Contact person: Build Cross-Platform PDF Editing & Viewing SDK (Android · iOS · Web)

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Location: Lahore, Pakistan

Budget: Recommended by industry experts

Time to start: As soon as possible

Project description:
"We need an experienced C/C++ PDF-engine team or company to create a lightweight, cross-platform PDF SDK that will power multiple apps in our portfolio. The SDK must support advanced editing, annotation and Google-Docs-style comment threads while keeping the PDF text layer fully searchable. Target platforms:
Android (Kotlin wrapper)
iOS (Swift wrapper)
Web (WASM + TypeScript wrapper)

Key Features
In-place text editing — font, size , colour , bold/italic, underline/strikethrough, alignment, indentation; text remains searchable.
Annotation toolkit — highlight, ink/free-draw, shapes, sticky notes, stamps, image & text insert, signatures (flatten option).
Text-anchored comments — select text ➜ add comment, reply, resolve (threaded).
Viewer essentials — tiled GPU/Metal/WebGL rendering, 60 fps pinch-zoom & inertial scroll, dark-mode / colour inversion, open 500-page PDFs in ≤ 2 s on mid-range devices.
Live text search — instant matches, highlight, next/prev navigation.
Optional — liquid/reflow view, thumbnail & bookmark panel.
Binary-size targets — ≤ 10 MB Android .aar, ≤ 12 MB iOS .xcframework, ≤ 3 MB gzipped WASM bundle (to keep host apps ≤ 30 MB).

Technology Expectations
Shared C/C++ core using PDFium or MuPDF.
Android: JNI + Kotlin (Jetpack Compose demo).
iOS: Objective-C++ bridge + Swift / SwiftUI demo.
Web: WebAssembly via Emscripten + React/TypeScript demo.
Skia/OpenGL ES (Android), Metal (iOS), WebGL/Canvas (Web) for rendering.
Incremental save & full rewrite; output passes Adobe/Chrome/Safari viewers.
Crash-safe, with NDK logs ready for Crashlytics.

Deliverables
Source code of the C/C++ core and all platform wrappers.
Distributable SDK artefacts (.aar, .xcframework, npm package).
Sample apps for Android, iOS, Web demonstrating every feature.
API documentation & build instructions.
Performance and stability report (render speed, memory, crash-free run).
90-day critical-bug-fix warranty (negotiable).

8-Week Milestone Plan
WeekGoal
1. Core engine integrated; basic rendering on all platforms
2. Reader essentials (zoom/scroll, dark-mode, large-file test)
3. Annotation toolkit (highlight, ink, shapes, signatures)
4. In-place text editing prototype complete
5. Insertions & save/flatten pipeline
6. Live text search (API + UI)
7. Comment threads + liquid/reflow prototype, size trimming
8. Final QA, docs, sample apps, hand-over

Budget & Contract Type
Milestone based project. Please propose a total for the full 8-week scope (include milestone breakdown).

Required Experience
PDFium or MuPDF at source level
Android NDK, Kotlin/Compose
Objective-C++ / Swift / SwiftUI
WebAssembly / Emscripten / React
GPU/Metal/WebGL optimisation
Proven delivery of production PDF or graphics SDKs

To Apply, Please Provide
A concise technical approach (engine choice, comment-thread design, size-optimisation).
2–3 similar PDF/graphics projects (links, repos, or builds).
Confirmation you can meet the 8-week timeline.
Milestone-based fixed quote & post-delivery support terms." (client-provided description)