# GET Notional Cap

### /notional\_cap

```json
/notional_cap/{symbol_id}
```

**Example Query:**

```
https://base-hedger82.rasa.capital/notional_cap/1
```

**Example Response:**

```json
{
  "total_cap": "2344336.83177192369792522000000000",
  "used": "17746.15500000000000000000000000"
}
```

#### **Data Source**

Values are configured and managed exclusively by the hedger. These caps are set per trading pair and reflect the hedger’s risk management strategy for individual assets.

## **Notional Cap Implementation (Rasa)**

### Router

```python
@common_router.get(
    '/notional_cap/{symbol_id}',
    responses={status.HTTP_200_OK: {"model": OpenInterestResponseSchema}},
    response_model=OpenInterestResponseSchema,
    dependencies=[
        Depends(CustomRateLimiter(times=1, seconds=1)),
        Depends(CustomRateLimiter(times=40, minutes=1)),
        Depends(CustomRateLimiter(times=1500, hours=1)),
    ]
)
@with_context_db_session
async def get_notional_cap(symbol_id: int):
    symbol_id_validator(symbol_id)
    total_cap, used = await OpenCapEngine.get_cap_and_used_amount_async(symbol_id, from_stats=True)
    apm.label(total_cap=total_cap, used=used)
    return {"total_cap": total_cap, "used": used}

```

### Logic

* Ensures the provided `symbol_id` exists and is well-formed; raises a 400/422 if not.
* Queries the hedger’s capacity engine for the per-symbol maximum notional cap and current usage.
* Emits metrics for monitoring and alerting.
* FastAPI serializes this to JSON matching `OpenInterestResponseSchema`:

```python
class OpenInterestResponseSchema(BaseModel):
    total_cap: Decimal
    used: Decimal
```

#### Steps to Implement Your Own Version

**Define the Response Schema**

```python
class OpenInterestResponseSchema(BaseModel):
    total_cap: Decimal
    used: Decimal
```

**Implement Symbol Validation**

* Write `symbol_id_validator(symbol_id: int)` that checks against your `Symbol` table or whitelist.

**Build The Capacity Engine**

* In `OpenCapEngine`, implement `get_cap_and_used_amount_async(symbol_id, from_stats=True)` to return `(Decimal total_cap, Decimal used)`, using:
  * **Per-symbol config** table for maximum caps.
  * **Positions** table to sum currently open notional on that symbol.

**Add the FastAPI Route**

* In your `common_router`, add the `GET /notional_cap/{symbol_id}` handler as shown, importing the schema, validator, and engine.
* Attach the same rate-limiting and `@with_context_db_session` decorators.