Cross-Platform Task Management App

Backend Developer (.NET + Azure + SQL) – Complex B2B App

Type: Freelance / Contract (potential long-term)
Location: Remote (must overlap with IST)
Stack: .NET 8, C#, Azure, Azure SQL, REST APIs, Git
cross platform (android/ios/windows/macos)
About the project (high-level)

I’m building a B2B operations / scheduling application with Flutter as the frontend (mobile + desktop).

The system has:

Multiple related “entities” (think projects, tasks, resources, timelines, etc.)

A lot of linked tables (like multiple spreadsheets talking to each other)

Complex rules: when data changes in one table, related data across other tables must update consistently.

I need a backend that can handle complex relationships and cascading updates reliably, and is designed to scale over time.

(Full product details will be shared after NDA.)

What you’ll work on

Data modelling (relational SQL)

Design a normalized relational schema for:

Projects / main records

Related sub-entities (e.g. items, resources, events, schedules, assignments, etc.)

Set up proper foreign keys, constraints and indexes.

Ensure the model supports:

Filtering by multiple dimensions

Linked “sheet-like” views (one change affects several views)

Backend API in .NET + Azure SQL

Build a .NET 8 Web API with:

Clean endpoints for CRUD and listing/filtering of entities

Business logic for cascading updates (if field X changes, update related records in a safe, transactional way)

Role/permission-aware access (different user types see/edit different things)

Use a clean structure (controllers → services → repositories, or similar).

Azure setup

Deploy the backend to Azure (App Service / Functions – we can decide together).

Configure Azure SQL Database and connect it securely.

Set up:

Environment-based config (dev/stage/prod)

Key Vault for secrets

Basic logging & monitoring (Application Insights or similar)

Integration with Flutter frontend

Define and stabilise API contracts (request/response DTOs) for the Flutter team.

Provide Swagger/OpenAPI and short dev-facing docs.

Security & code quality

Use Git (GitHub or similar) from day one.

Clean, maintainable code (no god classes, no copy–paste chaos).

Be willing to sign NDA and IP assignment; all code and architecture belong to the client.

Must-have skills

Strong C# / .NET (preferably .NET 6/7/8)

Solid experience with relational databases (Azure SQL or SQL Server / PostgreSQL)

Experience building REST APIs used by mobile/web frontends

Practical experience deploying to Azure (at least App Service + SQL + basic monitoring)

Comfortable designing schemas where many tables depend on each other and updates must stay consistent

Good communication in English and ability to work independently

Nice-to-haves

Experience with Azure Functions, Key Vault, and Application Insights

Experience with real-time updates (SignalR, WebSockets, etc.)

Experience in B2B / internal tools with lots of “sheet-like” data and complex filters

Exposure to Flutter projects (even just from the API side)

Engagement details

Initial scope:

Design the DB schema

Implement the core API for main entities and their dependencies

Set up Azure deployment (dev + simple prod)

If collaboration works well, there’s ongoing work:

More modules

More complex rules/permissions

Performance tuning & reporting