster and textless provider
Replaydocument operation replay and compaction
EarlyWebGL/WebGPU compositor still roadmap

Debug as product

The debug layer is not just internal. It explains why the engine is real.

Browser coreready
Tile providerpdfium-wasm
Final compositedrawBaseRasterTile → drawTextRun
visual-sourceexpanded source extent
cleanupsingle-object-expanded
Interaction ownerText Layer / Span
Layer viewer

Text Layer

Source suppression

Replacement text

Final composite


Trace

provider: pdfium-wasm

cache: hit

owner: span_1_14

Honest roadmap

Make the unfinished parts visible. That is stronger than pretending this is a finished generic SaaS.

01
Operation Inspector

Show operation log, compacted ops, committed ops and replay source in a dedicated view.

02
Tile latency tuning

Measure warm-cache PDFium textless rendering and optimize matching / encode path.

03
WebGL compositor

Move final composite toward GPU layer pipeline and texture cache.

04
Font atlas / SDF

Better text rendering path for speed, clarity and consistent previews.

05
Export equivalence

Compare optimistic preview against final authoritative PDF export.

Built for teams building the future of documents

SaaS platforms

Embed low-latency PDF interaction into web products.

Legal tech

Contract editing, review and annotation workflows.

eSignature

Faster flows with realtime visual feedback.

Automation

Document transformations with deterministic operations.

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Developers

Potential SDK/runtime layer for custom tools.

Show the engine before it is “finished”.

Position it honestly as an early technology preview and collect serious interest from people who understand document runtimes.