Technical Assessment

Complete the assessment in 3 days or otherwise stipulated. Do read the following details carefully and thoroughly for the requirements. If you have any queries on the assessment you may ask your interviewer for the contact. If you need time extension do request from your interviewer.

Problem Statement

Create a React/Svelte frontend in Typescript and NodeJS web backend in Typescript/Javascript with the following functionalities.

1. Upload a CSV file with appropriate feedback to the user on the upload progress. Data needs to be stored in a database.

2. List the data uploaded with pagination.

3. Search data from the uploaded file. The web application should be responsive while listing of data and searching of data.

4. Proper handling and checks for the data uploaded.

5. Real-time collaboration. The application must support two browser sessions simultaneously editing/searching the same dataset. When one user uploads a new CSV that overlaps with existing records (matching by a unique identifier in the data), the application must:

   • Detect duplicate/conflicting records
   • Display a real-time diff UI (without page refresh) showing what changed between the old and new data
   • [Optional] User can be allowed to choose to which version of the data to keep. Tha updates should also be reflected in real-time(within 3 seconds).

Submission Requirement

In your submission, must include the following:

1. Use this csv file as the sample

2. Include unit tests with complete test cases including edge cases.

3. Provide a git repository for us to assess your submission.

4. Provide a docker compose file to run the necessary components for your application.

5. Provide a readme in the git repository on how to setup and run the project.

Other notes

• You will be expected to run and demo your application running the docker compose file during the interview.
• During the demo, two browser tabs/windows should be opened and you will be required to perform the conflicting uploads simultaneously. You must explain every design decision in their conflict resolution strategy.

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How to run this project

Docker Compose (recommended for the interview demo)

Requires Docker and Docker Compose v2.

docker compose up --build

Open http://localhost:8080. Postgres is exposed on localhost:5432 for debugging.

The web container serves the built React app via Nginx and proxies /api and /socket.io to the api service.

Stop and remove containers:

docker compose down

Local development (no Docker for Node)

1. Start PostgreSQL 16+ and create a database (or use the db service only: docker compose up db).

2. Backend:

   cd backend
   npm install
   export DATABASE_URL="postgresql://postgres:postgres@localhost:5432/csvcollab"
   export CORS_ORIGIN="http://localhost:5173"
   npm run dev

3. Frontend (new terminal):

   cd frontend
   npm install
   npm run dev

   Open http://localhost:5173. Vite proxies /api and WebSocket traffic to the backend on port 3001.

Sample CSV

Use the provided data.csv. The business unique key is the CSV column id (distinct from the Postgres surrogate key).

API overview

Method	Path	Description
GET	/api/health	Liveness
POST	/api/upload	multipart/form-data field file (CSV)
GET	/api/records?page=&limit=&q=	Paginated listing and ILIKE search
GET	/api/conflicts	Open conflict queue
POST	/api/conflicts/resolve	JSON { batchId, recordId, choice: "keep_old" | "keep_new" }

Realtime events (Socket.IO)

Clients join room collab on connect. Events:

• collab:conflicts — new overlapping rows detected after an upload (diff payload + batchId).
• collab:records_updated — inserts or post-resolve refresh signal.
• collab:resolved — a conflict was resolved.

The UI refetches /api/records and /api/conflicts on these events so a second browser tab updates without a full page reload.

Conflict strategy (for the demo narrative)

• Rows are validated with Zod (required fields, basic email shape, no empty body).
• Duplicate id values inside one upload are rejected.
• New id values are inserted immediately.
• Existing id values with identical field content are counted as skipped unchanged.
• Existing id values with any differing field become a pending conflict: stored in pending_conflicts, broadcast over Socket.IO, and shown as a per-field diff. Users may keep stored or keep incoming; keep_new bumps version on records so collaborators can see data changed.

Tests

cd backend && npm test

Covers diff detection and validation edge cases (invalid email, empty body, duplicate ids in file).