> For the complete documentation index, see [llms.txt](https://www.bluegamma.io/documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.bluegamma.io/documentation/integrations/api/how-to-guides/fetching-an-inflation-curve.md).

# Fetching Inflation Curves

Fetch zero-coupon inflation curves for UK RPI, UK CPI and EU HICP for inflation-linked bond analysis, real rate calculations, and inflation hedging.

The `/inflation_curve` endpoint returns zero-coupon inflation rates for tenors from 1Y to 50Y, derived from inflation swap market data. Use this when you need to **price inflation-linked instruments**, calculate **real rates**, or analyse **breakeven inflation**.

***

## When to Use Inflation Curves

| Use Case                           | Why Inflation Curves?                                        |
| ---------------------------------- | ------------------------------------------------------------ |
| **Real rate calculation**          | Subtract inflation from nominal swap rates to get real rates |
| **Inflation-linked bond analysis** | Price or value index-linked gilts and linkers                |
| **Breakeven inflation**            | Compare implied inflation expectations across tenors         |
| **Inflation hedging**              | Size and value inflation swap positions                      |

***

## Basic Example

```python
import requests

url = "https://api.bluegamma.io/v1/inflation_curve"
headers = {"x-api-key": "your_api_key"}

params = {
    "index": "UK RPI"
}

response = requests.get(url, headers=headers, params=params)
data = response.json()

for point in data["rates"]:
    print(f"{point['tenor']}: {point['zc_rate']:.2f}%")
```

```bash
curl -X GET "https://api.bluegamma.io/v1/inflation_curve?index=UK%20RPI" \
  -H "x-api-key: your_api_key_here"
```

**Response:**

```json
{
  "index": "UK RPI",
  "discount_index": "SONIA",
  "rates": [
    {"tenor": "1Y", "zc_rate": 4.96},
    {"tenor": "2Y", "zc_rate": 4.32},
    {"tenor": "3Y", "zc_rate": 4.12},
    {"tenor": "5Y", "zc_rate": 3.76},
    {"tenor": "10Y", "zc_rate": 3.44},
    {"tenor": "20Y", "zc_rate": 3.35},
    {"tenor": "30Y", "zc_rate": 3.31},
    {"tenor": "50Y", "zc_rate": 3.36}
  ],
  "timestamp": "2026-04-16"
}
```

| Field            | Description                                         |
| ---------------- | --------------------------------------------------- |
| `rates`          | Array of zero-coupon inflation rate points by tenor |
| `zc_rate`        | The zero-coupon inflation rate as a percentage      |
| `tenor`          | The maturity point on the curve (1Y to 50Y)         |
| `discount_index` | The nominal rate index used for discounting         |
| `timestamp`      | When the underlying market data was captured        |

{% hint style="info" %}
**Full curve:** The API returns rates for every year from 1Y to 50Y. The response above is abbreviated for clarity.
{% endhint %}

***

## Use Case: Calculating Real Rates

Subtract the implied inflation rate from nominal swap rates to get the real rate at each tenor:

```python
import requests

headers = {"x-api-key": "your_api_key"}

# Fetch the nominal SONIA swap curve
swap_response = requests.get(
    "https://api.bluegamma.io/v1/get_swap_curve",
    headers=headers,
    params={"index": "SONIA"}
)
swap_curve = {p["tenor"]: p["swap_rate"] for p in swap_response.json()["swap_rates"]}

# Fetch the UK RPI inflation curve
inflation_response = requests.get(
    "https://api.bluegamma.io/v1/inflation_curve",
    headers=headers,
    params={"index": "UK RPI"}
)
inflation_curve = {p["tenor"]: p["zc_rate"] for p in inflation_response.json()["rates"]}

# Calculate real rates for common tenors
for tenor in ["2Y", "5Y", "10Y", "20Y", "30Y"]:
    if tenor in swap_curve and tenor in inflation_curve:
        real_rate = swap_curve[tenor] - inflation_curve[tenor]
        print(f"{tenor}: Nominal {swap_curve[tenor]:.2f}% - Inflation {inflation_curve[tenor]:.2f}% = Real {real_rate:.2f}%")
```

***

## Use Case: Comparing UK and Eurozone Inflation

```python
import requests

headers = {"x-api-key": "your_api_key"}
url = "https://api.bluegamma.io/v1/inflation_curve"

uk_rpi = requests.get(url, headers=headers, params={"index": "UK RPI"}).json()
eu_hicp = requests.get(url, headers=headers, params={"index": "EU HICP"}).json()

uk_rates = {p["tenor"]: p["zc_rate"] for p in uk_rpi["rates"]}
eu_rates = {p["tenor"]: p["zc_rate"] for p in eu_hicp["rates"]}

for tenor in ["1Y", "2Y", "5Y", "10Y", "30Y"]:
    spread_bps = (uk_rates[tenor] - eu_rates[tenor]) * 100
    print(f"{tenor}: UK RPI {uk_rates[tenor]:.2f}% | EU HICP {eu_rates[tenor]:.2f}% | Spread {spread_bps:+.0f}bps")
```

**Output (April 2026):**

```
1Y: UK RPI 4.96% | EU HICP 3.20% | Spread +176bps
2Y: UK RPI 4.32% | EU HICP 2.68% | Spread +164bps
5Y: UK RPI 3.76% | EU HICP 2.28% | Spread +148bps
10Y: UK RPI 3.44% | EU HICP 2.22% | Spread +121bps
30Y: UK RPI 3.31% | EU HICP 2.35% | Spread +96bps
```

***

## Parameters

| Parameter        | Required | Description                                         |
| ---------------- | -------- | --------------------------------------------------- |
| `index`          | Yes      | Inflation index: `UK RPI`, `UK CPI`, or `EU HICP`   |
| `valuation_time` | No       | Historical timestamp (ISO 8601) for reproducibility |

***

## Supported Indices

| Index     | Region         | Discount Index | Description                                                                                                                          |
| --------- | -------------- | -------------- | ------------------------------------------------------------------------------------------------------------------------------------ |
| `UK RPI`  | United Kingdom | SONIA          | Retail Prices Index                                                                                                                  |
| `UK CPI`  | United Kingdom | SONIA          | Consumer Prices Index, derived from RPI minus a market-implied wedge ([methodology](/documentation/methodology/inflation-curves.md)) |
| `EU HICP` | Eurozone       | 6M EURIBOR     | Harmonised Index of Consumer Prices                                                                                                  |

***

## Reproducibility with `valuation_time`

Lock in the inflation curve at a specific point in time:

```python
params = {
    "index": "UK RPI",
    "valuation_time": "2026-03-31T16:00:00Z"
}

response = requests.get(url, headers=headers, params=params)
```

```bash
curl -X GET "https://api.bluegamma.io/v1/inflation_curve?index=UK%20RPI&valuation_time=2026-03-31T16%3A00%3A00Z" \
  -H "x-api-key: your_api_key_here"
```

***

## Related Endpoints

| If you need...             | Use                                                                                               |
| -------------------------- | ------------------------------------------------------------------------------------------------- |
| Nominal swap rates         | [`/get_swap_curve`](/documentation/integrations/api/how-to-guides/fetching-a-swap-curve.md)       |
| Government bond yields     | [`/gov_yield`](/documentation/integrations/api/how-to-guides/fetching-a-government-bond-curve.md) |
| Forward rates              | [`/forward_curve`](/documentation/integrations/api/how-to-guides/getting-a-forward-curve.md)      |
| Zero rates for discounting | [`/zero_rate`](/documentation/integrations/api/how-to-guides/fetching-zero-rates.md)              |

***

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