DDT Software & E-Commerce Pvt. Ltd. is building a next-generation active reading and document annotation app for Android tablets and phones

. Users will be able to open PDFs and documents, highlight, annotate with a stylus, pull excerpts into a free-form workspace, link ideas together, and organise research visually. We need an Android developer with robust skills in custom rendering, touch/stylus input and performance optimisation to help build it from the ground up.

Key Responsibilities

- Build the core

PDF/document viewer with smooth scrolling, zooming and page rendering

- Develop annotation tools such as highlights, freehand ink, shapes, text notes, comments and bookmarks

- Implement stylus and multi-touch input

, including pressure sensitivity, palm rejection, pinch-to-zoom and gesture handling

- Build a free-form canvas workspace where users drag excerpts out of documents, group them, connect them, and link back to the source page

- Support multi-document views with side-by-side and split-screen layouts

- Add full-text search across documents and annotations, with OCR for scanned PDFs

- Export annotated documents as PDF with annotations flattened or kept editable

- Design local storage and sync logic for documents, annotations and workspaces, with offline-first behaviour

- Optimise for large documents

(500+ pages) through bitmap tiling, caching, memory management and background rendering

- Build tablet-first, adaptive UI that also works on phones and foldables

- Manage Play Store releases, crash monitoring and performance profiling

Required Skills & Experience





- 3–4 years of native Android development in

Kotlin and Java

- Strong experience with custom Views / Canvas drawing or

Jetpack Compose Canvas

- Hands-on work with

PDF rendering libraries

: Android PdfRenderer, PDFium, MuPDF, or commercial SDKs such as PSPDFKit/Nutrient or Apryse

- Solid understanding of

MotionEvent, gesture detection and multi-touch handling

- Experience with bitmap management, memory optimisation and avoiding OOM issues in graphics-heavy apps

- Strong

Kotlin Coroutines/Flow and background processing skills

- MVVM / Clean Architecture with Jetpack (ViewModel, Room, Navigation, WorkManager)

- Experience with the

Storage Access Framework and scoped storage for opening and saving user files

- Profiling skills with Android Studio Profiler, systrace/Perfetto and LeakCanary

- At least one shipped app involving a PDF viewer, note-taking, drawing/whiteboard, e-reader, or similar graphics-heavy work (Play Store link required)

Good to Have (Added Advantage)

- Stylus/ink SDK experience, such as Android Ink API, Samsung S Pen SDK or low-latency ink rendering

- OCR and text extraction

: Google ML Kit or Tesseract

- Knowledge of the

PDF specification and annotation standards (XFDF, PDF annotation objects)

- Undo/redo stack and command-pattern implementation

- Cloud sync and conflict resolution with Firebase or a custom REST backend

- React Native experience for cross-platform modules

- Node.js for building or integrating backend APIs

- OpenGL ES / Vulkan or hardware-accelerated rendering

- Importing DOCX, PPT, EPUB or web articles into a reading view

📌 Android Developer – Document Reading & Annotation App (Java/Kotlin) (Delhi)
🏢 DDT SOFTWARE u0026 E-COMM (OPC
📍 Delhi