How I Fixed "A Possible Object Cycle Was Detected" in ASP.NET Core (And What I Learned About DTOs)

Muhammd Rehman Tahir — Thu, 16 Apr 2026 04:44:13 +0000

Yesterday I ran into a classic but dangerous issue while working on an ASP.NET Core API:

👉 "A possible object cycle was detected"

At first, everything was working fine… until I introduced some additional logic on top of my existing response. Suddenly, my API started failing during JSON serialization.

After digging deeper, I realized the root cause:

❌ I was directly returning EF Core entities
❌ Navigation properties created a circular reference
❌ The serializer went into an infinite loop

The structure looked something like this:
Entity → Navigation → Entity → Navigation → 🔁

💥 Boom — Object Cycle Error!

🔍 How I resolved it:

Instead of sending the full entity graph to the frontend, I:

✔ Trimmed the entity to only required properties
✔ Broke the circular reference manually
✔ Understood the importance of separating API models from DB models

🚀 Key Learning:

This issue made one thing very clear:

DTOs are not optional — they are essential.

Using DTOs helps you:
✔ Avoid circular reference issues
✔ Keep your API responses clean and controlled
✔ Improve performance
✔ Maintain proper architecture

⚠️ Developer Tip:

If you're exposing EF entities directly in APIs, you're just one change away from breaking your system.

Think long-term. Avoid quick fixes.

💬 Have you ever faced this issue in your APIs?

I just published my second NuGet package: Rehman.CurrencyTextify.Core

Muhammd Rehman Tahir — Wed, 11 Mar 2026 17:06:22 +0000

This lightweight and flexible package converts money amounts into text for 8 currencies: Dollar, Euro, Pound, Yen, Rupee, Rial, Dirham, and Dinar — now including PKR!

✨ Key Features:

Batch processing
Fuzzy spelling correction
Custom rounding modes
Capitalization styles
Subunit name overrides
Handling negative amounts

Whether you’re building financial apps, invoices, or reports, this package makes working with currencies in code fast, simple, and reliable.

💡 I’d love for you to try it out and share your feedback!

🔗 Check it out on NuGet : https://www.nuget.org/packages/Rehman.CurrencyTextify.Core/

Forem: Muhammd Rehman Tahir

How I Fixed "A Possible Object Cycle Was Detected" in ASP.NET Core (And What I Learned About DTOs)

🔍 How I resolved it:

🚀 Key Learning:

⚠️ Developer Tip:

I just published my second NuGet package: Rehman.CurrencyTextify.Core