---
title: "Explore a simulation's steps in details."
method: POST
path: "/trace"
tags: ["Calculations"]
---

# Explore a simulation's steps in details.

`POST /trace`

## Request body

- SituationInput — unresolved $ref

## Response `200`

The calculation details are sent back in the response body

- Trace
  - `requestedCalculations` string[]
  - `entitiesDescription` object
  - `trace` object

## Other responses

- `400` — The request is invalid. Details about the error are sent back in the response body
- `404` — A variable mentioned in the input situation does not exist in the loaded tax and benefit system. Details are sent back in the response body

## Changes

> 28 revisions in range; 1 could not be searched.

- **2022-10-16** `99fd939badee` — 1 breaking, 3 warning
  - the `trace/additionalProperties/value/items/` response's property type/format changed from `any`/`` to ``/`` for status `200`
  - the optional response header `schema` removed for the status `200`
  - the optional response header `schema` removed for the status `400`
  - the optional response header `schema` removed for the status `404`
- **2022-10-16** `89012c518ce9` — 1 breaking, 1 info
  - added required request body
  - added the media type `application/json` for the response with the status `200`
- **2018-08-01** `a3fca283cd57` — 2 breaking, 6 warning
  - removed the request body
  - removed the media type `application/json` for the response with the status `200`
  - the optional response header `Country-Package` removed for the status `200`
  - the optional response header `Country-Package` removed for the status `400`
  - …4 more

[Change history](https://skmtc.dev/openfisca/apis/country-package-name-web-api/changes/trace/post.md)

---

[API](https://skmtc.dev/openfisca/apis/country-package-name-web-api.md) · [All operations](https://skmtc.dev/openfisca/apis/country-package-name-web-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/openfisca/country-package-name-web-api/revisions/297f18b6e68f/schema)