Building a Dynamic Profile API in ASP.NET Core for HNGi Stage 0 🐱💻

Anazodo Michael — Sun, 19 Oct 2025 18:42:13 +0000

I just completed Stage 0 of the HNGi13 backend internship, and it was a fantastic exercise in building a dynamic REST API from scratch using ASP.NET Core.

The task was simple on the surface: create a /me endpoint that returns my profile information and a dynamic cat fact fetched from an external API. But it taught me a lot about real-world API practices.

Here’s how I approached it:

Setting up the project

Used Visual Studio to create an ASP.NET Core Web API.
Added User Secrets locally and mirrored them as Azure Application Settings for deployment.

Fetching dynamic data

Integrated the Cat Facts API (https://catfact.ninja/fact) using HttpClient.
Added a 5-second timeout and proper error handling, returning 502 Bad Gateway if the external API failed.

Structuring the response

Returned JSON exactly matching the task spec:

 {
   "status": "success",
   "user": {
     "email": "...",
     "name": "...",
     "stack": "C#/.NET"
   },
   "timestamp": "2025-10-19T14:00:00.000Z",
   "fact": "Cats sleep 70% of their lives."
 }

Used UTC ISO 8601 timestamps, ensuring every request shows the current time.

Deployment

Deployed on Azure App Service using Visual Studio’s publish profile.
Added profile secrets in Application Settings for production.
Tested /me endpoint from multiple networks to confirm it worked reliably.

Key takeaways

Learned how to consume third-party APIs safely with timeouts and error handling.
Understood the importance of environment-specific configuration (User Secrets vs. production settings).
Reinforced JSON response consistency and API design best practices.

Outcome

A fully working /me endpoint that dynamically fetches cat facts.
Proper error handling and fallback messages in case the Cat Facts API is down.
Ready for submission to HNGi and demonstrates clean code, proper logging, and deployment skills.

Forem: Anazodo Michael

Building a Dynamic Profile API in ASP.NET Core for HNGi Stage 0 🐱💻

Here’s how I approached it:

Outcome