---
title: "Simulate a rent revision"
method: POST
path: "/leases/{lease_id}/rent-revisions/simulate"
tags: ["Rent Revisions"]
---

# Simulate a rent revision

`POST /leases/{lease_id}/rent-revisions/simulate`

## Request

- Base URL: `https://api.faireplace.com/api`
- URL: `https://api.faireplace.com/api/leases/{lease_id}/rent-revisions/simulate`
- Auth: HTTP bearer

Simulates an IRL-based rent revision for a lease **without persisting anything**.

Given a target IRL reference quarter and an effective date, the API computes the new
rent that would result from indexation, based on the lease's current rent and its
baseline IRL value. Use this to preview a revision before recording it.

## Usage Example

```bash
curl -X POST https://api.faireplace.com/api/leases/660e8400-e29b-41d4-a716-446655440001/rent-revisions/simulate \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "new_irl_quarter": "T3-2024",
    "effective_date": "2025-07-01"
  }'
```

**Response**:
```json
{
  "previous_rent": 1200.00,
  "new_rent": 1236.00,
  "old_irl_quarter": "T3-2023",
  "old_irl_value": 140.59,
  "new_irl_quarter": "T3-2024",
  "new_irl_value": 144.81,
  "variation_percentage": 3.00,
  "effective_date": "2025-07-01",
  "monthly_increase": 36.00
}
```

## Path parameters

- `lease_id` string, uuid, required

## Request body

- SimulateRevisionRequest: Request to simulate a rent revision (IRL indexation) without persisting anything. The simulation computes the new rent that would result from applying the provided IRL reference quarter, based on the lease's current rent and its baseline IRL value.
  - `new_irl_quarter` string, required: Target IRL reference quarter to apply, in the format `T{quarter}-{year}`. Must not be empty. The matching IRL index value must exist in the rent-indices catalog.
  - `effective_date` string, date, required: Effective date of the simulated revision (ISO 8601 `YYYY-MM-DD`).

## Response `200`

Revision simulated successfully

- RevisionSimulationResponse: Result of a rent revision simulation. Amounts are expressed in euros (decimal). The simulation does not modify the lease.
  - `previous_rent` number, double, required: Current rent before revision (in euros).
  - `new_rent` number, double, required: Computed rent after revision (in euros).
  - `old_irl_quarter` string, required: Baseline IRL reference quarter currently applied to the lease.
  - `old_irl_value` number, double, required: Official IRL value for the baseline quarter.
  - `new_irl_quarter` string, required: IRL reference quarter applied in the simulation.
  - `new_irl_value` number, double, required: Official IRL value for the new quarter.
  - `variation_percentage` number, double, required: Percentage variation between the old and new rent.
  - `effective_date` string, date, required: Effective date of the simulated revision (ISO 8601).
  - `monthly_increase` number, double, required: Monthly rent increase resulting from the revision (in euros).

## Other responses

- `400`: Bad request
- `401`: Unauthorized
- `403`: Forbidden
- `404`: Not found
- `422`: Unprocessable Entity
- `500`: Internal Server Error

---

[API](https://skmtc.dev/faireplace/apis/faireplace-property-management-api.md) · [All operations](https://skmtc.dev/faireplace/apis/faireplace-property-management-api/llms.txt) · [OpenAPI document](https://skmtc.dev/faireplace/apis/faireplace-property-management-api/revisions/69de39762919?raw)