# NaijaShield Backend
**Real-time fraud detection and intelligence infrastructure for Nigerian telecommunications.**
NaijaShield intercepts phone calls and SMS messages at the network level, classifies them with AI, and delivers instant warnings — without requiring an app on the user's device. The backend comprises two cooperating services: a .NET Core API that orchestrates the full threat pipeline and enterprise intelligence layer, and a Python FastAPI sidecar that handles voice transcription and deepfake analysis.
---
## Overview
| Service | Runtime | Role |
|---|---|---|
| **Core API** | ASP.NET Core (.NET 9, C#) | Threat pipeline, persistence, fraud ring intelligence, authentication, SignalR push |
| **AI Voice Sidecar** | Python 3.10+ (FastAPI) | Speech-to-text (Azure Speech), deepfake probability scoring |
**Live deployment:** `
api-naijashield-dev-a5ggd0e…`
---
## Key Features
**Threat Detection**
- Real-time classification of SMS and voice calls using Azure OpenAI (GPT-5.4 mini) via Microsoft Semantic Kernel
- Supports five Nigerian languages: English, Pidgin, Yoruba, Hausa, and Igbo — including code-switching
- Covers the major attack typologies: OTP phishing, bank impersonation, USSD tricks, vishing, and family social engineering
- Risk scoring (0–100) with deterministic status thresholds: Blocked ≥ 85, Monitoring ≥ 50, Allowed .azurecomm.net",
"AT-Username": "sandbox",
"AT-API-Key": "...",
"AzureOpenAI": {
"Endpoint": "https:// .openai.azure.com/",
"DeploymentName": "gpt-4o"
},
"Jwt": {
"Secret": "at-least-32-character-local-dev-secret",
"Issuer": "NaijaShield",
"Audience": "NaijaShieldClient",
"AccessTokenExpiryMinutes": 60,
"RefreshTokenExpiryDays": 7
},
"Jambonz": {
"AccountId": "...",
"ApiBaseUrl": "
your-jambonz-instance",
"ApiToken": "...",
"ServerUrl": "
your-backend-url"
}
}
```
### 3. Start the Core API
```bash
dotnet restore
dotnet run
```
The API starts on `
localhost …