MASTIK Calculator Backend

FastAPI backend implementing an Israeli net-salary calculator and credit-points logic.

Requirements

• Python 3.10+
• Install dependencies:

pip install -r requirements.txt

Run locally

• Start the FastAPI app (recommended):

uvicorn app.main:app --reload --host 0.0.0.0 --port 8000

• Health: GET /health
• Root: GET /

API (key endpoints)

• POST /api/v1/calculator/calculate
  • Calculate net salary and credit points. Body follows the CalculatorInputs model (see app/models/calculator.py).
• GET /api/v1/calculator/tax-brackets
  • Returns configured tax brackets.
• GET /api/v1/calculator/constants
  • Returns constants such as national insurance and credit point values.

Example POST /api/v1/calculator/calculate payload (minimal):

{
  "employment_type": "employee",
  "gross_salary": 15000.0,
  "pension_rate": 6.0,
  "age": 31,
  "gender": "other"
}

Project layout

/
├── app/
│   ├── main.py                 # FastAPI application
│   ├── models/
│   │   └── calculator.py       # Pydantic models (CalculatorInputs, results)
│   ├── services/               # Calculation logic (taxes, credits)
│   │   ├── tax_calculator.py
│   │   ├── multi_source_calculator.py
│   │   └── self_employed_calculator.py
│   ├── routers/                # API routes
│   │   └── calculator.py
│   └── utils/
│       └── tax_constants.py    # Tax brackets, rates, constants
├── requirements.txt
├── lambda_handler.py           # AWS Lambda handler
├── Dockerfile                  # Docker for app
├── Dockerfile.lambda           # Docker for Lambda
├── docker-compose.lambda.yml   # Compose for Lambda testing
├── cloudformation.yml          # AWS CloudFormation template for deployment
├── iam-policy.json             # IAM policy for Lambda execution
├── lambda-ecr-policy.json      # ECR policy for Lambda
├── deploy.sh                   # Deployment script

Key files:

• app/services/tax_calculator.py — credit points, income-tax, NI, health tax and pension calculations.
• app/utils/tax_constants.py — values for tax brackets, rates, and credit-point monetary value.

Lambda & AWS Deployment

• CloudFormation: cloudformation.yml defines the complete infrastructure.
• Docker: Dockerfile.lambda builds a Lambda container image; use docker-compose.lambda.yml for local testing.
• Deploy: Use deploy.sh to push to AWS.

Tests

• Unit tests: pytest -q

python -m pytest -q

Development notes

• Use app.models.calculator.CalculatorInputs when crafting API requests; it documents all supported fields for credit calculation (children, spouse, education, immigration, foreign worker, etc.).
• Credit points logic is implemented in app/services/tax_calculator.py::calculate_credit_points.
• The default uvicorn invocation should use app.main:app from the repo root.